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The guy who made it so difficult to open your bag of potato chips (rheothing.com)
160 points by jmjerlecki on May 2, 2012 | hide | past | web | favorite | 91 comments

The guy we really need to find and punish is the one who invented "rigid plastic clamshells".

The kind that "conveniently" transforms from product packaging into a razor-sharp weapon while you are trying to open it.

Clamshell packaging was made for retail shelves. To prevent shrinkage and increase product visibility, it was designed to be transparent while simultaneously difficult to open.

The explosion of Amazon and other online retailers made the advantages of clamshell packaging moot. However if you are a manufacturer, it may not be economically feasible to produce two different types of packaging for different retailers so lowest common denominator wins out.

Amazon has tried to combat clamshell packaging[1] with a few manufacturers (Fisher-Price, Mattel, Microsoft), but it has yet to be adopted by the rest of the manufacturing industry.

[1]: http://bits.blogs.nytimes.com/2008/11/03/amazoncom-cuts-pack...

> while simultaneously difficult to open.

I think we can all agree that someone overshot that target by a long range. Every single time I ask myself, "now how can I open this without damaging neither the package's content nor myself in the process?"

Sharp scissors and a lot of patience. Never try to open one without them.

Of course, your scissors don't stay sharp for long because the plastic is hard enough to blunt them pretty quickly :/

Use a can opener around the sides of it. For most clam shells, the top will then just lift right off.

> To prevent shrinkage and increase product visibility,

Which is also a feature to discourage shoplifting.

note: i am an idiot and don't know what "shrinkage" means, disregard this post.

Shrinkage is shoplifting.

I believe shrinkage is most commonly used by retailers to mean theft by employees. Shoplifting is customer theft.

Shrinkage encompasses all of the above [1]. The retailer I worked at for a few years (::shudder::) used this definition.

[1] http://en.wikipedia.org/wiki/Shrinkage_(accounting)

Shrinkage is any loss of product, hence shrinkage of inventory.

(I worked at a grocery store for four years, the same company my dad has worked at since 1977)

Shrinkage = shoplifting, employee theft, damaged product, vendor fraud, price errors in favor of customers... the hard plastic shell mitigates all of these.

Out of curiosity, what did you think 'shrinkage' meant in that context?

Wow yeah I was really confused. English is my third language and I can often figure words that I don't know from the context except that in this case I interpreted 'shrinkage' as some kind of a tendency do produce smaller products (electronics get smaller for instance). And I thought ok it seems a large package makes the product more visible on the shelves. Then I thought "ok" actually a large package would be hard to sneak under one's shirt. So it would be good for that as well.

"English is my third language"

I don't think that's the problem - I had no idea what shrinkage is and:

- English is my first language

- I've worked in retail (though I rarely paid attention back then)

I read the original comment and (before scrolling down) was tempted to chime in that 'in this context, shrinkage means "theft"' before realizing the discussion had already been had.

I could very easily see someone as having read that as physically shrinking in size, perhaps due to compression by repeated handling, as would happen in a store, or heat or other uhhh... harsh environmental factors commonly found in retail establishments. (Sorry, I couldn't think of a second good excuse)

At first I thought it mean preventing packages from breaking when they are piled one on top of another for storage. To preserve fragile products inside.

why does clamshell pacaging prevent shop lifting? it's not like the packaging is tied to the shelf

But the package is quite large and rigid and thus relatively hard to conceal.

Also when stored like this: http://www.bendbulletin.com/apps/pbcsi.dll/bilde?Site=BB&...

you can put a lock on it as well.

If you're a young whippersnapper, you might not remember the horror that was the CD long box, designed to make compact discs harder to shoplift, back when people stole music that way.


I love learning about things I would never come across in everyday life, like how a packing machine works and the problems no one would ever think to think of like air pressure and altitudes. Then also the restrictions put in place and how to come up with a creative solution to a problem. This is the kind of stuff I live for.

I think my love of these kinds of videos started with this: http://www.youtube.com/watch?v=HMU-wXsgyR8

The air pressure certainly has an effect. I live in an only somewhat-high-altitude city (Calgary) and most of the chip bags you see are puffed up like balloons.

Once had a bag of chips burst while driving up into the Rockies.

Check out this playlist of manufacturing processes - pretty cool: http://www.youtube.com/playlist?list=PL3AFB507B668AF162

I think the most interesting part of this post was the comment about how they use multiple scales with chips to get closest to the desired value.

