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The ingenious design of the aluminum beverage can (2015) [video] (youtube.com)
126 points by mhb on Feb 3, 2023 | hide | past | favorite | 75 comments


It's interesting this would pop up, because I was just thinking yesterday about how the holes of cans used to be a different shape. I believe it was mid to late 90's. They switched over to a larger hole.

I was telling my mom and she was telling me that it didn't happen. I was hoping they were going to cover this in the video but no such luck. This did actually happen, right?


I have a memory of this, too. I remember the first soda I encountered with the larger opening being Surge.

All the other sodas I saw at the time had this opening: https://upload.wikimedia.org/wikipedia/commons/0/08/POE_Stay...

Then, not long after Surge, I started seeing the larger opening on everything.


Just for reference, it's called the 'wide mouth'. Here's the section of the Wikipedia article that references it: https://en.wikipedia.org/wiki/Drink_can?useskin=vector#Wide_...

Interestingly, I would have said that narrow mouth cans were available well into the 2000s in Australia. I distinctly remember seeing the first wide mouth cans replacing them. It's possible that because I remember them being introduced that they feel much newer than they are, though.


Yes at least in Germany you used to open cans by a lever and pull a small opening open by ripping a piece of the lid away. That usually left quite sharp edges, which I guess is why they changed the design.

You can see some of the old openings in this video: https://www.youtube.com/watch?v=MaH6q7cZv8Y

Edit correct video link


Same in UK. But I suspect they changed the design primarily to eliminate the litter caused by discarding the ring-pull piece?


Litter. And pull tab litter ending up slicing peoples' feet open. And idiots opening their beveragem dropping the pull tab inside, drinking it and slicing up their throat. No, they don't go all the way down, but they'll play hell with the soft tissue in the back of your mouth.


"Nurishment" cans, often found in the foreign foods aisle, still use the old style ring pull.

I'd guess it's because they are intended to be drunk like a soda can, but packaged in a tinned-sweetcorn style can. Those cans are unpressurized, use steel, and have significantly thicker walls (= more material cost)

I do wonder why they never decided to switch over? Perhaps they consider it part of the brand? Perhaps they still run the same canning factory for decades and without expanding sales don't see a need to retool? Perhaps the 2 pence per 1.50 product are insignificant when they have quite a market niche.


I remember grownups telling me how terrible the change was, because any dust on the tab now flipped downward and fell into the can, whereas before it was pulled away.

I was never that concerned myself.


as a kid, we'd break the tab from the pull ring and then insert the fat end of the tab into the slot on the pull ring. we'd pull the ring back on the pull tab and release the ring flying. if we were really bored, we might actually go find the ring and do it again. i was surprised at how far these could fly like this.


Same in the US. Called "pop tops" so if you were ever wondering what Jimmy Buffet cut his heal on in Margaritaville, now you know.


Same in the USA. I still find those old cans when hiking.


Don't think that video is correct


What's not correct about it?


Do you mean relevant?


I'm so confused. GP was talking about old pull tabs, and showed them in a video. You said "I don't think that video is correct."

The video does inded show old pull tabs. What's not "correct" about it?


He edited it. It was a random video before. Thought you were arguing about that incorrect video and saying I should've used the word relevant vs wrong. It's fixed now.


I remember commercials about the new bigger mouth. One where someone was choking on food and the it was like, "don't you sometimes wish you had a bigger mouth?".

Some quick googling found an old beer commercial [1]

[1]: https://www.youtube.com/watch?v=PHXNtb27IY8


Yes it happened around the mid 90s, I remember the change. Look up vintage cans of soda on ebay and such: https://www.ebay.com/sch/i.html?_nkw=vintage+soda+aluminum+c...


I used to work for Alcoa, the main driving company behind aluminum adoption across many industries. They made the sheet metal for aluminum cans, and purchased canned water to serve to guests (rather than buying plastic bottled water). Prior to wine, about the only time you'd encounter an uncarbonated beverage in an aluminum can was if your city lost water and the beer manufacturers would send a semi worth of canned water in for emergency relief. Uncarbonated beverages don't make the same sound when opened, and there's definitely a mental hurdle I had to get past because it seemed like it should be carbonated when an aluminum can is at your lips.


