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For my final project I built a sous-vide immersion cooker

194 points by arbesfeld 12y ago

andr 12y ago
I've never understood the need for a complicated sous-vide setup. I've found that water at 80 degrees Celsius in a heavy pot with the lid on will remain sufficiently hot for 30-45 minutes. If not, you can always swap the water halfway through.
- NoNotTheDuo 12y ago
  I have one created using an Arduino and a Crockpot. The biggest thing for me is that I can throw some steaks in at 730am when I leave for work and when I get home at 530pm they are ready to eat (or sear-then-eat, I guess). I think it's the same argument as why you would want a crockpot in your kitchen, versus a normal pot.
- eropple 12y ago
  For your use case, maybe, but "halfway through" for much of what I use my Sous Vide Supreme for would be three or four hours. And I rarely have mine at 80C - I do beef at 55-57C, and there are safety implications (or quality implications, in the other direction) to not maintaining temperature.
- tptacek 12y ago
  That works fine for short cooks and for the most forgiving proteins, but it does not work well for long cooks, braise cuts, vegetables, or high-temp proteins (like confit). It's also much less convenient; you can bag proteins and dunk them in the circulator in the morning and sear them when you get home from work.
blackdogie 12y ago
Looks great. I guess this would be a great time to think of maybe trying your luck with Kickstarter (that is if you are interested in continuing working with such hardware). Either way a nice write up for a cool little project !
- tptacek 12y ago
  His BOM is just ~$60 off Sansaire's retail price, which is an integrated circulator with performance near Polyscience's. This is a bad idea for a Kickstarter: there is already an open price war between commercial-quality circulators. They'll be under $100 within the next couple years (it's just not that expensive to produce them.)
NoNotTheDuo 12y ago
I'd be curious to know how much the temperature fluctuates and what the average temperature is, plotted against the target. A simple on/of setup like this is much less complicated than a PID setup, but in my experience, the PID code would allow for a much more accurate temperature to be maintained.
- arbesfeld 12y ago
  In larger baths of water (I am using a half-filled 4.75 gallon container), the temperature only fluctuates ~0.25C from the setpoint, as measured by the sensor. I think the large quantity of water makes the change in temperature very gradual.
  - jnellis 12y ago
    Your sensor says it's error is 0.5C. How was calibration done?
bitroliest 12y ago
Not directly related to the tech, but "sealing in the juices" with a sear is broscience. [1] http://www.seriouseats.com/2009/12/the-food-lab-how-to-cook-roast-a-perfect-prime-rib.html?ref=search http://www.seriouseats.com/2009/12/the-food-lab-how-to-cook-...
- ghostDancer 12y ago
  From the same page a cheap sous-vide hack: http://www.seriouseats.com/2010/04/cook-your-meat-in-a-beer-cooler-the-worlds-best-sous-vide-hack.html http://www.seriouseats.com/2010/04/cook-your-meat-in-a-beer-...
  - joezydeco 12y ago
    That's good for a 1-hour steak, but I wouldn't do eggs this way (needs more precise temp) or a 72-hour short rib braise (needs stable heat for longer).
    - jpp 12y ago
      I agree--and even for one hour timeframes, be sure to check your ending temperature to make sure it didn't cool off too much. I'm not a fan of the beer-cooler method for this reason (although with care, of course, it's safe).
- scott_karana 12y ago
  "Sealing in the juices" is definitely false, but a hot sear to cause the Maillaird protein reaction is important if you want to have the distinctive "traditional" steak taste.
  - joshu 12y ago
    The more important question for sous vide: Sear before or after vacuuming? Or both?
    - alilja 12y ago
pepon 12y ago
food + heat + plastics doesn't sound very appealing...
- budgi3 12y ago
  This is what is holding me back on getting into sous vide. Any non plastic alternatives?
  - scarboy 12y ago
    You can use mason jars if you are worried about plastic.
    - tptacek 12y ago
      That works for things that perfectly fill a mason jar, but not well otherwise; the giant air pockets are an issue.
      - scarboy 12y ago
        I completely agree, I'm just stating the alternative. Sometimes standard freezer ziploc bags aren't even big enough. I was doing a large prime rib a while ago and has to use the larger size freezer bags that aren't normally available at my grocery store. If you used something else you would need a large amount of butter/liquid to get rid of the air.
      - jpp 12y ago
        I find it generally easier to cut items into portion sizes before cooking them sous vide. - It makes the size more manageable in your water bath. - You don't have to worry as much about temperature ramp-up time between outer surface and core of food item. - For delicate proteins, means there's less handling of the item post-cooking. -Jeff
      - eropple 12y ago
        You can get differently-sized jars, though. I've got a pretty wide variety of sizes for different stuff. I still use bags most of the time, because I don't think running a cooker at 55 deg C with bags rated for 90 deg C is going to be an issue.
joezydeco 12y ago
I'm curious to see a graph of actual temperature vs setpoint. You're doing basic bang-bang control with a bunch of immersion heaters that get hot VERY quickly. And, dude, make that thing a little safer. Fuse your AC supply. Use real crimped terminal connectors. Put a safety enclosure around those immersion heaters or at least get them farther away from the wall of your chamber. Find a better way to secure them than electrical tape. And for $100 you can get a Dorkfood DSV from Amazon that will (safely) PID-control a $10 crockpot. So there are cheaper alternatives than what you have found.
- tdicola 12y ago
  Agreed on the safety concerns, but I think the point of the project was learning, not saving money.
surement 12y ago
This is a nice project but this common misconception is false: > Searing the food after sous-vide seals in the juices http://www.foodnetwork.com/videos/to-sear-or-not-to-sear-98517.html http://www.foodnetwork.com/videos/to-sear-or-not-to-sear-985...
- tptacek 12y ago
  You definitely want to sear though, both before and after (Kenji Alt is wrong about this). For flavor.
  - SoftwareMaven 12y ago
    I'm dubious about searing it twice; it's something I've never seen mentioned in the reading I've done on slow, temperature-controled cooking. It seems like it would just dry out the edges, making them leathery; however, I'm willing to be educated otherwise in the effort to make a great steak.
    - tptacek 12y ago
      The pre-sear (which can be lighter than the post-sear) adds flavor, but also makes the (important) post-sear much faster, which also minimizes the degree to which the post-sear will raise the interior temperature of your protein. The pre-sear is especially important with long cooks, because it kills surface bacteria. The first time you get too much lactobacillus hitching a ride on your short ribs will be the last time you skip out on the pre-sear. (Lacto isn't dangerous; after all, the protein is pasteurized in the bath, but the final product will smell awful). I'm not sure what you mean by "drying out the edges, making them leathery". I think I can just say "no" on that.
      - threeways 12y ago