This is really a neat hack that probably allows for much less precise chip dumpers. I'm reminded of how awesome randomized algorithms in CS can seem, but in real life it is just extra magical.

True. Straightforward application of the Knapsack problem: http://en.wikipedia.org/wiki/Knapsack_problem

More a case of discrete chip mass.

You could have very accurate chip scales, load cells are cheap and very accurate - but how do you select exact 'N' grams of random sized potato chips?

Having a set of pans, where the first has eg. 17chips with a mass of 4.5g, the next has 19chips with a mass of 5.9g etc and then selecting from 4 of them them to hit the 20g bag size is very clever.

Exactly. It allows for less-precise (i.e. more variability) chip size, not chip scales. :)

Simplifying the scenario might clarify what's happening. Imagine any given chip could weigh 1-2oz. And you are trying to fill a 2oz (minimum guaranteed content) bag. You already have 1 chip in the bag, weighing 1oz. The next chip you add (think "marginal" from econ class) weighs anywhere from 1-2oz and could tip the scale all the way up to 3oz, when you are only looking for 2oz in the bag. But if you use two scales, you have now a choice of TWO chips to put in the bag, so you pick the one that weighs closest to 1oz. And ultimately this allows you to fill more 2oz bags with the same quantity of chips.

At 4:10 in this video https://www.youtube.com/watch?v=LkqBbr7Ewsw you can see a VFFS machine in action.

(I find 'how its made' to be musak for nerds but that is a different post :-)

You can link directly to 4:10 in the video.


Holy shit that's brilliant.

I admittedly haven't been to Youtube in forever, but that actually got me to click, if only to find out how (other than altering the querystring by hand) you did it.

I still didn't see how to do it though. Is that a logged-in option perhaps or am I just missing something?

When you are at the time you want, right click on the video, and copy the link with the time.

"Copy video URL at current time"

That's all there is too it :-)

Another alternative is http://youtubetime.com/

But I just modify the query string by hand. :-)

Or add &t=XmYs to the URL (where X is minutes and Y is seconds).

> "(other than altering the querystring by hand"

Parent I was replying to already knew that part...

I've been watching "How It's Made" on NetFlix, I am on Season 3 and it is awesome. Although, I do tend to get hungry for the foods they show :P

Really? That show always turns me off of eating processed foods. If I watched it every day I'd go paleo for sure.

I'm on Aderall, and by the time I watch the show its effect has worn off (watching it RIGHT before I go to sleep, the guys voice makes me go to sleep), making me slightly hungry, but not enough to get out of bed and actually make any food, besides I don't like eating right before I go to sleep.

Yes, there is a lot of food that is on there where I can find myself saying "well, definitely not eating that ever again".

I find this article to be quite frustrating. It's like reading about how some process was too slow, so they looked at the variables which include a faster processor, more RAM, and larger storage. Ultimately, they chose more RAM and developed a new algorithm and all was solved. But then they never tell you what the algorithm is. Or why it allowed them to keep within the constraints of the same processor and storage.

In this case, it's a new adhesive. But how was that developed? What makes the new adhesive better suited to high-pressure applications while keeping the temperature and time constant? Inquiring geeks want to know!

OK now let's find the guy that invented those crinkly Sun Chips bags.

agreed - and then lets ask them about the total fabrication that they are biodegradable.

Biodegradable... eventually.

edit: So I looked it up and it should only take 14 weeks in an active compost pile. I wonder if anyone has ever tested it?

Almost no change after 25 weeks in a home compost pile: http://cockeyed.com/science/compost_chips/sunchips.php

Interesting. I'm skeptical of the marketing because 14 weeks doesn't seem like long enough. I'm also skeptical of this experiment though.

Sunchips specifies 14 weeks in a hot and active compost. A new compost pile (like in the experiment) would not be very active compared to an old one, especially since he didn't add any worms to it but he did get the water and turning right. He also mentions that it was cold and rainy in the weeks after he started his compost. An old compost would shrug this off but it would have a negative effect on a newly started compost.

