Why cans of soup are shaped the way they are

http://www.datagenetics.com/blog/august12014/index.html

by squeakynick • 12 years ago

190 103 12 years ago

stansmith• 12 years ago

Thanks, I also liked reading the last article about ice cream.

Your articles remind me how much calculus/math I have forgotten since leaving school and, sadly, how little use there is everyday to use calculus :(

egypturnash• 12 years ago

I feel like there are other efficiencies not considered in the article. Namely spoilage and portion size. I mean, you're not usually gonna need a bunch of tuna at once, so you don't want to have a huge can full of enough tuna for twenty people - but you also need it to be in a can big enough to manipulate. Also one with a big enough visible label space to actually put something legible on it.

wging• 12 years ago

Also, what about ease of retrieval? If the can's cylindrical, instead of cuboid, it's easier to retrieve every bit of a thick soup that doesn't drop out of the can.

mhb• 12 years ago

Maybe that's why spoons have evolved with curved sides instead of right angles.

grdvnl• 12 years ago

The h/r ratio does take care of portion size, though again portion size may directly impact spoilage parameters.

e12e3• 12 years ago

You only need enough tuna for one tiger.

(couldn't resist ;)

arethuza• 12 years ago

On a related point - I just finished reading "Atomic Accidents: A History of Nuclear Meltdowns and Disasters" and the author specifically mentions how the "can of soup" shape is pretty dreadful for holding fissile materials:

http://www.amazon.com/Atomic-Accidents-Meltdowns-Disasters-M...

curiousgeorgio4• 12 years ago

If we wanted to use a shape that packed perfectly efficiently, we’d use some kind of cuboid... But we don’t see many cubes on shelves. Let's look at cylinders now...

The only real reason the article gives against using cuboids is that "the edges would be stress points", but it goes on to imply that this is mostly solved with "filleted (rounded) edges to reduce stress concentrations and to make them easier to manufacture."

I enjoyed the rest of the article relating to the optimal dimensions of the cylinder, but I still don't really understand why more products don't use cuboids (with or without filleted edges). Surely the space savings for shipping and shelving would be pretty significant, no?

smackfu• 12 years ago

For shelves, maybe the packing density of randomly oriented cuboids isn't any better than cans.

(There's a practical use of math for you.)

curiousgeorgio4• 12 years ago

Who says they'd be randomly oriented? When I see examples of cuboid products on shelves (think boxes), they're usually stacked quite neatly and efficiently.

VLM• 12 years ago

Random orientation is the key, "pretty good kinda aligned face out" is very fast and cheap both WRT labor and capital, and label alignment on the can is not a cost at all.

On cuboids the label alignment is beyond critical (even just randomly off center 1/4 inch on the shelf would look awful) and the capital cost to align the cubioids perfectly in their box and on the shelf are expensive.

(edited to add, I'm not saying our economic system would collapse if the cost of cuboid soup cans went up three cents a piece, but it would be an incredibly difficult corporate sell to convince one mfgr of many that he should accept a 1/3 of a million dollar loss compared to his round competitors on ten million units sold just to make them cube-ish, for, uh, fun)

Also wear in the box. Cuboids would tend to wear off entire faces of the label while being tossed around the warehouse but cylinders at worst will end up with a vertical streak.

Finally having worked retail as a starving student a quarter century ago there is a huge installed base of semi-standardized grocery store shelving that was never designed for the peculiar spacing cubiods would require. Or rephrased, cylindrical cans and rectangular prism boxes have evolved over decades to fit certain semi-standard discrete shelf configurations... If you want it on an American supermarket shelf, then a grid pattern of X by Y (preferably one shipping crate) will take up a certain discrete space. Not a quarter inch too big necessitating reconfiguration of the whole section, etc.

Someone• 12 years ago

Not quite what you ask for, but it may interest some: http://en.m.wikipedia.org/wiki/Percolation_threshold#Thresho...

MichaelDickens• 12 years ago

Maybe because cuboids are harder to open with a can opener? All the cuboid cans I've seen have tabs on top and thus don't require can openers. It's conceivable that tab-opened cans are more expensive, don't preserve food as well, or something like that.

curiousgeorgio4• 12 years ago

You mean our tools that are designed specifically for cylindrical cans wouldn't work as well for cuboids? :)

I agree, but if cuboids were the norm, I'm sure we'd come up with a better tool for them.