        The lacto explosion is way more likely to happen when your meat is grossly under-seasoned going into the bag. Which is probably the most made mistake by home cooks. I cooked in New York City during the years that sous-vide became legal. I worked at the restaurant that received the first sous-vide permit from the health department, and later at other Michelin starred restaurants that did sous-vide. That of course doesn't give me authority, but I do have a perspective on what the best professionals do. For meat, salt aggressively going into the bag, and lightly coming out of the bag. Sear once :-) (As an aside, since I'm already talking to you. You're one of my favorite commenters here on HN, and one of the reasons I don't skip the comments section entirely.)
nbardy 12y ago
I'm curious on some numbers on how this performs compared to the commercial units the expensive food industry models and the new kick starter wave. Something like this could be really neat since it is versatile and you could use it to heat/cool other things. Thinking about food the first time to mind would be temperature control for charcuterie and cheeses.
- tptacek 12y ago
  People already do stuff like this with PID-controlled temp and humidity, both for curing meat and for barbecue. Auber Instruments makes controllers designed for it, and they're pretty cheap.
- arbesfeld 12y ago
  Exactly. This is really a general purpose temperature-controlling device (as opposed to the hyper-specific commercial hardware). I'm hoping to incorporate the same design into a smoker and refrigeration unit.
dpeck 12y ago
Great writeup, but we're probably past the point of DIY sous-vide systems being anything more than weekend hacker project for funsies. I just picked up an anova a few months ago (was $169 on sale) and for that price you need to be getting a lot of enjoyment out of the build process and be happy having an inferior product at the end. http://smile.amazon.com/Anova-Sous-Vide-Immersion-Circulator/dp/B00GT753W8/ref=sr_1_1?ie=UTF8&qid=1418667231&sr=8-1&keywords=nova+sous+vide http://smile.amazon.com/Anova-Sous-Vide-Immersion-Circulator...
bizzleDawg 12y ago
My friend did a DIY Sous-vide towards the end of last year, no android app, but has a simple UI for set point and tuning. He actually made it a mains plug pass through (UK version) so that you can use it with a traditional slow cooker for some temperatures etc. Blog link: http://rfwebb.com/projects/sous-vide-part-2/ http://rfwebb.com/projects/sous-vide-part-2/ Extra pictures (Skip all the PCB ones): http://imgur.com/a/aG1Jp http://imgur.com/a/aG1Jp Edit: source code: https://github.com/bitdivision/sous-vide https://github.com/bitdivision/sous-vide
tgb 12y ago
Sous-vide is interesting to me but only seems worth it if you eat a lot of meat. Am I mistaken?
- ghaff 12y ago
  You're not really mistaken. You can do some interesting things with eggs--very precisely control the texture of both the white and the yolk (which relates to the coagulation of different proteins). But, for the most part, I use sous vide for meat and, especially, red meat. I'm not sure I'd say you need to eat a "lot" of meat (it's not like I use my sous vide setup every few days) but it is primarily for meat.
  - tptacek 12y ago
    It works really well with chicken thighs, too. :)
    - ghaff 12y ago
      I must say that I've never tried it with chicken thighs. I do use it with boneless breasts now and then for when I want some cooked chicken for a salad or noodle dish. It really helps keep the meat nice and moist while being cooked just right.
- rcoder 12y ago
  Like traditional BBQ (e.g., low-and-slow cooking over coals) sous vide is most interesting when applied to meat, especially cheaper cuts that would normally have to get boiled, braised, or roasted to within an inch of inedibility before being soft enough to eat. That being said, my absolute favorite thing to prepare sous vide is carrots. Lots of other root vegetables (turnips, burdock, sunchokes, new potatoes) can similarly be cooked in a water bath to a temperature just high enough to soften them without extracting flavor or nutrients via boiling, steaming, or sautéing. I've also had good luck with green beans, asparagus, and broccoli rabe. Finally, if you're pescetarian seafood is also a great option. I'm not sure I'll ever cook lobster any other way after seeing what whole (shell-on) lobster tails are like cooked sous vide with a healthy dollop of butter.
legohead 12y ago
I've done some sous-vide after watching Chef Steps[1] on youtube. I just used a water thermometer and ziplock bags, which they have some examples of in their videos. My smallest stove top burner at its lowest setting gets water up to 117F. The salmon video they had the temp at 109, but I tried it anyway. It turned out amazing - I'd definitely do it again. I also tried steak, but bought a cheap cut, and it turned out really good as well. I turned the burner up to 2.5 which got the water temp to around 135F. I'm so happy with my results I'm looking at purchasing a real sous-vide heater. Sous-vide definitely has a bright future. [1]: https://www.youtube.com/user/chefsteps https://www.youtube.com/user/chefsteps
- eropple 12y ago
  I have a Sous Vide Supreme[1] and it's pretty much the secret weapon for making cheap beef tasty. Even cheapo chuck can do really well in one of them if you let them go for a while. What's nerdy-cool about it, I think, is that if you're quick, you can seal a steak with no air bubbles whatsoever and the steak will remain bright red while it cooks. Obviously you sear it after, but watching people's eyes bug out a little when they see the bright red slab of perfectly tasty and cooked meat come out of the pot is kind of amazing. [1] - I also have an Anova, and if you can swing it I much prefer the SVS; with the Anova the temperature gradient can be pretty wide in larger containers, and you don't have to be nearly as careful about how you place stuff in the SVS.
  - tptacek 12y ago
    Really? You're getting better performance from an SVS than an Anova? My understanding is that for reasonable water baths, the Anova is pretty close to the performance of the Polyscience, which is the gold standard. When Kenji Alt tested the Anova, he found his unit had been miscalibrated; maybe check yours? I donated my unopened Sansaire to Butcher & Larder and the first thing they did with it was set it up in a huge water bath to cook a bunch of huge mortadella. It took them forever to get the bath up to temp, so long that I thought something might have been wrong with the unit. I think the fix was to cover the bath to eliminate evaporative cooling. That is also a problem the SVS doesn't have, being a closed bath. But the circulator should be more flexible and, from what I understand, higher performance. If you're willing to spring for the SVS, a better rec might be to go for the mid-range Polyscience (the CS).
scott_karana 12y ago
> An average sous-vide cooker costs $2000, with low-end cookers going for around $300 Seems a bit exaggerated, and I'm not sure why, when this article was pretty awesome otherwise. The professional-grade, ubiquitous Polyscience MX units are around ~$1000[1][2], and the low-end cookers start at $180-200[1][2]... 1 http://www.amazon.com/MX-Immersion-Circulator-C-Clamp/dp/B007PB9DLO http://www.amazon.com/MX-Immersion-Circulator-C-Clamp/dp/B00... 2 https://www.instrumart.com/products/37038/polyscience-mx-immersion-circulator https://www.instrumart.com/products/37038/polyscience-mx-imm... 3 http://anovaculinary.com/pages/products http://anovaculinary.com/pages/products 4 http://sansaire.com/shop/ http://sansaire.com/shop/
- tptacek 12y ago