Fun fact: Bill introduced me to bourbon (while our spouses attended UIUC together) and so meticulously explained what “neat” means as a drink order, that it’s my preferred drink to this day (~ a decade later).


Doesn't "neat" just mean without ice?


Yeah I'm not sure how meticulously one can possibly describe "put the bourbon in a glass."


I'm not quite following, I don't see a video related to whiskey on the profile of the video posted to this thread?


I think GP was referring to an IRL meeting.


It's just an anecdote about the guy.


I like this guy. I think the best videos he made where the ones on Faraday's Candle lectures.

https://www.youtube.com/watch?v=RrHnLXMTOWM&list=PL0INsTTU1k...


It’s a shame he doesn’t post videos anymore, his students are lucky to have him as a professor.


Anyone noticed that cans have gotten thinner in the last 10 years? Seems like they actually made the process even better. Well, for them, not for me. I've had more punctured cans in the last 2 years than in the 10 years before that.


Definitely different per manufacturer here in Europe. Coke cans have always been thicker than Red Bull for example, like I think in general our 0.25l cans. But yeah, the 0.33l cans have become thinner over the last 20 years, but I can't say if progressively or at some point from A to B. I don't buy cans a lot, but I don't even remember if I ever had a punctured one except when maybe dropping it on concrete...


I put one (0.33L, btw) in a bag today and it punctured. I was really surprised as I really didn't think it had been under much if any stress.


They are susceptible primarily to corners, and after that, to edges. The sharper, the worse.

The way they are made, and the type of aluminium they are made out of, results in them failing after experiencing comparatively little strain (for being a ductile metal alloy). Because the walls are so thin, squeezing them with the grip of a hand won't cause much strain, due to the large bending radii (seen relative to the wall thickness). But if you concentrate the force around a (comparatively to your fingers) sharp corner/edge, especially if it's a corner sharp enough to hurt if you pressed on it with your hand and, say, ~5kg worth of force, you'll force it to stretch to conform to the pointy corner's shape. (Despite the factory already pushing the material close to it's limit as far as stretching-before-ripping goes. No wonder it rips, then.)


Tangential: In the early 2000s, WD40 dramatically changed their can design in an effort to thwart product counterfeiters. I remember at the time reading that WD40 was the single most counterfeited product in the world.

https://www.packworld.com/design/materials-containers/news/1...


> The dome-bottom uses less material than if the bottom were flat.

How does a dome-bottom, which has considerably more surface area than a flat-bottom. result in less material used?

> A typical aluminum can today contains about 70% recyclable material.

Only 70%!? So out of a half trillion aluminum cans per year, effectively 150B are not recyclable. What is the non-recyclable material, and what happens to it?


A flat bottom would require a thicker layer of aluminium to provide the same structural properties.


Of course. Thank you.


The other commenter pointing out that not all cans are recycled is part of it, but the other part is that many metals can't be reused as-is and maintain alloy correctly. For instance, if you want to cast aluminum, you don't want melted down cans because those are intended to be stamped and are made from an alloy optimized for that. You would be better off to use some melted down cast aluminum so that it has the right additives for casting, but there are still subtleties in the broader category relating to casting pressure/temperature/etc. So, you might not want 100% recycled material, but rather 70% recycled and purified and then 30% of the right things to get the alloy you want with the properties you want. So, it's probably <100% and >70% of cans getting recycled combined with you want to only use so much recycled material for this application and the rest gets recycled somewhere else.


Cans can only be recycled if they end up in a recycling centre. Cans sent to landfill are functionally non-recyclable, at least for the foreseeable future.


I saw somebody dissolved a soda can in acid, it remained in a plastic bag (which is probably plastic lining inside). But %70 rate seem so low, how does glass fare?


In the Netherlands 80% of all glass is recycled [1] (it is 100% recyclable as long as you don't care about the colour). In the UK the percentage is a bit lower, 67 % for green glass, 48 % for brown glass and 43 % for white glass [2].

[1] https://recyclingnederland.nl/soort/glasrecycling/

[1] https://www.gov.uk/government/statistics/uk-waste-data/uk-st...


Glass has really low rates in the US, 31%. https://tablascreek.typepad.com/tablas/2022/07/why-is-glass-...