Expense may very well be a factor, but if that's the case, I'd expect an article like this to mention it.

jnevill• 12 years ago

The trade off, besides the stress points, is that a can opener would not be as efficient. That is mentioned when the author moves on to the cylinder. Furthermore, not mentioned in the article, a cylinder will support much more weight than a cuboid, making a cuboid more susceptible to smashing under load.

bcohen5055• 12 years ago

While in school I spent 7 months in a co-op for a company that manufactured steel food cans. Although at the time I never challenged the need for circular cans I can say that manufacturing would be much more challenged for cube cans.

Metal likes to be formed by rolling, and it's relatively easy to image how cans are cut to length, passed through a die and seam welded. Obviously that's a lot of capital for one can size so round dies are easily swapped for various size cans on the same line. Forming stamped and bent edges would be much more intensive for changeovers.

Lids would require directional placement: Round shapes fit in all directions, pretty clear here that any other shape would require it to be directionally correct.

Can liners are sprayed: The inside of your cans are coated to protect the food, corners are harder to maintain an even sprayed coating

There are plenty of others I'm sure and this is a rambling post but maybe it gives a little more insight into the world of cans.

curiousgeorgio4• 12 years ago

It sounds like a lot of this just comes down to the fact that our processes used for producing cylindrical cans aren't optimized for cuboids, and I won't argue with that.

However, part of me thinks that given some time and ingenuity, we'd come up with techniques that are better suited for the efficient production of cuboids. In other words, most of the things you mention are conceivably solvable by the right tooling (i.e. fixed costs). If that were the case, I'd have a hard time believing that marginal/per-unit costs would be significantly higher, and I think it would be interesting to look at the savings in shelf and transportation space compared to any of those increased production costs.

nobodysfool• 12 years ago

Can liners aren't protecting the food, they are protecting the can from acidic foods.

GFischer2• 12 years ago

Well, Tetra Pak's Tetra Brik is used A LOT, and it's definitely a cuboid.

I'm not sure if it's used more or less than cylinders, but I see more cuboids than cylinders on my local shelves.

http://en.wikipedia.org/wiki/Tetra_Pak

http://en.wikipedia.org/wiki/Tetra_Brik

Edit: an interesting link to irregular can sizes (also plenty of cuboids)

http://www.sommecan.com/nonround/irregularcanguide.html

dekhn2• 12 years ago

BTW, tetra paks are non-recyclable.

lmm• 12 years ago

I think there are a few things that come in more-or-less cuboidal cans. Spam?

dheera2• 12 years ago

We do see cuboids sometimes. http://www.prevention.com/sites/default/files/imagecache/sli...

jpindar• 12 years ago

That looks like a box, not a can.

bronson• 12 years ago

Just a pic of a Tetra Pak for anyone who doesn't click the link.

e12e3• 12 years ago

And rectangular box:

http://rolande.files.wordpress.com/2005/01/spam-can.jpg

dragonwriter3• 12 years ago

I enjoyed the rest of the article relating to the optimal dimensions of the cylinder, but I still don't really understand why more products don't use cuboids (with or without filleted edges).

Plenty do, when they are small enough that they can have sufficient strength and still have a pull-top opening (lots of sardine/anchovy cans are this way.) When they are bigger, they don't, because can openers.

Though I'm starting to see more "canned" vegetables/etc. that use lined cardboard cuboids rather than metal cans, so there's that.

anigbrowl• 12 years ago

It's not all about space saving. You can get soup in cuboid packs, but I don't think it keeps as well, plus it's only good for smooth-textured soups that you can pour. If you have any kind of chunky or textured soup (which lots of people like), then opening it means unfolding/cutting the whole top of the container, which has a higher risk of spillage and requires more hand strength (for a kitchen scissors vs. a can opener). You do see it more commonly for things like chicken stock or other 'base' ingredients for cooking at scale.

Space saving matters a lot during shipping, on shelves not so much. The first job I ever had was stacking shelves in a supermarket as a teenager and I was so bored I would pass the time by calculating the volumes that fit on palette, on display and so on :) 25 years later not much has changed - most supermarkets still stack products 2 high and 2 deep or 1 high and 3 deep (depending on how stackable the product is), not least to limit the potential for mess. Smaller volumes usually have higher margins, so what's economically efficient for the supermarket isn't necessarily what's efficient in terms of volume.

mnl• 12 years ago

Maybe because cylindrical tin cans actually save tin.