  It is way, way exaggerated. Even the professional Polyscience (the one I see in restaurant kitchens) only costs ~$800. HN'ers shouldn't pay anything like that: the current price point for consumer home circulators (the only kind you should get, like the Anova or Nomiku or Sansaire) is ~$160.
  - nappy-doo 12y ago
    I was on the design team for the PS machines. (I say design team, I mean it was three people in a room for the whole thing [circuits/software/mechanical design].) The main advantages of a high end machine are more accurate control (small advantage) and circulation (big advantage). The linked article's control algorithm is primitive (to say the least), and probably only marginally maintains set temp. The PS machines are accurate to < 0.01 degree (which for food doesn't matter), but the control software is the same between the food machines, and high end chemistry equipment.
    - jimmaswell 12y ago
      As far as I can tell, some small waterproof fans would be more than enough for sufficient circulation. Why is that a specific advantage of high-end ones?
      - 12y ago
vkatluri 12y ago
This seems like a whole lot less effort and simpler design (of course without the Bluetooth control). If some one is looking for a cheaper entry point, this is great: http://www.instructables.com/id/Sous-vide-cooker-for-less-than-40/ http://www.instructables.com/id/Sous-vide-cooker-for-less-th...
timinman 12y ago
"Tape served as a lever for positioning the chip."
abakker 12y ago
Or, instead of writing temperature control logic yourself, you can buy a really cheap PID. There are nuances to good temperature control that warrant using chips that optimize for the environment they are heating. http://www.instructables.com/id/Sous-vide-cooker-for-less-than-40/?ALLSTEPS http://www.instructables.com/id/Sous-vide-cooker-for-less-th... Also, a PID is not a thermostat - http://en.wikipedia.org/wiki/PID_controller http://en.wikipedia.org/wiki/PID_controller I'm sure that in water, a simple thermostat can be good enough, but its probably still best to have a controller that optimizes for its environment. A major point of sous vide is that the cooking temperature is very close to the minimum pasteurization temperatures. Cooking steak at 137 degrees requires that you are SURE it actually cooked at 137 for the amount of time you specified. Also, 90 minutes for a steak is insufficient at 56°c http://www.polyscienceculinary.com/blog/food-safety-with-sous-vide-cooking/ http://www.polyscienceculinary.com/blog/food-safety-with-sou...
- arbesfeld 12y ago
  Great points, I do think that a professional PID is a better and more efficient way to build a sous-vide. I wanted to build something from basic components instead as part of the learning process, and also to allow me customize the logic via Bluetooth. Regarding the steak, I find that a 1 inch thick steak only takes ~45 minutes to reach the target internal temperature. This scales dramatically as the steak thickness is increased, however.
  - abakker 12y ago
    because the temperatures inside are below instant pasteurization temperatures (158°F) though, reaching the target is insufficient. They need to be held at the target temperature over a period of time to guarantee sufficient pasteurization. I'll also agree that the learning process can't be beat the way you did it. I suppose you could simulate the PID function in software on the arduino though - http://playground.arduino.cc/Code/PIDLibrary http://playground.arduino.cc/Code/PIDLibrary
    - jwr 12y ago
      Be careful with Arduino libraries. If you are trying to learn something, it's usually better to write your own, or look at really good code. Case in point, PIDLibrary, I'm looking at the PIDCompute function, line 57: ITerm+= (ki * error); That's not how you deal with I. You are supposed to accumulate (integrate) the error and multiply by Ki only for the final PID addition. You don't want to accumulate your errors multiplied each time by Ki, it makes no sense.
gitpusher 12y ago
Great project, and great write-up. But most people don't have access to a 3D printer... which significantly changes the effective "cost" for such folks. Still, thanks for sharing! Hope you enjoy all of that perfectly-cooked food :)
- stephen_g 12y ago
  What's to stop somebody putting it in a $5 pre-made plastic box that you can find at any electronics store?
arbesfeld 12y ago
Hi! Original poster here. I built this as part of the "How to Make Almost Anything" class at MIT (http://fab.cba.mit.edu/classes/863.14/ http://fab.cba.mit.edu/classes/863.14/). This was more of a weekend hack for fun than a money-saving project. Thanks for all of the advice and comments!
- tptacek 12y ago
  It's a great writeup!
  - blhack 12y ago
    I've seen you comment a lot on sous vide in the past, is there a specific machine that you recommend? (And then is there one you'd recommend if money was no object)
    - tptacek 12y ago
      Whichever of Anova, Sansaire, and Polyscience is cheapest at the time.
      - deleted 12y ago
        [deleted]
    - _pius 12y ago
      I own the Sansaire, but right now I'd recommend the new Anova one that comes with an app and is well-reviewed by Serious Eats. http://anovaculinary.com/products/anova-precision-cooker http://anovaculinary.com/products/anova-precision-cooker http://www.seriouseats.com/2014/05/new-anova-precision-cooker-best-cheapest-sous-vide-circulator-on-the-market.html http://www.seriouseats.com/2014/05/new-anova-precision-cooke...
      - mikecb 12y ago
        Do you know if they've released the android app yet? You can use it without (has a little wheel to set temp), but the monitoring and timing obviously don't work.
tzs 12y ago
I have a couple of questions about the schematic. R4 and R5 are 0K resistors. 0K resistors actually exist, and are typically used in place of short pieces of wire. The advantage of a 0K resistor over a short piece of wire is that they can be picked and placed and soldered using the same equipment that handles resistors, thus saving the need of having a separate machine for short wires. That is how they are being used here, as you can see from the layout diagram. R5 is used to carry the RST signal over another line on the board, and R4 serves the same function for VCC. First question: should these even be included on the schematic? They only exist to work around a construction limitation due to the use of a single layer PCB. If the circuit was built on a two layer PCB, or a breadboard, or wire wrapped, there would be no 0K resistors needed. I thought that schematics were supposed to just convey the topology of the circuit, leaving things related to the practical difficulties of construction to other documents (like the layout diagram). Second question: on the schematic, why is R5 shown as connecting RST to RST, but R4 is shown as connecting VCC to itself? They are both being used to take a line across another line, so why aren't the both drawn the same way on the schematic?
- arbesfeld 12y ago
  Great questions. As you point out, I'm using the 0K resistors as jumper wires. It's a one-sided board so the 0K resistors basically act as a second layer on the board. Regarding your first question, I am not sure how to place a component only on the layout diagram. This would be ideal, because the 0K resistors really shouldn't be encoded in the schematic. I agree with your second point -- it's just an inconsistency in my schematic!
- vonmoltke 12y ago
