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Just a note, the machines are not broken, they have shut themselves down for sanitary reasons. Ice cream, as a food that is very close to neutral in pH and with
by wnissen 6y ago
Just a note, the machines are not broken, they have shut themselves down for sanitary reasons. Ice cream, as a food that is very close to neutral in pH and without much in the way of preservatives, is a common source of listeria bacteria. To prevent serious health issues, the machine must be sanitized regularly. As I understand it, the process is involved, and any given McDonalds may not have a person with the time and skills to complete it. So the machine shuts itself down rather than produce an unsafe product. This is translated to "broken" when you order ice cream.
- missedthecue 6y agoHow hard is it to devise an ice cream machine with a simpler sanitation process?
- cm2012 6y agoConsidering McDonalds is on the forefront of food automation tech, probably harder than you think.
- madeofpalk 6y agoI would have imagined someone in technology (or at least enough to read HN) would understand the hidden complexities of things they're not intimately familiar with
- missedthecue 6y agoWell I don't, hence why I'm asking...
- ajford 6y agoPasteurization via heating the entire machine to a high temp and holding for some time is likely the simplest you can get. No need for cleaning solutions, flushing, etc. Simply heat the thing up for a few hours. As for duration, that's a function of temperature and desired safety margin. The higher temp you go to sanitize, the faster you can sanitize, but if they're heating the ice cream mix as well, there's likely a limit to how high they can get without damaging/altering the mix. So the other variable is time, and that's probably what leads to the multi-hour sanitize cycle.
- tschwimmer 6y agoI recently saw a video that actually showed the machine (allegedly) was sterilizing itself. The video showed all the ice cream in the hopper melted and soupy, presumably heated to kill bacteria in it. The video creator claimed it took some hours to complete, thus the common claim that the machine is "broken"
- duxup 6y agoI suppose ice cream isn't high on the list of services they feel they need up and running all the time, but if the machine is determining this I would think there would be some level of predictability that would allow them to schedule sanitizing and etc. It's funny that the machine tells them there's no ice cream. I visited my local library for a tour. They have an automated system that collects returned books, sorts them, scans and processes them, then puts them in boxes to be shipped to other libraries if they need to go there. Or puts them in carts and labels them with instructions about the efficient path to travel to return books... The humans just take orders from the machine when there is a cart ready with books to be put on the shelf or boxes to be sent to other libraries. Interesting times.
- macd 6y agoThere's a great short story called Manna that builds on this idea: https://marshallbrain.com/manna1 https://marshallbrain.com/manna1
- ada1981 6y agoThis is such a great short story!
- aeyes 6y ago> I suppose ice cream isn't high on the list of services they feel they need up and running all the time Depends on the country, here it is hot 9 months of the year. People queue up for ice cream every day. McDonald's has mini stores only selling ice cream. Maybe it's the same in hotter parts of the US (which the article is about), for example Florida.
- hug 6y agoIt's about ten years since I've worked with an ice-cream machine, but in my experience no matter the model they never forced you to try not to serve ice-cream. They would enter their self-pasteurisation cycle, and the display at the front would tell you that is what it was doing, but it wouldn't prevent you from pulling the handle, if you so wished. The problem, though, was that the barrel of the machine where the mixture was normally frozen was now at some 60 degrees C, it would be much much higher pressure than usual, and since the entire staff of a McDonald's tends to consist of teens who don't exactly take pride in the precision in which they carry out their jobs, at least once a night you'd have some poor kid blast a fine mist of hot sugary milk over themselves and the surroundings. Sometimes twice. Sometimes I miss working at McDonald's.
- userbinator 6y agoBut why "broken" instead of "down for scheduled maintenance"? The latter implies continuance of service, the former leaves that open.
- eli 6y ago"down for scheduled maintenance" is phrase that's very common in the tech world but sounds weird in a restaurant.
- InitialLastName 6y agoGiven the "entitled customer" incidents I've experienced, seen, and heard about, "scheduled maintenance" sounds intentional and like something "you shouldn't be doing when I want my ice cream", where "broken" sounds like something the guy behind the counter can't help. I'd be willing to bet that "broken" is just less likely to start a fight with an enraged customer whose day was very slightly inconvenienced by their inability to consume extra junk food.