Optimal cylindrical can (h=2R): V=2piR^3, S=6piR^2

Cube with the same volume: V=x^3->x=((2pi)^(1/3))R, hence S=6x^2=6((2pi)^(2/3))*R^2

That's ~8.4% more sheet metal. If you don't mind contents swirling inside the can cylinders are the way to go.

e12e3• 12 years ago

It's a shame spheres are so hard to do, it'd be even better :-)

peterwwillis• 12 years ago

Cans of soup are definitely not spherical for space-efficiency. They're spherical because from the assembly line to shipping to the customer, they simply work better. They handle dents well, they roll along assembly lines fluidly, they keep the orientation of the product labels, they're easy to inspect for quality, and they pack and unpack well. Obviously they also stay put on a shelf...

In terms of dimensions there's several factors to consider: label size, stacking efficiency and directional integrity. If you want a nice big color photo of your product, a taller, slimmer container will allow for a large color background and plenty of text for both the front and rear labels. Depending on if it's skinny or wide will determine how other products can be stacked around or on top/below it. And some foods (like tuna) keep their shape/consistency better when laid horizontally to prevent from breaking up while being transported. Similar foods hold together better when the pieces are larger, so larger portions of canned fish have the typical vertical orientation. And of course there's only so much horizontal space that can be allocated per unit before the shelves burst at the seams.

For sealable cuboid containers, more and more containers are being modified with grippable edges to make it easier to handle, since the customer doesn't use the entirety of the product at once (http://ecx.images-amazon.com/images/I/81W3JCB8tHL._SL1500_.j...). Resealable bagged containers are also becoming more popular, as they reduce the amount of air in the container, pack more efficiently, save weight, and are easier recycled. (http://www.gofoodindustry.com/uploads/members/comp-1509/file...)

jessaustin• 12 years ago

   s/spherical/cylindrical/g

001sky• 12 years ago

Yes, the article is interesting but not convincing.

The shape is a compromise for volumetric efficiency, stackability, ease of manufacture, and field-toughness.

Spheres are highly impractical on all dimensions.

Caulk and pepesi (pardon my pun) don't come in spheres, squares, or rectangles either...probably for similar reasons.

ArkyBeagle• 12 years ago

The C beverage does come in Christmas tree ornament shaped containers once a year or so. Not quite a sphere.

danielweber• 12 years ago

My first day of calculus in high school, Mr Haskell told us that in a few months we would be able to prove the ideal size for a soup can. And we did!

ethomson• 12 years ago

The "So why not for everyone?" section is interesting, but misses the reason the tuna can is actually the worst shape on the list: it's optimized for surface area of the top and bottom of the can! Tuna is actually cooked in the can (retort cooking) and the high surface area is beneficial to this process.

Maybe not the most useful thing I learned in Calc 1, but the thing I remember best.

raverbashing• 12 years ago

Exactly

Also, you won't be able to use a can opener if the diameter is too small, since can openers work in a straight line, if the diameter is too small it won't fit in the curvature

ufmace• 12 years ago

That's what I figured. Consider that the volume of a tuna can is probably limited to roughly 1 meal worth. If you made it with optimal dimensions, based on material usage, then the diameter might be too small for a normal can opener, and it might be too narrow to get all of the tuna out easily.

bsilvereagle• 12 years ago

There are lots of other really good articles on that blog: http://www.datagenetics.com/blog.html

rwmj• 12 years ago

How about the cost of the food? Tuna is expensive, condensed milk is cheap. That matters relative to the cost of the can because it's more important to make the condensed milk can cheap to store a cheap ingredient, than to worry about the minor cost of aluminium compared to expensive ingredients like tuna.

treerock• 12 years ago

Tuna £0.67/kg [1] Condensed Milk £2.67/kg [2]

Not that it negates your point. Just struck me as interesting that tinned tuna would be seen as expensive in some places in the world. I guess it depends on the quality of the tuna[3].