  A 0 ohm resistor typically is only used for places where a different-valued resistor could be substituted or used to exist, or to act as an optional jumper on different revisions of hardware. In those cases, the resistor is in the schematics. A circuit designed from the start with a 0 ohm resistor that was just used for connecting two points across some board feature would never make it past review where I used to work. Such a situation may come up due to later design changes or board damage, in which case the board is modified by use of a "blue wire", which is an actual blue-insulated wire that makes a point-to-point connection on the surface of the board. Those are not in the schematic. That said, I used to work on military electronics. Perhaps the consumer electronics world is different.
cnvogel 12y ago
Hey arbesfeld, I really like that project, and the nice writeup really presents it well. But especially as people might use it for inspiration for their own temperature-controlled cooking projects, I think the lack of a proper isolation of the mains-powered parts is a little bit worrying. For the next project, or maybe as advice to the random person looking at the HN comments, here's what I normally do: Try to minimize the area of unisolated conductors in devices on which you work. If I solder cables to e.g. a mains inlet, I'd put heat-shrink-tubing over it, so that it's not touchable anymore. Or use the proper crimped terminations, which also are available in isolated versions. https://www.google.de/search?q=flachstecker&tbm=isch https://www.google.de/search?q=flachstecker&tbm=isch To protect braided wire, and make the connections more reliable over time, I like to use "wire termination" (I don't know the correct english term, in Germany we call them Aderendhülse (literally: conductor end sheath). https://www.google.de/search?q=aderendhülse&tbm=isch https://www.google.de/search?q=aderendhülse&tbm=isch Instead of these "screw on caps" for cables, try to find suitable terminal blocks. If you have the possibility to access a 3D printer, make a small clip that goes over the screw-terminals of the solid-state relay. If possible, try to have a "high-voltage" and a "low voltage" side in your enclosure, that way, you are even less likely to come in contact with mains voltage while working e.g. on the MCU part (connecting/disconnecting the programming cable). I'd like to stress again: I really like your project as presented, I only want to show some ways in which the project could serve maybe as a inspiration also to safe mains-powered electronic design.
- austinz 12y ago
  I really like this comment. It's kind and encouraging, providing actionable and constructive advice even while pointing out a rather serious flaw.
- arbesfeld 12y ago
  Thanks for the tips. This was my first time working with power components and I wasn't familiar with most of these parts. I'll incorporate these suggestions into the blog post so that they can be a resource to others.
  - mikeytown2 12y ago
jedrek 12y ago
Shouldn't water be flowing in a good sous vide cooker to maintain even temperature throughout or am I talking out my butt?
- calbear81 12y ago
  I think you are correct, the commercial models are marketed as circulators so they have both the heating element and a way to move water around to ensure even temperatures throughout the water tub.
- arbesfeld 12y ago
  Yes, that is correct. I used an aquarium circulation pump for this (http://fab.cba.mit.edu/classes/863.14/people/matthew_arbesfeld/img/final/final_cooking_eggs.jpg http://fab.cba.mit.edu/classes/863.14/people/matthew_arbesfe...). They go for about 10 bucks on Amazon.
  - jedrek 12y ago
    Ah, I skimmed the article but didn't notice that. Thanks for your reply :)
ojiikun 12y ago
Pedantic: you built a really cool PID-controlled immersion heater, not a "sous vide cooker". Sous vide is the technique of preparing food in a vacuum. Placing food in a zip-top bag and displacing the air out might give you a reasonable water-product interaction surface, but it does not form a vacuum, and therefore is not cooking en sous vide.
- joshu 12y ago
  Even more pedantic: The cooker doesn't generate the vacuum. You use an immersion heater to cook the things in the bags. It's also generally thought you don't really need to bother with actual vacuum for meats anyway.
ha292 12y ago
Question for sous-vide aficianados. Are you not worried about the chemicals going from plastic to your feed ? I grew up knowing that, by and large, the less manufactured stuff you put in your food the better the food is for your body. So, it seems highly dangerous to me to take natural piece of food, wrap it in a highly complex chemical compound (plastic), heat it, and then consume it.
- lee 12y ago
  I don't know much about sous-vide, but the cooking temperature is 55 to 60 degrees celsius. That's fairly low. Most plastics shouldn't deteriorate at that temperature.
- maratd 12y ago
  Most of the time the food came in that very plastic. I mostly sous-vide meat that came frozen and is already vacuum sealed. One less step. You're generally heating it to 140 F or so. I don't know if that's sufficient to trigger leaching of some sort, but the plastic isn't deformed in any way and there's no aftertaste. Any experts care to weigh in?
  - ha292 12y ago
    Is there any scientific evidence for this statement on no harmful chemical transfer below 140F. Also, just because the food came in the very bag you're cooking it in doesn't mean it is safer.
    - maratd 12y ago
      > Is there any scientific evidence for this statement on no harmful chemical transfer below 140F. I didn't make that statement. I simply stated that was my practice. If you have evidence that it is harmful, I would certainly like to know. > Also, just because the food came in the very bag you're cooking it in doesn't mean it is safer. Absolutely. There is no evidence that it doesn't leach at room temperature. Should we stop buying all food packaged in plastics? That's a tall order. Many vegetables come in plastics now and those that don't, you'll likely put in a plastic bag either in the grocery store or as you're leaving it. Do you have evidence that any of this is harmful? Genuinely want to know.
StavrosK 12y ago
I love the "cost" table. Having recently built a mobile phone out of a rotary phone (https://www.youtube.com/watch?v=fSkdWQswpc8 https://www.youtube.com/watch?v=fSkdWQswpc8), my costs look something like those, except: Cost of materials: $50 Time cost: $1500 Then again, it is a prototype, which has to go with all the fixed costs, but to say that this cooker only cost $X isn't entirely accurate.
bliker 12y ago
I was wondering why there is a need to involve a micro-controller? I can see this project being done with couple of op-amps and potentiometer? I see so many hobby project using arduinos for no good reason. Please people show some love for analog electronics!
- pbhjpbhj 12y ago
  >why there is a need to involve a micro-controller? // Easiest way to implement bluetooth?
- ajcarpy2005 12y ago
  Bluetooth controller
pbhjpbhj 12y ago
The point of sous-vide is [primarily] to break down proteins in meat? Presumably then you can freeze the meat or refrigerate and simply re-heat/sear at a later time? Under this assumption are any stores offering pre-sous-vide meats?
Loic 12y ago
For the readers, this is not a "sous-vide" cooker, only a temperature controlled immersion cooker. "Sous-vide" means "in vacuum" and usually you combine low temperature controlled long time cooking with low pressure. A book from Thomas Keller about sous vide cooking: http://www.amazon.com/Under-Pressure-Cooking-Sous-Vide/dp/1579653510 http://www.amazon.com/Under-Pressure-Cooking-Sous-Vide/dp/15...