A friend of mine teaches gardening to children and they tried it. After 4 months the bag was a bit thinner and worn but not drastically different. They figured that in a large communal compost it might only take 14 weeks to biodegrade as communal composts are considerably hotter then anything you could have at home.

especially since he didn't add any worms to it but he did get the water and turning right

I've just started home composting (with a tumbler) and I thought that adding worms to hot compost was a bad idea, in that hot compost is too hot for worms to live.

What makes you say it's a fabrication?

they may work in a 'proper' compost, but i can testify that they do not degrade in mine

i know them. i believe a lot of the crinklyness was actually overcome by changing to a different type of heat seal, but this was after or very close to the time when the axe was dropped on the PLA bag. but there are lots of other biodegradable materials out there.

Seems like a good design would be to have seals that are extra-weak to shear forces while being strong for all the other kinds.

One type of seal I see has a nick in the side.

It's still sealed, but the nick gives you something to leverage, so you can tear the packet open. Perhaps this isn't as common in the US?

The nick you're describing creates what structural engineers call a 'stress riser' in the material of the bag. It focuses the force you exert on the bag to a small point, from which the tear will originate.

Stress risers are a common cause of structural failure, and are usually designed around. Some well known examples where they cause failures: rectangular window openings in aluminum fuselages, knots in fishing line, a poorly designed head tube lug on a steel bicycle frame.

In this case, however, the failure of the material results in a good outcome: snack time.

I see them over here all the time... you'll find them on jerky packets, for example, or as the initial seal on nearly any re-sealable bag (think of a bag of cereal with a zipper on top). The problem is that if the Seal God (blessed be his flippers) doesn't smile on you, you'll end up ripping off a sliver of the top of the bag and completely failing to get a decent opening. This has caused much wailing and gnashing of teeth. I think the material used for the bag/packaging is definitely a factor--I can pretty much always make a good tear on a ramen flavor packet, but I don't know that I've ever had a bag of jerky open properly.

God, all this talk of cereal and jerky and ramen makes it sound like I eat only crap. I eat vegetables, I swear!

It is, though it doesn't always work, and it's easy to tear a sub-optimal opening.

They frustratingly don't often work with greasy fingers. Which you might have if said sachet or packet comes with, say, a fast food meal, or from inside a bag of crisps (like Salt n Shake in the UK).

Given the shape of a bag, it seems pretty difficult to put shear force on the bag. Since the sealed layer deforms and crumples, if for example you grabbed onto both sides of the middle of the top edge and tried shearing them apart, they would just reorient so that the forces are now more or less normal to the glue...

Apply thumb and forefinger on either side of the seal. Press together and slide. Coefficient of friction between finger and seal might need to be increased somehow (perhaps by texturing the material differently at that point).

When i started skiing, I used to have bags of chips explode on me while driving from the California coast to Lake Tahoe, scared the crap out of me. I just decided to buy vacuum packed stuff up there.

"The point here is that while technical options exist to prevent premature opening of the bag, such as reducing the initial air pressure in the bag, attempting to add this to the existing processing equipment would be a nightmare. So it was necessary to increase the seal strength."

You could also reduce the air pressure in the factory, e.g. by building it in one of the aforementioned high-altitude regions.

True, however there would be a trade off with chip cooking times, no? If water boils at a much lower temperature at high altitude, then I assume oil would as well.

But then again, you could cook your chips in pressurized vessels a la Kentucky Fried Chicken. But you'd still have to truck all your potatoes up into the mountains. Decisions, decisions...

And/or heat up the air filling the bag. As air cools, the volume decreases.

The right solution would be to squeeze to depress the bag a bit as it's sealed. Increasing the seal strength is a quick and dirty hack, but as we've all learned too well from software, the right solutions often got trumped by quick and dirty hacks. The customers just have to live with the consequence.

Your ideas have other suboptimal consequences though - sucked-in bags don't look as nice on the shelf, and in fact they look smaller. This makes them less attractive and thus less likely to be purchased.

That would be even more expensive than upgrading a bunch of equipment. The whole point is that the solution had to be retrofit onto existing facilities at minimal cost.

Building an entire new set of factories in a mountain region where there are, generally speaking, fewer residents to staff your factory is a pretty expensive decision.

I'm usually pretty disappointed, because on a failed opening attempt I end up crushing those chips, and then feel like I didn't really get my money's worth.

It's alright. Chips and cereal are sold by weight, not volume. Some settling (or crushing) of contents may have occurred during shipping and extraction.