[1] http://www.tesco.com/groceries/product/details/?id=256557156 [2] http://www.tesco.com/groceries/product/details /?id=265540922 [3] http://www.independent.co.uk/news/uk/home-news/tesco-accused...

kbart• 12 years ago

That's £0.67 per 100 gr., so it's actually £6.7/kg -- 2.5 times of condensed milk.

unreal37• 12 years ago

The article fails to mention the main reason food is shaped "inefficiently": serving size.

Besides being cooked in the can (as egypturnash points out), a can of tuna contains two sandwiches of tuna. A jar of tomato sauce contains two servings of tomato sauce. A can of soup contains two servings of soup.

Yes, you have to be able to hold it in your hand, and stack it on a shelf. But you can't make a smaller can because that would be "less soup". No one wants to buy smaller cans of soup, and the manufacturers certainly don't want to sell less soup per purchase either.

Economics trumps material efficiency.

selectodude• 12 years ago

A can of tuna is enough tuna for two sandwiches? Yikes, I must be getting big.

blt• 12 years ago

It's not! unreal37 must be a little kid :)

giarc2• 12 years ago

But a can with optimal shape could be produced that contains the same volume of tuna. I think "tradition" is the factor here. Everyone knows that a can of tuna is like a hockey puck shape. If you all of a sudden changed it to a different shape, I'm sure people wouldn't even recognize it.

GFischer2• 12 years ago

Most cans of tuna here (Uruguay) are not hockey-puck shaped - and soup doesn't come in cans either, but in Tetra-Paks, except for the rare Campbell's import.

Searching for images I came across this very relevant article on irregular can types:

http://www.sommecan.com/nonround/irregularcanguide.html

Example of tuna cans in some spanish-speaking countries:

http://www.conservera.es/images/stories/virtuemart/product/3...

vsbuffalo• 12 years ago

Great post, but "data genetics"? It would be nice if they didn't misuse the word genetics — this site has nothing to do with genetics.

squeakynick3• 12 years ago

Thanks, but it's just a name. Just like you are not really a buffalo :)

Joking aside. DataGenetics is the consultancy company I set up when I was doing that line of work. It was all about spotting trends/patterns/explanations in data (sort of like the DNA), and the term described the work I did. A lot of the work I did was related to video games, and what the characteristics (chromosomes) were about games and how they performed. When selecting a business name, you can chose to attempt to describe your business function in the name "GreatPokerHands", "DataGenetics", "CheapTickets" or you can try an obscure reference "Amazon", "King", "Zynga" and then spend additional money educating people on that brand and what it represents. (Amazon sell things online, and has nothing to do with the river. If we listen to Jeff, he says the name was selected because it started with the letter "A", so will appear first on lists).

I continue to blog under DataGenetics as I own the domain, and have followers there. It's a hobby. Not every post is about data, either, it's just a place I put my thoughts. It's my hobby.

http://datagenetics.com/blog/may52014/index.html

serf• 12 years ago

While I ultimately understand your point, I don't believe the name explains your business in the least bit, I believe you found a middle road which is neither self-descriptive or abstract in the way the name 'Zynga' is.

The name you chose is not obscure or esoteric, but rather uses two words associated to information and relies on the reader to make the connection that your business has something to do with information. The problem, however, is that 'Genetics' refers to a specific domain of information -- this leads the reader to believe that the 'Data' (an ambiguous term for unordered knowledge) refers to datums regarding 'Genetics' (the specific form of data which biology/inheritance are so concerned).

The first thing that popped into my mind when reading the name was "Must be a biotech/bioinformatics group.".

I don't want to sound critical; i'm not trying to. I've been linked a few articles on that blog and enjoy the content -- just trying to give you some (probably) useless data on how John Q. Public may encounter the site.

jscheel4• 12 years ago

My grandpa designed the bottom of modern beverage cans. The reason for that shape is two-fold. First, the bulge is for pressure resistance. Second, the rest of the design was created specifically for the optimal application of the epoxy spray that prevents your drink from developing a metallic taste. Unfortunately, he didn't patent his work and Anheuser Busch ultimately took his idea for themselves. Never prevented them from being his client though, for other seamless can tooling work.

lifeisstillgood• 12 years ago

If your grandfather is still with us, please can you persuade him to share his story with the world "the man who designed the beer can" has got to be one of my must reads :-)

