I don't think the lids are hard to open because they're screwed on tightly, but because there's a vacuum in the jar? (cf. those Age of Enlightenment experiments where large teams of horses couldn't open vacuum-sealed containers.. history doesn't record whether the horses ever stopped pulling in teams and tried just unscrewing them...)
Possibly you could make them easier to open despite the vacuum by making the thead pitch finer - but I suspect that since the threads are cut into glass rather than steel there's a limit to how fine-pitch they can be made and still be robust.
But anyways - why is there a vacuum in the jar? To preserve the jam? Isn't jam a preserve? Like, I thought the whole raison d'etre of jam was as a way to make fruit keep, unrefrigerated, through the winter? Why must we preserve the preserve? Quis custodiet ipsos custodes?
I'm pretty sure that when old ladies from the Women's Institute make jam to sell at the village fête [at a manufacturing cost of £2 per jar.. which they then sell at a cost of 50p a jar.. to raise money for.. old ladies..] they don't vacuum-seal the jars, and their jam seems to keep just fine.
Lastly (probably well-worn common knowledge - apologies ...
3But anyways - why is there a vacuum in the jar?
Jars are filled while the contents and the jar are boiling hot, which kills anything that might spoil it. As it cools, that creates the vacuum, which also pulls the lid tight to create a good seal. Properly jarred food, per my understanding, will be safe to eat pretty much indefinitely, but once you open the lid it will be exposed to pathogens and start spoiling. So the jam sold by old ladies should be vacuum sealed, if they did it properly.
Preserves also happen to have extra preservative properties, due to the high sugar content and acidity, which makes it last well even after opening the jar - but it will still spoil once open, especially if it's unrefrigerated.
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1As commented elsewhere, do not use a butter knife, use a teaspoon. Not sharp, stronger, dosnt slip, better shape for levering.
Ok, it seems the American butter knife is a deadly weapon. The butter knife I mean has a rounded tip usually not even a serrated edge and it's basically impossible to cut anything with it. Except butter.
I always get mad when my wife mutilates a bread roll trying to cut it with a butter knife. That's what a bread knife is for.
The reason why I prefer butter knifes is that they are much easier to get under the lid. They are only sharp enough to cut butter so you can also grab it close to the tip if you need to.
Yes, don't use anything that can stab or cut you even if for some weird reason you call that a butter knife.
My pet theory is that jars being too tight is a plot by a shadowly cabal of reactionary foodstuff manufacturers hellbent on recreating traditional gender roles. The freemasons, Don Draper, cadet branches of the house of Valois, and the Michelin man all implicated.
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2AIUI, grip strength is one of the physical attributes where there is the least overlap between men and women (even compared to other measures of upper body strength like bench press)
My goat is gotten by things like seatbelts, headrests, and gym equipment that are actively hostile to people under 5'9''.
The world is also hostile to the tall. The tyranny of the mean...
The number of times I've banged my head on an extractor fan......
IME there's at least as much skill as raw strength in opening containers. Occasionally my wife will hand me a jar to open; almost always I can't open it on a low-effort first pass either, and so I do a bunch of superstitious rituals on it that I've acquired over the years without theorizing about it, and then it will open effortlessly.
Because of the relevant cultural assumptions, she can pass it off to me, while I look incompetent if I can't open it in response, so I've had more reason to accrete all the rituals that seem to work in aggregate.
For many caps a good portion of what makes the cap difficult to open is the vacuum used to seal the cap. I'm not sure whether that's the case for Gatorade but for Raspberry Jam that's probably what's going on. You can take a spoon to pop out the vacuum.
Even through I'm a man I find it much more comfortable to just use a spoon to pop the vacuum seal than to use force with grip strength to open jars.
When searching for the video for the spoon illustration there were also plenty of other tricks to getting out the vacuum. If you do a bit of experimentation with opening technique, you should be able to find something that works for you.
2I think the main problem is getting enough grip, not rotation per se. It'd be a lot easier if jar lids had little wings like on a wingnut. No idea why something like that hasn't caught on.