194 points by arbesfeld 12y ago

andr 12y ago

I've never understood the need for a complicated sous-vide setup. I've found that water at 80 degrees Celsius in a heavy pot with the lid on will remain sufficiently hot for 30-45 minutes. If not, you can always swap the water halfway through.

NoNotTheDuo 12y ago
I have one created using an Arduino and a Crockpot. The biggest thing for me is that I can throw some steaks in at 730am when I leave for work and when I get home at 530pm they are ready to eat (or sear-then-eat, I guess). I think it's the same argument as why you would want a crockpot in your kitchen, versus a normal pot.
eropple 12y ago
For your use case, maybe, but "halfway through" for much of what I use my Sous Vide Supreme for would be three or four hours. And I rarely have mine at 80C - I do beef at 55-57C, and there are safety implications (or quality implications, in the other direction) to not maintaining temperature.
tptacek 12y ago
That works fine for short cooks and for the most forgiving proteins, but it does not work well for long cooks, braise cuts, vegetables, or high-temp proteins (like confit). It's also much less convenient; you can bag proteins and dunk them in the circulator in the morning and sear them when you get home from work.

blackdogie 12y ago

Looks great. I guess this would be a great time to think of maybe trying your luck with Kickstarter (that is if you are interested in continuing working with such hardware). Either way a nice write up for a cool little project !

tptacek 12y ago
His BOM is just ~$60 off Sansaire's retail price, which is an integrated circulator with performance near Polyscience's. This is a bad idea for a Kickstarter: there is already an open price war between commercial-quality circulators. They'll be under $100 within the next couple years (it's just not that expensive to produce them.)

NoNotTheDuo 12y ago

I'd be curious to know how much the temperature fluctuates and what the average temperature is, plotted against the target. A simple on/of setup like this is much less complicated than a PID setup, but in my experience, the PID code would allow for a much more accurate temperature to be maintained.

arbesfeld 12y ago
In larger baths of water (I am using a half-filled 4.75 gallon container), the temperature only fluctuates ~0.25C from the setpoint, as measured by the sensor. I think the large quantity of water makes the change in temperature very gradual.
- jnellis 12y ago
  Your sensor says it's error is 0.5C. How was calibration done?

bitroliest 12y ago

Not directly related to the tech, but "sealing in the juices" with a sear is broscience. [1] http://www.seriouseats.com/2009/12/the-food-lab-how-to-cook-roast-a-perfect-prime-rib.html?ref=search http://www.seriouseats.com/2009/12/the-food-lab-how-to-cook-...

ghostDancer 12y ago
From the same page a cheap sous-vide hack: http://www.seriouseats.com/2010/04/cook-your-meat-in-a-beer-cooler-the-worlds-best-sous-vide-hack.html http://www.seriouseats.com/2010/04/cook-your-meat-in-a-beer-...
- joezydeco 12y ago
  That's good for a 1-hour steak, but I wouldn't do eggs this way (needs more precise temp) or a 72-hour short rib braise (needs stable heat for longer).
  - jpp 12y ago
    I agree--and even for one hour timeframes, be sure to check your ending temperature to make sure it didn't cool off too much. I'm not a fan of the beer-cooler method for this reason (although with care, of course, it's safe).
scott_karana 12y ago
"Sealing in the juices" is definitely false, but a hot sear to cause the Maillaird protein reaction is important if you want to have the distinctive "traditional" steak taste.
- joshu 12y ago
  The more important question for sous vide: Sear before or after vacuuming? Or both?
  - alilja 12y ago

pepon 12y ago

food + heat + plastics doesn't sound very appealing...

budgi3 12y ago
This is what is holding me back on getting into sous vide. Any non plastic alternatives?
- scarboy 12y ago
  You can use mason jars if you are worried about plastic.
  - tptacek 12y ago
    That works for things that perfectly fill a mason jar, but not well otherwise; the giant air pockets are an issue.
    - scarboy 12y ago
      I completely agree, I'm just stating the alternative. Sometimes standard freezer ziploc bags aren't even big enough. I was doing a large prime rib a while ago and has to use the larger size freezer bags that aren't normally available at my grocery store. If you used something else you would need a large amount of butter/liquid to get rid of the air.
    - jpp 12y ago
      I find it generally easier to cut items into portion sizes before cooking them sous vide. - It makes the size more manageable in your water bath. - You don't have to worry as much about temperature ramp-up time between outer surface and core of food item. - For delicate proteins, means there's less handling of the item post-cooking. -Jeff
    - eropple 12y ago
      You can get differently-sized jars, though. I've got a pretty wide variety of sizes for different stuff. I still use bags most of the time, because I don't think running a cooker at 55 deg C with bags rated for 90 deg C is going to be an issue.

joezydeco 12y ago

I'm curious to see a graph of actual temperature vs setpoint. You're doing basic bang-bang control with a bunch of immersion heaters that get hot VERY quickly. And, dude, make that thing a little safer. Fuse your AC supply. Use real crimped terminal connectors. Put a safety enclosure around those immersion heaters or at least get them farther away from the wall of your chamber. Find a better way to secure them than electrical tape. And for $100 you can get a Dorkfood DSV from Amazon that will (safely) PID-control a $10 crockpot. So there are cheaper alternatives than what you have found.

tdicola 12y ago
Agreed on the safety concerns, but I think the point of the project was learning, not saving money.

surement 12y ago

This is a nice project but this common misconception is false: > Searing the food after sous-vide seals in the juices http://www.foodnetwork.com/videos/to-sear-or-not-to-sear-98517.html http://www.foodnetwork.com/videos/to-sear-or-not-to-sear-985...

tptacek 12y ago
You definitely want to sear though, both before and after (Kenji Alt is wrong about this). For flavor.
- SoftwareMaven 12y ago
  I'm dubious about searing it twice; it's something I've never seen mentioned in the reading I've done on slow, temperature-controled cooking. It seems like it would just dry out the edges, making them leathery; however, I'm willing to be educated otherwise in the effort to make a great steak.
  - tptacek 12y ago
    The pre-sear (which can be lighter than the post-sear) adds flavor, but also makes the (important) post-sear much faster, which also minimizes the degree to which the post-sear will raise the interior temperature of your protein. The pre-sear is especially important with long cooks, because it kills surface bacteria. The first time you get too much lactobacillus hitching a ride on your short ribs will be the last time you skip out on the pre-sear. (Lacto isn't dangerous; after all, the protein is pasteurized in the bath, but the final product will smell awful). I'm not sure what you mean by "drying out the edges, making them leathery". I think I can just say "no" on that.
    - threeways 12y ago
      The lacto explosion is way more likely to happen when your meat is grossly under-seasoned going into the bag. Which is probably the most made mistake by home cooks. I cooked in New York City during the years that sous-vide became legal. I worked at the restaurant that received the first sous-vide permit from the health department, and later at other Michelin starred restaurants that did sous-vide. That of course doesn't give me authority, but I do have a perspective on what the best professionals do. For meat, salt aggressively going into the bag, and lightly coming out of the bag. Sear once :-) (As an aside, since I'm already talking to you. You're one of my favorite commenters here on HN, and one of the reasons I don't skip the comments section entirely.)

