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A solution to The Onion problem of J. Kenji Lopez-Alt (2021)
- deleted 2y ago[deleted]
- jfengel 2y agoNot "The Onion". The original capitalization is "the Onion Problem", i.e. the problem of dicing onions into even pieces.
- kunwon1 2y agoI was confused, especially considering this [1] is still very recent [1] https://theonion.com/kenji-lopez-alt-returns-from-beef-dimension-with-new-sear-method-beyond-human-comprehension/ https://theonion.com/kenji-lopez-alt-returns-from-beef-dimen...
- dole 2y agoI also thought I had my finger on the pulse of some The Onion/Lopez-Alt beef, like TMZ on the Food Network. ontopic edit: I am interested in an optimal onion cutting technique, while I'm happy with mine, the upside-down banana teaches that there's always a few ways to approach and learn something.
- jghn 2y agoThis is exactly what I thought of when I saw the headline!
- deleted 2y ago[deleted]
- JimmyWilliams1 2y ago[flagged]
- perihelions 2y agoPlease don't LLM spam on here.
- ackbar03 2y agoYou want even cuts you throw it into a blender
- greenpresident 2y agoThat’s the engineering solution. You could also hire two interns to do it layer by layer, call it the consultant‘s solution.
- octocop 2y agoThen it seems you need consultants to get a guide Michelin star
- selimthegrim 2y agoThat sounds like a cost plus defense contract if there ever was one
- 1propionyl 2y agoIf you want an extremely fine and even brunoise that's exactly what you do.
- Maken 2y agoThe consultant solution would be to buy precut onions, so cutting perfect slices becomes someone else's problem.
- karaterobot 2y agoBesides a dice that's as even as possible, the other requirement this solution attempts to satisfy is using the minimum number of cuts. A blender doesn't satisfy that, as it's making hundreds of cuts. Then, when you present your solution to the client, you find out there was a third, unspoken requirement: that it should involve as little cleanup as possible, which the blender also doesn't satisfy. The user researcher was on vacation, and you didn't find out about this before beginning design. Damn! The blender solution turns out to be overoptimized on a single requirement at the expense of the others.
- yunwal 2y ago> First, we model the onion as half of a disc of radius one, with its center at the origin and existing entirely in the first two quadrants in a rectangular (Cartesian) coordinate system. Can someone explain to me why a half sphere (the shape of half an onion) can be modeled as a half-disk in this problem? Why would we expect the solutions to be the same? If you think about the outermost cross-sections at the ends of the onion (closest to the heel and tip of the knife), as you get closer and closer to the ends, you approach cutting these cross-sections more vertically. I'd expect that you'd have to make the center cross-section a bit shallower to "make up" for the fact that the outsides are being cut vertically. Idk, either way I think declaring this the true "Onion constant" is probably wrong.
- Cerium 2y agoI share simular concern, but also think of an onion more as a bulging cylinder due to center weighted thickness variation in layers. Each layer extends from root to stalk.
- dole 2y agoEven though onions aren't perfectly symmetrical, they still optimally grow or radiate out from one axis/line through the middle. Stick a toothpick through a sphere as this line, and slice the sphere through perpendicular to the axis, you'll get circles from a sphere, or half-disks from a half onion if you keep slicing perpendicular. I'm lazy and cut my onions perpendicularly through halves, and don't try a radial cut for uniformity.
- yunwal 2y ago> Even though onions aren't perfectly symmetrical The question I have is not about modeling an imperfect object as a perfect abstraction, it's about modeling a 3D object as a 2d object, and assuming that the optimization still holds. I think it's pretty plainly clear that it doesn't. Think about some cross-section of the onion that's closer to you and smaller than the center cross-section. Let's say it's of radius 0.25 instead of 1. The slices you take of it will be much more vertical than the center slice. This changes things. My intuition tells me it means the optimal solution is shallower than the solution found here, since you'd want the "average" cross-section to follow this constant.
- deleted 2y ago[deleted]
- OJFord 2y agoIs the problem explained in text anywhere? (TFA delegates to a video and afaict only discusses another video-suggested solution and a novel solution in text, I don't understand what we're solving.)
- ruds 2y agoYou would like to slice (half) an onion in a way that minimizes the variance in volume of the pieces. The problem is then simplified to slicing half an onion in a way that minimizes the variance in cross-sectional area of the pieces at the widest part of the onion.