In Germany the glass recycling rate is above 80% depending on the year. However this also depends on the source of the glass. According to the German federal Environment Agency only 7% of glass built into cars was recycled, while on the other hand 84,1% of glass sourced from packaging was recycled.

link to the information from the German federal Environment Agency (in German): https://www.umweltbundesamt.de/daten/ressourcen-abfall/verwe...


Interesting that this is popping up. I just read about wine in cans. And when I go to a beer festival now, there are many expensive rare brews presented in cans. 3-5 years ago cans were the poor mans packaging. It's amazing how large a role marketing/blogging plays in the perception of something like packaging techniques.


Possible that an opaque can appeals to more people than seeing the hops fluffing around the bottom of a bottle.

(Although there is plenty of Weizen in bottles around where sediments are on show)


Crowlers became a big deal with microbrewers, you could sample the beer at their location, and a Crowler was a lower barrier to entry then buying a glass growler, then remember to have it with you the next time.


I couldn't figure out from the video at what stage and how is the liquid and the carbonation placed inside. I assume it must be just before putting the lid on, but I don't see how the lid is put on if the contents are generating outward pressure.


Carbonation is an odd process... You can carbonate a liquid (by bubbling CO2 through it at high pressures). That liquid, if put in a cup, will slowly lose its carbonation, over a few hours.

If you put a sealed lid on the cup, the pressure will build up inside the cup as some CO2 comes out of the liquid into the top of the cup, till there is an equilibrium and no more gas comes out.

Thats what the canning process relies on. So the can isn't sealed under pressure - the can is sealed at room pressure, and then within a few minutes the pressure builds up inside the can.

Kinda neat!


That makes sense as to why two liters go flat faster. The more you drink, the more space in the bottle. The more space, the more CO2 that would be allowed to escape the liquid.


The top sits on the rim of the can then the edge is rolled closed like a tin can. Sealing takes a fraction of a second. There isn't really time for pressure to build under the lid before it is sealed.


They run through a seamer right after the filler. I work in the industry. It's a neat process. The can exits the filler, a lid releases and is seamed just after.


Presumably that means if the machine is stopped for a few minutes for maintenance, and then resumed, you need to watch out for a handful of cans where the pressure will have escaped.


Is it really wise to waste that much metal on beverage cans?


Not only is the planet Earth made of 1.59% aluminum, aluminum recycling is so incredibly efficient that a full 75% of all aluminum ever produced in history is still in active use in a recycled form.

If anything, we should probably be using more of it for everyday products like food containers, as a safer and more eco-friendly alternative to the sheer amount of plastic found in the supermarket.


I don't believe it is so straight forward. Aluminium smeltering is an extremely CO2 intensive process (essentially you need a lot of natural gas to generate the heat, I think there are experiments with hydrogen but they are nowhere ready yet). Moreover in contrast to glass recycling where you can reuse the bottle (common in many areas), that's not possible with aluminium. The big advantage is weight, so a comparison between glass and aluminium typically depends a lot on transportation distances and how complex recycling processes are.


Aluminium melts at temperatures that, as far as ovens are concerned, can be classified as "tame". Sure, the oven needs to be built heat-resistant, but a melting point of just 660C allows things like uncooled structural steel to be used. This is so tame, that the molten salt type nuclear reactors (well, some of them) are able to serve as a heat source for such an aluminium recycling oven. 10 years ago there were coal power plants in active development that used high-pressure (around 350 atmospheres; 75% higher than what consumer-grade pressure washers tend to max out at) supercritical (700C) water to drive the first stage of their turbines, in an effort to extract more of the coal's chemical energy through exploiting a greater temperature drop. The aluminium oven does not need to handle such severe pressures, or contact with fast-flowing liquid that is as corrosive as water at those conditions (they can use a gas between the heat source and the aluminium, and fire brick style material between the aluminium and the structural walls of the molten-aluminium-bucket).


I think Iceland has a big (big for Iceland, at least) aluminium smelting industry. They don't have the ore, but plenty of cheap hydro and geothermal energy.


The heat is typically electric (which may or may not be CO2 intensive).

The reaction does produce CO2.


Totally agree aluminum is well recycled and glass hits even higher percentages outside the USA.


Aluminum cans have a plastic lining.


But all of that plastic is incinerated and even otherwise hopefully less prone to micro plastic production, so not a real issue?


IFF recycled.