nbardy 12y ago

I'm curious on some numbers on how this performs compared to the commercial units the expensive food industry models and the new kick starter wave. Something like this could be really neat since it is versatile and you could use it to heat/cool other things. Thinking about food the first time to mind would be temperature control for charcuterie and cheeses.

tptacek 12y ago
People already do stuff like this with PID-controlled temp and humidity, both for curing meat and for barbecue. Auber Instruments makes controllers designed for it, and they're pretty cheap.
arbesfeld 12y ago
Exactly. This is really a general purpose temperature-controlling device (as opposed to the hyper-specific commercial hardware). I'm hoping to incorporate the same design into a smoker and refrigeration unit.

dpeck 12y ago

Great writeup, but we're probably past the point of DIY sous-vide systems being anything more than weekend hacker project for funsies. I just picked up an anova a few months ago (was $169 on sale) and for that price you need to be getting a lot of enjoyment out of the build process and be happy having an inferior product at the end. http://smile.amazon.com/Anova-Sous-Vide-Immersion-Circulator/dp/B00GT753W8/ref=sr_1_1?ie=UTF8&qid=1418667231&sr=8-1&keywords=nova+sous+vide http://smile.amazon.com/Anova-Sous-Vide-Immersion-Circulator...

bizzleDawg 12y ago

My friend did a DIY Sous-vide towards the end of last year, no android app, but has a simple UI for set point and tuning. He actually made it a mains plug pass through (UK version) so that you can use it with a traditional slow cooker for some temperatures etc. Blog link: http://rfwebb.com/projects/sous-vide-part-2/ http://rfwebb.com/projects/sous-vide-part-2/ Extra pictures (Skip all the PCB ones): http://imgur.com/a/aG1Jp http://imgur.com/a/aG1Jp Edit: source code: https://github.com/bitdivision/sous-vide https://github.com/bitdivision/sous-vide

tgb 12y ago

Sous-vide is interesting to me but only seems worth it if you eat a lot of meat. Am I mistaken?

ghaff 12y ago
You're not really mistaken. You can do some interesting things with eggs--very precisely control the texture of both the white and the yolk (which relates to the coagulation of different proteins). But, for the most part, I use sous vide for meat and, especially, red meat. I'm not sure I'd say you need to eat a "lot" of meat (it's not like I use my sous vide setup every few days) but it is primarily for meat.
- tptacek 12y ago
  It works really well with chicken thighs, too. :)
  - ghaff 12y ago
    I must say that I've never tried it with chicken thighs. I do use it with boneless breasts now and then for when I want some cooked chicken for a salad or noodle dish. It really helps keep the meat nice and moist while being cooked just right.
rcoder 12y ago
Like traditional BBQ (e.g., low-and-slow cooking over coals) sous vide is most interesting when applied to meat, especially cheaper cuts that would normally have to get boiled, braised, or roasted to within an inch of inedibility before being soft enough to eat. That being said, my absolute favorite thing to prepare sous vide is carrots. Lots of other root vegetables (turnips, burdock, sunchokes, new potatoes) can similarly be cooked in a water bath to a temperature just high enough to soften them without extracting flavor or nutrients via boiling, steaming, or sautéing. I've also had good luck with green beans, asparagus, and broccoli rabe. Finally, if you're pescetarian seafood is also a great option. I'm not sure I'll ever cook lobster any other way after seeing what whole (shell-on) lobster tails are like cooked sous vide with a healthy dollop of butter.

legohead 12y ago

I've done some sous-vide after watching Chef Steps[1] on youtube. I just used a water thermometer and ziplock bags, which they have some examples of in their videos. My smallest stove top burner at its lowest setting gets water up to 117F. The salmon video they had the temp at 109, but I tried it anyway. It turned out amazing - I'd definitely do it again. I also tried steak, but bought a cheap cut, and it turned out really good as well. I turned the burner up to 2.5 which got the water temp to around 135F. I'm so happy with my results I'm looking at purchasing a real sous-vide heater. Sous-vide definitely has a bright future. [1]: https://www.youtube.com/user/chefsteps https://www.youtube.com/user/chefsteps

eropple 12y ago
I have a Sous Vide Supreme[1] and it's pretty much the secret weapon for making cheap beef tasty. Even cheapo chuck can do really well in one of them if you let them go for a while. What's nerdy-cool about it, I think, is that if you're quick, you can seal a steak with no air bubbles whatsoever and the steak will remain bright red while it cooks. Obviously you sear it after, but watching people's eyes bug out a little when they see the bright red slab of perfectly tasty and cooked meat come out of the pot is kind of amazing. [1] - I also have an Anova, and if you can swing it I much prefer the SVS; with the Anova the temperature gradient can be pretty wide in larger containers, and you don't have to be nearly as careful about how you place stuff in the SVS.
- tptacek 12y ago
  Really? You're getting better performance from an SVS than an Anova? My understanding is that for reasonable water baths, the Anova is pretty close to the performance of the Polyscience, which is the gold standard. When Kenji Alt tested the Anova, he found his unit had been miscalibrated; maybe check yours? I donated my unopened Sansaire to Butcher & Larder and the first thing they did with it was set it up in a huge water bath to cook a bunch of huge mortadella. It took them forever to get the bath up to temp, so long that I thought something might have been wrong with the unit. I think the fix was to cover the bath to eliminate evaporative cooling. That is also a problem the SVS doesn't have, being a closed bath. But the circulator should be more flexible and, from what I understand, higher performance. If you're willing to spring for the SVS, a better rec might be to go for the mid-range Polyscience (the CS).