Edit: of course if he no longer is, my condolences, but please tell us what you can remember.

squeakynick3• 12 years ago

TeMPOraL3• 12 years ago

Seconded; please share the story, or if your grandfather feels like it, maybe do an AMA on Reddit. That will be one hell of an amazing read! :).

jscheel4• 12 years ago

I'm in the process of recording my grandpa talking about his life. He actually doesn't say much about the bottom of the can. Basically that he went back to his shop and sketched out some ideas based on the technical specs he knew they needed, and just kept building prototypes until it worked. I'm going to try and get him to tell me more about it this weekend. Here's a short recording of him talking about a fix he did for the military: https://soundcloud.com/jscheel/frank-scheel-ammunition-work

squeakynick3• 12 years ago

Awesome!

8_hours_ago• 12 years ago

As someone who has on multiple occasions left a case of beer in a car during a Montana winter, I thank your grandfather for making the cans bulge but not explode when frozen :)

Theodores• 12 years ago

It is a pity that your grandpa didn't write this article. No offence to the author however there is no substitute for industry experience.

My father sold tooling for making cans and there were many small but important innovations that came along. It wasn't as if someone sat down and designed the finished thing, innovations came along and the likes of your grandpa and my father made things happen. Sometimes it would be a slither of steel that would be saved per can, other times it would be innovations that would go nowhere - anyone remember transparent pet-plastic cans? No...!

In introducing a change, an incremental change there is no way that the whole production line is going to be upgraded/altered, as in everything else connected to a conveyor belt.

The modern ring-pull tops were obviously a huge part of this story of innovation, as was being able to extrude the base and sides of a can out of a disk. However, the real innovation behind these processes is to have some type of press and tooling that can make these wonderful and intricate shapes in as few steps as possible. That is when you have a business case, and that technology - real technology - is a long way from the 'easy' stuff presented in this article.

Related to alcohol beverages is the story of the Guinness widget:

http://en.wikipedia.org/wiki/Widget_(beer)

The Wikipedia article just explains a little bit, however the small bit of plastic in beer cans took decades to get right and the investment level was considerable, even for a brewer the size of Guinness. Combined with the technology that goes into the can, a beer can is quite a technical wonder.

jscheel4• 12 years ago

Hehe, he was also part of the group that worked on the extrusion process for Reynolds. He owned a company in Minnesota and there were hired to come in and work on it with them. He's got a lot of great process stories like this. I've actually been recording him talking about his life recently. Here's a passage about a tooling innovation he came up with for the Twin Cities Arsenal during the Vietnam War: https://soundcloud.com/jscheel/frank-scheel-ammunition-work

alister2• 12 years ago

Does anyone remember when beverage cans used to be so thick that it was considered an exercise of manliness to be able to crush a can--particularly a beer can--with one hand?

I had always wondered what the key innovation was that allowed aluminum cans to be made so thin. Based on a TV episode of "How It's Made", I think the key idea was to develop machinery that could delicately stretch and extrude aluminum without tearing it.[1][2][3]

Amusingly, there seems to be 3 versions of the same video with different voices saying the same words:

[1] http://www.youtube.com/watch?v=L4EzU8792e0 Original female Canadian narrator

[2] http://www.youtube.com/watch?v=V7Y0zAzoggY Male American narrator

[3] http://www.youtube.com/watch?v=V4TVDSWuR5E Male British narrator

guard-of-terra• 12 years ago

Koreans still make cans that thick. Every time I buy korean soft drink I'm amazed by its can toughness.

alister2• 12 years ago

The bottom of a modern beverage can has a glowing blue ring that you can see only under UV light (aka black light). I've seen this on Coke, Sprite, and other soft drink cans.

The bottoms of the cans are coated with a varnish to make them slide easily on conveyor belts and in vending machines. It's the varnish that glows.

hackuser2• 12 years ago

The purpose of a food can is to store food.

Absolutely not. The purpose is to maximize profit.

The can improves profit via sales (being appealing on the shelf and in the kitchen cabinet; perhaps a familiar shape sells better), marketing (the image of the brand and the product, including environmental issues), distribution (the obvious costs and the value of being appealing to the sales channel (e.g., oversized products might be unappealing to the supermarket)), manufacturing costs, functionality for the consumer (food stays fresh, fits standard can-openers, etc.) etc etc.

moheeb• 12 years ago

I am not attempting to "maximize profit" when I purchase cans of food.

hackuser2• 12 years ago

I am not attempting to "maximize profit" when I purchase cans of food.