Beverages with carbonation go flat and stale rather quickly in plastic containers. For soda this is tolerable, perhaps because they have alot of carbonation and can lose quite alot. But for beer it sucks. Some regions around the world use plastic bottles for beer to keep costs down, but the already cheap beer is even worse than it might otherwise be.

Glass works well but I believe the costs, accounting for aspects like shipping weight, are greater.


There are more sturdy multi-use plastic bottles that may be as good at keeping the pressure as aluminium cans. But not as good as glass bottles.


So the best option is to drink bottled beer from a regional brewery, to keep the shipping costs down.


I'm not an expert, but apparently transport accounts for only 11% of carbon emissions for food [1], and I suppose it's likely similar for beer. To me this suggests factors affecting production are far more important.

[1] https://news.climate.columbia.edu/2012/09/04/how-green-is-lo...


Best option is to get a refillable growler from your local brewery. Or, get beer from the tap at your local pub.


Growlers go flat too quickly. I typically don't want to consume a half gallon of beer in one sitting.


Apparently there are growler tap kits, so that the growler can be enjoyed throughout the week instead of a single sitting.


Deposit return systems work but it's really annoying now that I have a big recycling bin, I still have to pay 10 cents a can and then feed them into the machine one by one, the machines are always full or broken and they're usually only open until 7pm. So then I end up with hundreds of cans since I go to the store later, and they cap the amount you're allowed to return at one time.


The German deposit system for single-use beverage containers seems to not suffer this badly from "always full/broken, limited opening hours" machines. If the machine is full, it will usually be emptied soon, and I can't even remember if I've ever caught the only machine at a location being broken. I have vague memories of something like that, but 1) it's been about 10 years, and 2) I'm not even sure if it was broken or just whining about it's crushed-beverage-container-bin being full.

According to [0], the true chains (i.e., not just franchise brands) of grocery stores, at least the nation-wide relevant/big ones, all don't have a limit on how many containers you are allowed to deposit per visit (the machine will eventually fill up and if it's the only one they have, you'll have to wait until an employee has a chance to swap the bin out).

Unless they have it in a separate niche with it's own entry door separate from the rest of the store, the machines seem to be active/ready until they deactivate the motion sensors on the exterior doors, which happens around 20:55 and 21:00 around here (most of the stores nominally close at 21:00, but some few stores stay open between 1 and 3 hours longer).

[0]: https://www.t-online.de/heim-garten/haushaltstipps/id_923339...


Same here in Norway. It's rare to encounter an out of order reverse vending machine and all but the very smallest supermarkets have them and most such places are open from 07:00 to 23:00. Never encountered any kind of limit on how many and now that all the cans and bottles are crushed in the machine it's quite rare for the bin to fill up too.


The law in Michigan (and I think New York and other states are similar) is retailers must allow returns of up to 250 containers, but can choose to accept no more than that. I think the reason is to prevent people from buying uncrushed scrap cans from neighboring states without a deposit system, and returning them in a state that does have one.

The other big annoyance in Michigan is retailers only have to accept returns for the drinks they sell. So you have to keep track of what store a container came from, because if only that one store sells it, only that one store will accept its return.

A lot of times if the machine doesn't take a few of the containers, I will just give up and throw them away, because the stores don't provide recycling bins which is even more frustrating. Or, people will just leave the cans they couldn't return on top of the machines in case anyone else wants to try tracking down where they can return it.

Also, the law says any retailer must accept returns, but in reality only supermarkets with the money for the machines do. Smaller stores like gas stations generally don't.


Oh, we bundle the deposit to the can, and trying to trick the machine into accepting something that doesn't actually have the deposit on it would be fraud (you'd get caught if you'd do it at a scale where it'd be worth the effort, so it doesn't really happen).

I think small vendors may get away with only accepting what they sell, but supermarkets here have to accept the _types_ of deposit-laden containers they sell. So if they sell Monster Energy cans they also have to accept Rockstar Energy cans, and I'm pretty sure also all the other normal aluminium beverage cans.

For reusable bottles it's a bigger effect regarding the "only the types of containers they sell", as a shop without any glass bottles wouldn't have the infrastructure to handle more than individual quantities of reusable glass beer bottles (mostly the matching crates).


It's not wasted. It's 100% recyclable. Well nearly, the resin or plastic layer on the inside and he ink on the outside are not.


mmm spraypainted epoxy laquer


Well, I'm thirsty.




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