scott_karana 12y ago

> An average sous-vide cooker costs $2000, with low-end cookers going for around $300 Seems a bit exaggerated, and I'm not sure why, when this article was pretty awesome otherwise. The professional-grade, ubiquitous Polyscience MX units are around ~$1000[1][2], and the low-end cookers start at $180-200[1][2]... 1 http://www.amazon.com/MX-Immersion-Circulator-C-Clamp/dp/B007PB9DLO http://www.amazon.com/MX-Immersion-Circulator-C-Clamp/dp/B00... 2 https://www.instrumart.com/products/37038/polyscience-mx-immersion-circulator https://www.instrumart.com/products/37038/polyscience-mx-imm... 3 http://anovaculinary.com/pages/products http://anovaculinary.com/pages/products 4 http://sansaire.com/shop/ http://sansaire.com/shop/

tptacek 12y ago
It is way, way exaggerated. Even the professional Polyscience (the one I see in restaurant kitchens) only costs ~$800. HN'ers shouldn't pay anything like that: the current price point for consumer home circulators (the only kind you should get, like the Anova or Nomiku or Sansaire) is ~$160.
- nappy-doo 12y ago
  I was on the design team for the PS machines. (I say design team, I mean it was three people in a room for the whole thing [circuits/software/mechanical design].) The main advantages of a high end machine are more accurate control (small advantage) and circulation (big advantage). The linked article's control algorithm is primitive (to say the least), and probably only marginally maintains set temp. The PS machines are accurate to < 0.01 degree (which for food doesn't matter), but the control software is the same between the food machines, and high end chemistry equipment.
  - jimmaswell 12y ago
    As far as I can tell, some small waterproof fans would be more than enough for sufficient circulation. Why is that a specific advantage of high-end ones?
    - 12y ago

vkatluri 12y ago

This seems like a whole lot less effort and simpler design (of course without the Bluetooth control). If some one is looking for a cheaper entry point, this is great: http://www.instructables.com/id/Sous-vide-cooker-for-less-than-40/ http://www.instructables.com/id/Sous-vide-cooker-for-less-th...

timinman 12y ago

"Tape served as a lever for positioning the chip."

abakker 12y ago

Or, instead of writing temperature control logic yourself, you can buy a really cheap PID. There are nuances to good temperature control that warrant using chips that optimize for the environment they are heating. http://www.instructables.com/id/Sous-vide-cooker-for-less-than-40/?ALLSTEPS http://www.instructables.com/id/Sous-vide-cooker-for-less-th... Also, a PID is not a thermostat - http://en.wikipedia.org/wiki/PID_controller http://en.wikipedia.org/wiki/PID_controller I'm sure that in water, a simple thermostat can be good enough, but its probably still best to have a controller that optimizes for its environment. A major point of sous vide is that the cooking temperature is very close to the minimum pasteurization temperatures. Cooking steak at 137 degrees requires that you are SURE it actually cooked at 137 for the amount of time you specified. Also, 90 minutes for a steak is insufficient at 56°c http://www.polyscienceculinary.com/blog/food-safety-with-sous-vide-cooking/ http://www.polyscienceculinary.com/blog/food-safety-with-sou...

arbesfeld 12y ago
Great points, I do think that a professional PID is a better and more efficient way to build a sous-vide. I wanted to build something from basic components instead as part of the learning process, and also to allow me customize the logic via Bluetooth. Regarding the steak, I find that a 1 inch thick steak only takes ~45 minutes to reach the target internal temperature. This scales dramatically as the steak thickness is increased, however.
- abakker 12y ago
  because the temperatures inside are below instant pasteurization temperatures (158°F) though, reaching the target is insufficient. They need to be held at the target temperature over a period of time to guarantee sufficient pasteurization. I'll also agree that the learning process can't be beat the way you did it. I suppose you could simulate the PID function in software on the arduino though - http://playground.arduino.cc/Code/PIDLibrary http://playground.arduino.cc/Code/PIDLibrary
  - jwr 12y ago
    Be careful with Arduino libraries. If you are trying to learn something, it's usually better to write your own, or look at really good code. Case in point, PIDLibrary, I'm looking at the PIDCompute function, line 57: ITerm+= (ki * error); That's not how you deal with I. You are supposed to accumulate (integrate) the error and multiply by Ki only for the final PID addition. You don't want to accumulate your errors multiplied each time by Ki, it makes no sense.

gitpusher 12y ago

Great project, and great write-up. But most people don't have access to a 3D printer... which significantly changes the effective "cost" for such folks. Still, thanks for sharing! Hope you enjoy all of that perfectly-cooked food :)

stephen_g 12y ago
What's to stop somebody putting it in a $5 pre-made plastic box that you can find at any electronics store?

arbesfeld 12y ago

Hi! Original poster here. I built this as part of the "How to Make Almost Anything" class at MIT (http://fab.cba.mit.edu/classes/863.14/ http://fab.cba.mit.edu/classes/863.14/). This was more of a weekend hack for fun than a money-saving project. Thanks for all of the advice and comments!

tptacek 12y ago
It's a great writeup!
- blhack 12y ago
  I've seen you comment a lot on sous vide in the past, is there a specific machine that you recommend? (And then is there one you'd recommend if money was no object)
  - tptacek 12y ago
    Whichever of Anova, Sansaire, and Polyscience is cheapest at the time.
    - deleted 12y ago
      [deleted]
  - _pius 12y ago
    I own the Sansaire, but right now I'd recommend the new Anova one that comes with an app and is well-reviewed by Serious Eats. http://anovaculinary.com/products/anova-precision-cooker http://anovaculinary.com/products/anova-precision-cooker http://www.seriouseats.com/2014/05/new-anova-precision-cooker-best-cheapest-sous-vide-circulator-on-the-market.html http://www.seriouseats.com/2014/05/new-anova-precision-cooke...
    - mikecb 12y ago
      Do you know if they've released the android app yet? You can use it without (has a little wheel to set temp), but the monitoring and timing obviously don't work.

tzs 12y ago

I have a couple of questions about the schematic. R4 and R5 are 0K resistors. 0K resistors actually exist, and are typically used in place of short pieces of wire. The advantage of a 0K resistor over a short piece of wire is that they can be picked and placed and soldered using the same equipment that handles resistors, thus saving the need of having a separate machine for short wires. That is how they are being used here, as you can see from the layout diagram. R5 is used to carry the RST signal over another line on the board, and R4 serves the same function for VCC. First question: should these even be included on the schematic? They only exist to work around a construction limitation due to the use of a single layer PCB. If the circuit was built on a two layer PCB, or a breadboard, or wire wrapped, there would be no 0K resistors needed. I thought that schematics were supposed to just convey the topology of the circuit, leaving things related to the practical difficulties of construction to other documents (like the layout diagram). Second question: on the schematic, why is R5 shown as connecting RST to RST, but R4 is shown as connecting VCC to itself? They are both being used to take a line across another line, so why aren't the both drawn the same way on the schematic?