You aren't designing the cans.

victorquinn• 12 years ago

No mention of can openers, and how they work their way around the cylindrically shaped can?

Think of how a can opener would work with a cube, hexagonal, or other shaped can.

Cool article, but seems it builds a lot of assumptions into its analysis.

johngalt2• 12 years ago

Squarish cans are used today for some items (sardine cans come to mind). They usually open with a tab or key along a seam. A hexagonal or octagonal shape could use a tab with seam approach. Like a large soda can.

Luyt• 12 years ago

The article asserts:

"Aesthetically, a slightly taller can looks nicer. The Golden ratio is approx 1.6, so a can with a height of approx 1.6x it's diameter (3.2x the radius) would be very appealing."

However, it is a myth that the Golden Ratio is the most appealing ratio. Many things, from the Parthenon to paper sizes, don't have a golden ratio and that doesn't make them less attractive[1].

Also, the supermarket in my neighbourhood sells soup in a variety of containers (cans, tetrabriks, plastic bags) and if only the standard soup can would sell well, I wouldn't see the other packages.

[1] http://skeptoid.com/episodes/4325

"Perhaps the best known pseudoscientific claim about the golden ratio is that the Greek Parthenon, the famous columned temple atop the Acropolis in Athens, is designed around this ratio. Many are the amateurs who have superimposed golden rectangles all over images of the Parthenon, claiming to have found a match. But if you've ever studied such images, you've seen that it never quite fits, at least not any better than any other rectangle you might try. That's because there's no credible historical or documentary evidence that the Parthenon's designers, who worked more than a century before Euclid was even born, ever used the golden ratio in any way, or even knew of its existence."

autokad• 12 years ago

i think most importantly, its stating that the golden ratio is appealing, which is somewhat unquestionable. that contrasts with what you said it said, which is that its the MOST appealing ratio. obviously there are many considerations that go into a soup cans dimensions, the author was only offering a LIST of other possible reasons other than volume/surface area efficiencies.

2ndly, theres a difference between not having golden ratios and not being based off the golden ratios.

tripzilch• 12 years ago

There really is nothing particularly more appealing about the ratio 1:1.618.. (the golden ratio) than there is about ratios of 1:1.5, 1:1.666.. or even 1:1.333.., for that matter.

It has a bunch of interesting properties, but aesthetics is not one of them.

lnanek2• 12 years ago

We do have a lot of cubes. Juice boxes. Cereal boxes. Wine boxes. Cylinders are pretty much only used when you need to fake larger capacity for consumer preference (cardboard nut containers in super markets vs. plastic cubes of them at Costco) or you need to use metal for some reason (e.g. tanks of pressurized gas, holding liquids with the top off, etc.). I think he kind of misses the point that cubes are superior in terms of space usage then goes and analyzes how space efficient something we are only forced to use for other reasons is.

bdamm2• 12 years ago

I was dismayed to find that they did not dive into the ribbed shapes as well.

qntmfred• 12 years ago

they need to start optimizing the shape of nacho cheese jars so that i stop getting rim cheese all over my knuckles every time i dip a chip

bnolsen• 12 years ago

The M&M shape is the most efficient for minimizing empty space in shipping containers. They missed that one.

coryking• 12 years ago

Cans of soup could also be shaped the way they are due to the fact that it might be easier to pasteurize a cylindrical can than a cube. The heat can be more evenly applied to a cylinder than a cube.

fencepost• 12 years ago

This leaves out or glosses over some very important areas, namely the use to which the can is being put. Soup cans are taller than ideal for minimum material use in part because it's easier to pour from them, while on the other hand a tall skinny tuna can would be hated. For a more extreme example, consider the guava paste can - an inch high and 6-7 inches across because of how the product inside is used. Think about trying to pour your soup out of that.

lafar6502• 12 years ago

I think the authors overlooked the most obvious reason for cans being cylindrical: a cylinder is very resistant to vertical compression, so you can stack cans very high on pallets without worrying about bottom layer deformation.

Why cans of soup are shaped the way they are

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