- ska 2y agoThe problem is how to get roughly equal sized pieces from cutting an onion. If you cut towards the center the inner pieces are much smaller than the outer.
- sampo 2y ago> Is the problem explained in text anywhere? Not very well. There are some snippets: "to keep the pieces as similar as possible" "The Jacobian r dr dθ gives a measure of how big the infinitely small pieces are relative to each other" "The variance is a good measure of the uniformity of the pieces."
- ipsento606 2y ago> Is the problem explained in text anywhere the problem is that you want to cut up an onion in such a way as to minimize variation in the size and shape of the cut-up pieces usually, so that the pieces will cook evenly
- dylan604 2y agomeh, the food processor usually handles that for me pretty damn well
- marssaxman 2y agoYou are clearly not the target audience.
- CarVac 2y agoI'm surprised Kenji still does the horizontal cut at all. With the angled vertical cuts I find the horizontal cut entirely unnecessary. (Also a few years back I gave myself a nice flap avulsion doing the horizontal cut in an onion...)
- ImPostingOnHN 2y agoInvest in cut-resistant gloves. The few dollars will pay for themselves in non-lost time, plus you can use them on a mandolin. NB: maybe stick a hotdog in one of the fingers to test it first.
- CarVac 2y agoI have them now, but's simpler to just avoid that one dangerous and unnecessary cut that proceeds towards my body instead. They taught that in Scouting, never cut towards yourself.
- Kototama 2y agoYou need to cut in the direction of your body in some cases (for example when carving wood). Two things to prevent injuries: a) never put any force if the material resists b) do it slowly.
- bloopernova 2y agoAnd either learn to sharpen your knives yourself, or take them to a sharpening service. Dull knives require more force, and slip/catch more, so are more dangerous.
- therealdrag0 2y agoOft repeated, but I don’t think I’ve ever seen this actually studied in practice. And personally I suspect it’s more a clever meme by knife sellers.
- 2y ago
- ortusdux 2y agoOn the other hand, fellow food youtuber Adam Ragusea swears by the importance of heterogeneity. Optimizing for uniformity might not be the best strategy! https://www.youtube.com/watch?v=5cWRCldqrxM https://www.youtube.com/watch?v=5cWRCldqrxM
- jfactorial 2y agoWell the logic presented in that video certainly cannot be argued against.
- andrewmcwatters 2y agoI remember reading about the consistency of cuts from classically trained chefs. I think Adam Ragusea has a lot of niche, quirky practices that don't align with actual profession. He's more of a culinary advocate in the same way that Bill Nye is a science advocate. They're not professional chefs or scientists.
- deleted 2y ago[deleted]
- Eavolution 2y agoAdam's never claimed to be a chef or want to do things like a chef would, he tends to focus on how someone at home could do it, where things like preparing 50 onions as quickly as possible don't matter as much, hence the difference in style. I think both practices have their place, adam just home as he's never been trained in food and so all his cooking is for the home
- stickfigure 2y agoI literally came in here just to make this comment. Like Ragusea, I prefer every bite to be slightly novel and different. One of my favorite hacks for Ceasar Salad: Take a bag of packaged croutons, put it flat on the table, and crush it with the bottom of a pan. Repeatedly. Until you get a mix of various sized crouton chunks, gravel, and dust. Apply to salad. I ate a Ceasar this way in some fancy restaurant and I've been making it that way ever since.
- dessimus 2y ago>To get the most even cuts of an onion by making radial cuts, one should aim towards a point 55.73066% the radius of the onion below the center. This is close, but different from, the 61.803% claimed in the Youtube video at the top. Wife walks into kitchen with 3447 cut onions in piles: "What are you doing?!" This guy: "I just cannot get these onions cut to a point 55.73066% below the origin! The best I have achieved is only 2 significant digits of accuracy." Wife, mumbling: "Maybe that's why Kenji said: 60%..."
- deleted 2y ago[deleted]
- wcfrobert 2y agoMathematicians are wired differently than engineers. To us engineers, e is approximately pi is approximately 3.