- jl6 6y ago“Down” used in that sense is computer jargon. “Broken” is universally better understood, at the small cost of some accuracy which doesn’t matter to the customer.
- johnsillings 6y agoIt matters to me
- tenebrisalietum 6y agoWhy? What are you going to do different if you are told it is broken versus down for maintenance? You're still not getting any ice cream?
- istorical 6y ago
- seanwilson 6y ago> Ice cream, as a food that is very close to neutral in pH and without much in the way of preservatives, is a common source of listeria bacteria. How come the the high amount of sugar in ice cream doesn't help? Would it be any different if it was a non-dairy milk like soy?
- rlonstein 6y agoSugar itself is food. It's the fact that sugar draws water out of the medium that it retards some kinds of bacterial growth (not botulinum for example).
- theobeers 6y agoThat effect kicks in at higher sugar concentrations, e.g. a 2:1 sugar:water simple syrup, which can have some shelf stability. I don’t think soft-serve mix would be even close. You need for there to be little enough water in the solution that cells with permeable membranes will be desiccated through osmosis. This can be seen in a common household science experiment, where you remove the outer shell of an egg by leaving it in vinegar for a while, then submerge it in corn syrup to watch its further transformation.
- skykooler 6y agoSugar is pH-neutral, and is not itself a preservative (it's pretty much the opposite).
- joezydeco 6y agoHere's some detail, as someone that has worked with those machines before (internally and externally). In the good old days the soft serve and shake machines were taken apart every night and every piece was washed and bleach-sanitized by hand. Then it was reassembled in the morning. This would leave a lot of room for error and possible contamination in the process. And the sight of a shake machine hitting full pressure with a misaligned O-ring in the barrel is a lovely one indeed. So the newer machines take a different route: they self-pasturize. The machine goes out of service and slowly heats everything up to a bacteria-killing temperature (including the dairy mix inside), then cools everything back down to freezing temperature to serve. This process takes about four to five hours. But if you set the clock wrong, the machine will go into its cycle at some super-inconvenient time. There are other triggers that can force a self-clean but in general it's not "broken", it's just doing this process at a bad time for you. I'm curious how this data is being sourced. The last I checked there was an effort to put cloud-based telemetry into every unit and have them report home constantly (both to the equipment maker and to McD), but that was never intended to be public data. EDIT: Ah, I didn't RTFT. He's using the public ordering site to scrape it (and now the title has changed). But that does mean there's some working connection from the equipment to the McCloud now. That's cool. Or maybe a manager is doing it by hand.
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- ehsankia 6y agoAt first I was gonna ask why does this not run on off hours, but then you mention bad clock, so the next question is, why is the % of bad clock so high, and why isn't the clock also cloud based or set in a way that can go wrong. Next up, what about redundancy, do stores only have one machine?
- thisisnico 6y agoCloud based clock. Don't you mean NTP? We've had this technology for years! If it's connected to the internet, it's a pretty fundamental piece of pretty much any networked OS. You can ensure correct time this way.
- bradly 6y ago> Ice cream, as a food that is very close to neutral in pH and without much in the way of preservatives, is a common source of listeria bacteria. Former Blue Bell Creamery CEO was recently charged with seven counts of conspiracy and fraud for not taking proper actions in regards to ice cream based listeria in 2015.
- m1 6y ago> Ice cream, as a food that is very close to neutral in pH and without much in the way of preservatives, is a common source of listeria bacteria. I know very little about food science so apologies in advance but curious as why they don’t add preservatives themselves to the Ice cream and why other pH neutral foods McDonalds do don’t require as much care as the ice cream?
- technick 6y agoI can tell you from working at mcd's in the late 90's, nobody wanted to clean the machines or take care of them, so we would turn the machines off. The manager generally didn't care unless someone complained to corporate or the franchise owner.
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- 55555 6y agoOh I see so it's a feature, not a bug. :)