I realize they are sold by weight, but I'll be honest, the full size merchandise is worth more to me. It is even worse on cereal, my wife saves the end of the box for me because i'll eat it. I prefer the full size, but throwing out the 'fluff' (crushed bits and powder at the end) seems like a waste.

Now I know who Kettle Chips hired to make their impossible to open bags.

I was just thinking about how Kettle Chips have a small but pronounced notch that you can grab and pull. I haven't had any angst opening a bag of chips in a long time.

And here i was, cursing the idiot at kettle who thought eating chips from the side of the bag was a good idea. Opening from the top allows for easy reach and easy reseal.

eating chips from the side of the bag

After you easily open the bag of chips, you pour them into a bowl and set on the table. Do you drink wine straight from the bottle or pour it into wine glasses?

My good fellow, I'm sure that when you partake in the delicious fruit known as an apple, undoubtedly you do like I and first neatly slice and core the apple. Once the fruit is thus prepared, I find that arranging it neatly in a circular pattern on a fine porcelain plate (preferably covered with an exquisite paper doily) is a most acceptable presentation format. How uncouth are the heathens who consume the apple straight from the stem, exposing the unsightly core in plain view.

I know i don't entertain my guests like a housewife from the 50s.

Well, you're doing it wrong.

From the perspective of a right-hander: Hold the bag upright with the notch on the left, use your left hand to grasp the upper-left corner, while using your right thumb and index finger to begin tearing downward. As soon as you break into the actual cavity, begin tearing rightward.

Invert appropriately for a left-hander.

Or just do what I do and keep a pocket knife around. Shrug

This post you made is just begging you to read The Design of Everyday Things. :) I'm going through it right now, amazing book. Highly recommended.

So they replaced an easy and obvious way with one that requires careful coordination. And still ruins the bag for reseal. No thanks. Like the other guy said, "design of everyday things".

I really don't understand the objections. It's quite easy and obvious to me, has been since I was a little kid and was first confronted with sealed bags and packets like that, and I have exceedingly poor coordination.

Not to mention the Pop Chips bags...

Not so difficult if you keep one pinkie nail 3 inches long and razor-sharp (as do I).

so when trucks would drive their chips out to California, some of the seals would open up due to the pressure difference between the high altitude air and the air sealed inside the bag

This is backwards, isn't it? Less dense air from Colorado would shrink the bag in California.

I'm guessing he was saying that while the chips were in transport of the passes into California, the low pressure at the high altitudes combined with the higher pressure in the chip bags would cause the bags to break open. They'd be back at normal pressure at the destination however. I also think he meant East of the Rockies as to where they were made, considering West of the Rockies is California.

Yeah, it is. Your shampoo usually opens on the pass.

At a guess, maybe he meant the plants were east of the mountains, not west, so they would have to drive over them?

Oh, right, the mountains :)

I think it depends where in Colorado they started and where they went after. I walked and hitched my way cross country this year. I did not go through Colorado but went up and down in altitude quite a lot. I was up around 7000 feet at least three times in states I never thought of as all that mountainous. And Cali has mountains, some of them quite high.

> Other options besides a stronger seal are technically possible, but not economically feasible.

It would have cost next to nothing to attach slabs of foam rubber or gentle spring plates to the sealer. As the two sides move together, the air is gently squeezed out of the bag first. Sheer incompetence.

I'm not sure if I exactly understand your solution. Would you be lightly squishing the contents of the bag with the spring plates while sealing the front?

It also seems possible that manufacturers wouldn't want chip bags to look comparatively "deflated" when sold in a same-pressure environment (and thus stand out less on the shelf compared to competitors'). Also, maybe bags rupture for reasons other than pressure change and thus a stronger seal is still desirable. Just guesses, though I know the article didn't make mention of any of those reasons.

Wouldn't evacuating the air from the packaging make the chips inside the container crush and break easier?

It's always been my understanding that the head room inside the package helps protect the contents.

But it's not until the chips settle that this will be effective, unless you are ok with crushing chips to get the air out.

And who said they wanted to squeeze the air out --and have the deflated look, easy crushing and all?

When one talks about the "sheer incompetence" of a group of industry experts set to find a solution to a problem in an internet comment thread, while putting out an inane "solution" of his own that doesn't take all facts into account --and when he never knew all the constraints in the first place--, well, the Dunning–Kruger effect springs to mind...

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