- momoschili 2y agothink you got it the wrong way bud
- phist_mcgee 2y agoYou musn't be an engineer
- drspoulsen 2y agoHi everyone, the author of the blog here. I'm glad to see the interest here on this piece! I have slides that detail the problem setup and the mathematics, as well as a consideration of three-dimensional onions, here: https://drspoulsen.github.io/Onion_Marp/index.html https://drspoulsen.github.io/Onion_Marp/index.html I have submitted a formal write-up of the details of the problem and the solution to a recreational mathematics journal. I'm also happy to answer any questions about this!
- therealfiona 2y agoThe thing I love about Hacker News is that someone can post an article like this, then the author of the paper shows up to answer any questions. Keep being awesome.
- Eddy_Viscosity2 2y agoYou should send a "continue and persist" letter. From a HN post a few days ago: https://continueandpersist.org/ https://continueandpersist.org/
- timClicks 2y agoI love how deeply nerd-sniped you have been by this topic. It's wonderful to be able to observe your delight in solving this. Thank you for sharing.
- andrewmcwatters 2y agoI feel like mathematics and many other rigorous field-friends have tons of great questions like this that are ripe for fun research. Thanks for publishing this and contributing to that world of curiosity!
- dawnofdusk 2y agoWould be really interesting if you could reverse engineer the model which yields 1/phi as the correct answer. Evidently for some non-uniform measure on the onion you could do it. What about for considering the onion as a half-ball? (Although if you're cooking it really is primarily the thickness that matters.)
- balls187 2y agoOff topic, but the incorrect capitalization of the article misleads one to believe this is related to “The Onion” rather than “an onion.”
- mehlmao 2y agoI saw the headline and assumed it was going to be about the Beef Dimension: https://theonion.com/kenji-lopez-alt-returns-from-beef-dimension-with-new-sear-method-beyond-human-comprehension/ https://theonion.com/kenji-lopez-alt-returns-from-beef-dimen...
- deleted 2y ago[deleted]
- me_again 2y agoMarco Pierre-White recommends grating onions, which ingeniously avoids the entire issue. Grating the Gordian knot, if you will. https://youtu.be/glIUUrh6qtQ?t=40 https://youtu.be/glIUUrh6qtQ?t=40
- tdeck 2y agoAt that point why not just grind them in a food processor?
- account42 2y agoThat's going to end up with a slush of onion fibre + onion juices. Very much different from even small bits of cut onion. Some recipes call for blended onions though.
- mi_lk 2y agoSome food processors with the right setting give you chopped food not blended
- bigstrat2003 2y agoA good food processor will cut the material, not blend it.
- tptacek 2y agoHe grates for a tomato sauce, which makes sense, but you wouldn't want that as your default onion cut.
- tptacek 2y agoIn fancy cooking there's also a notion of a "perfect dice", meant literally to be that --- you pull the layers of the whole onion apart and cut/press them into sheets, so you have a rectangle to work with, and then dice that on a grid.
- ktallett 2y agohttps://www.youtube.com/watch?v=UBj9H6z6Uxw https://www.youtube.com/watch?v=UBj9H6z6Uxw
- tptacek 2y agoOne thing you see in that video is how you're not going to get anything like that out of a food processor. Does it matter? I can't remember cooking anything where it would have (though: I do want uniform dice for tacos).
- Anon4Now 2y agoI prefer the Chef Jean-Pierre method [1] because he keeps it simple. He also shows why the horizontal cut really doesn't make much sense. [1] https://www.youtube.com/watch?v=QjZ1LFqNWRM&list=PLnujfCpADfgepMC4L4foc3ejkMIZNdw4C&index=1&t=3239s https://www.youtube.com/watch?v=QjZ1LFqNWRM&list=PLnujfCpADf...
- ghc 2y agoYes! I've been using his method for 15 years with no regrets. I'm amazed to see he's still making videos after all this time.
- Anon4Now 2y agoHe had to close down his cooking school during Covid, so he started making YT videos. I watch a number of chefs on YT, and he's easily my favorite. He's a wonderful teacher, and I've learned more from him than any other because he always reinforces concepts without being repetitive and dull. It also helps that his meals are practical for home cooks, and, overall, he's just a charming guy.
- klysm 2y agoAmazing, and I was soooo glad to see the integral has a closed form. I’m very curious what this looks like in the discrete case. I’d imagine it’s somewhat straightforward to code a simulation?