arbesfeld 12y ago
Great questions. As you point out, I'm using the 0K resistors as jumper wires. It's a one-sided board so the 0K resistors basically act as a second layer on the board. Regarding your first question, I am not sure how to place a component only on the layout diagram. This would be ideal, because the 0K resistors really shouldn't be encoded in the schematic. I agree with your second point -- it's just an inconsistency in my schematic!
vonmoltke 12y ago
A 0 ohm resistor typically is only used for places where a different-valued resistor could be substituted or used to exist, or to act as an optional jumper on different revisions of hardware. In those cases, the resistor is in the schematics. A circuit designed from the start with a 0 ohm resistor that was just used for connecting two points across some board feature would never make it past review where I used to work. Such a situation may come up due to later design changes or board damage, in which case the board is modified by use of a "blue wire", which is an actual blue-insulated wire that makes a point-to-point connection on the surface of the board. Those are not in the schematic. That said, I used to work on military electronics. Perhaps the consumer electronics world is different.

cnvogel 12y ago

Hey arbesfeld, I really like that project, and the nice writeup really presents it well. But especially as people might use it for inspiration for their own temperature-controlled cooking projects, I think the lack of a proper isolation of the mains-powered parts is a little bit worrying. For the next project, or maybe as advice to the random person looking at the HN comments, here's what I normally do: Try to minimize the area of unisolated conductors in devices on which you work. If I solder cables to e.g. a mains inlet, I'd put heat-shrink-tubing over it, so that it's not touchable anymore. Or use the proper crimped terminations, which also are available in isolated versions. https://www.google.de/search?q=flachstecker&tbm=isch https://www.google.de/search?q=flachstecker&tbm=isch To protect braided wire, and make the connections more reliable over time, I like to use "wire termination" (I don't know the correct english term, in Germany we call them Aderendhülse (literally: conductor end sheath). https://www.google.de/search?q=aderendhülse&tbm=isch https://www.google.de/search?q=aderendhülse&tbm=isch Instead of these "screw on caps" for cables, try to find suitable terminal blocks. If you have the possibility to access a 3D printer, make a small clip that goes over the screw-terminals of the solid-state relay. If possible, try to have a "high-voltage" and a "low voltage" side in your enclosure, that way, you are even less likely to come in contact with mains voltage while working e.g. on the MCU part (connecting/disconnecting the programming cable). I'd like to stress again: I really like your project as presented, I only want to show some ways in which the project could serve maybe as a inspiration also to safe mains-powered electronic design.

austinz 12y ago
I really like this comment. It's kind and encouraging, providing actionable and constructive advice even while pointing out a rather serious flaw.
arbesfeld 12y ago
Thanks for the tips. This was my first time working with power components and I wasn't familiar with most of these parts. I'll incorporate these suggestions into the blog post so that they can be a resource to others.
- mikeytown2 12y ago

jedrek 12y ago

Shouldn't water be flowing in a good sous vide cooker to maintain even temperature throughout or am I talking out my butt?

calbear81 12y ago
I think you are correct, the commercial models are marketed as circulators so they have both the heating element and a way to move water around to ensure even temperatures throughout the water tub.
arbesfeld 12y ago
Yes, that is correct. I used an aquarium circulation pump for this (http://fab.cba.mit.edu/classes/863.14/people/matthew_arbesfeld/img/final/final_cooking_eggs.jpg http://fab.cba.mit.edu/classes/863.14/people/matthew_arbesfe...). They go for about 10 bucks on Amazon.
- jedrek 12y ago
  Ah, I skimmed the article but didn't notice that. Thanks for your reply :)

ojiikun 12y ago

Pedantic: you built a really cool PID-controlled immersion heater, not a "sous vide cooker". Sous vide is the technique of preparing food in a vacuum. Placing food in a zip-top bag and displacing the air out might give you a reasonable water-product interaction surface, but it does not form a vacuum, and therefore is not cooking en sous vide.

joshu 12y ago
Even more pedantic: The cooker doesn't generate the vacuum. You use an immersion heater to cook the things in the bags. It's also generally thought you don't really need to bother with actual vacuum for meats anyway.

ha292 12y ago

Question for sous-vide aficianados. Are you not worried about the chemicals going from plastic to your feed ? I grew up knowing that, by and large, the less manufactured stuff you put in your food the better the food is for your body. So, it seems highly dangerous to me to take natural piece of food, wrap it in a highly complex chemical compound (plastic), heat it, and then consume it.

lee 12y ago
I don't know much about sous-vide, but the cooking temperature is 55 to 60 degrees celsius. That's fairly low. Most plastics shouldn't deteriorate at that temperature.
maratd 12y ago
Most of the time the food came in that very plastic. I mostly sous-vide meat that came frozen and is already vacuum sealed. One less step. You're generally heating it to 140 F or so. I don't know if that's sufficient to trigger leaching of some sort, but the plastic isn't deformed in any way and there's no aftertaste. Any experts care to weigh in?
- ha292 12y ago
  Is there any scientific evidence for this statement on no harmful chemical transfer below 140F. Also, just because the food came in the very bag you're cooking it in doesn't mean it is safer.
  - maratd 12y ago
    > Is there any scientific evidence for this statement on no harmful chemical transfer below 140F. I didn't make that statement. I simply stated that was my practice. If you have evidence that it is harmful, I would certainly like to know. > Also, just because the food came in the very bag you're cooking it in doesn't mean it is safer. Absolutely. There is no evidence that it doesn't leach at room temperature. Should we stop buying all food packaged in plastics? That's a tall order. Many vegetables come in plastics now and those that don't, you'll likely put in a plastic bag either in the grocery store or as you're leaving it. Do you have evidence that any of this is harmful? Genuinely want to know.

StavrosK 12y ago

I love the "cost" table. Having recently built a mobile phone out of a rotary phone (https://www.youtube.com/watch?v=fSkdWQswpc8 https://www.youtube.com/watch?v=fSkdWQswpc8), my costs look something like those, except: Cost of materials: $50 Time cost: $1500 Then again, it is a prototype, which has to go with all the fixed costs, but to say that this cooker only cost $X isn't entirely accurate.

bliker 12y ago

I was wondering why there is a need to involve a micro-controller? I can see this project being done with couple of op-amps and potentiometer? I see so many hobby project using arduinos for no good reason. Please people show some love for analog electronics!

pbhjpbhj 12y ago
>why there is a need to involve a micro-controller? // Easiest way to implement bluetooth?
ajcarpy2005 12y ago
Bluetooth controller

pbhjpbhj 12y ago

The point of sous-vide is [primarily] to break down proteins in meat? Presumably then you can freeze the meat or refrigerate and simply re-heat/sear at a later time? Under this assumption are any stores offering pre-sous-vide meats?

Loic 12y ago

For the readers, this is not a "sous-vide" cooker, only a temperature controlled immersion cooker. "Sous-vide" means "in vacuum" and usually you combine low temperature controlled long time cooking with low pressure. A book from Thomas Keller about sous vide cooking: http://www.amazon.com/Under-Pressure-Cooking-Sous-Vide/dp/1579653510 http://www.amazon.com/Under-Pressure-Cooking-Sous-Vide/dp/15...