Let me formulate a new question:
What is the reason for jars requiring such force?
a. Conscious engineering decision to maximize the probability of preservation with a deliberate cutoff around ~50% of the population. (E.g. when testing the engineers coming up with the design were male and created something they could still open)
b. The most economical way of producing such preserved food by chance happens to require this amount of force. We ended up doing this as about 50% of the population can still open it. In an alternative universe with weaker male hands we would not have such storage as it would be unusable.
If the answer is "a.", this should be much easier to change than in case of "b.".
Part of this is will be redundant with other comments.
If we are strictly speaking about jam jars with screw on tops (like this https://vendingsuperstore.co.uk/cdn/shop/products/111357_1.jpg) then I think the answer is "women are able to open them if they have the necessary knowledge".
There are 3 mains technics I know to help open a jar, some of them I also sometimes need to use as a man.
- Use a dry piece of cloth to turn the lid, such as a towel
- Run the jar under hot water first
- Use either the tip of a knife or the back of a spoon to let some air pass under the lid, which helps reduce the pressure difference. As other comments have noted if you use a spoon then you must use is as a lever to push the lid upward and if you use a knife you must push at an angle to turn the lid a bit as you let the air in. I think the knife method is more effective but it is a bit dangerous (you might cut yourself if careless) and it can damage the knife.
I am french and in my entire adult life I don't think I ever saw anyone fail to use one of these technics when necessary or need to give up on opening a jar. I just asked my girlfriend and she confirmed that she never has issues opening a jar on her own. The vibe I get from this post and some of these comments is "the knowledge of jar opening is not being properly transmitted in some places". Perhaps there should be a disclaimer on the jar?
I will add a fourth technique, which is the one my wife uses:
4. Whack the upper corner of the lid with a knife or spoon until it is dented in several places around the circle. This breaks the seal and makes it easier to open the lid.
1I am a woman. I know/ use all the techniques people are listing.
I still have troubles opening lids.
(Also it's annoying a bunch of guys being like "don't you know to run hot water?" etc, as if we didn't)
I know this is not the main point of the post, but have you played around with one of these?
I got one about a year ago and found it fun for a few weeks and worth the price. I think most people can significantly increase their practical grip strength in a few weeks of playing around with it
If a jar of food loses its seal before sale, it's garbage. Jars have requirements about maintaining a vacuum and not getting opened accidentally, and a design that's easy for women to open seems to be more expensive overall than women getting a jar opener, which you can find on Amazon for like $7.
The Danish marmelade brand Den Gamle Fabrik has this thing they call the "swup-låg", which is super easy to open! I do expect that they're more expensive though (they consist of two parts)..
Here is a cute promotional video^^ https://youtube.com/watch?v=NbPMjWsPOsw
It is actually possible to design lids that are easier to open. See for example here: https://metalpackagingemea.sonoco.com/our-orbit-closure/
I already tried a jar that had one of those lids linked above. It was indeed a lot easier to open.
The way that it works is that the lid consists of two parts. The flat upper part presses against the sealant surface and doesn't turn. The ring shaped part on the side that grips into the threads of the jar does turn. The fact that you only have to overcome the friction in the threads and at the point where the two parts...
The amount of force required to open containers feels like it varies based on type of food contained within while seeming relatively consistent within food categories (jam jar lids are, generally, harder to open than peanut butter jar lids; peanut butter jar lids seem harder to open than that of animal cracker jars).
Are there any sanitary benefits toward a tighter seal that constrain certain food categories and not others in this way? Or is it just something along the lines of genre convention: 'Well, jam jars have historically felt this way, and we don't ...
This seems like a totally reasonable complaint to me. I wouldn't even call it petty. Everyday things should work for everyday people.
My personal experience of life is that 70% of jam jars opened by myself and the women around me pass unremarkably without comment, and then another 10% even the guys can’t open without tools. Would be curious to get some empirical measurements on the actual variation in resistance between jars, even of the same brand. Could be extremely spiky!
But also I’d gladly pay an extra buck for jam to avoid needing to strategize how to open the damn thing 30% of the time!
The design is part of the vast conspiracy to keep women smarter and more coordinated than men. Putting lots of little challenges in their way gives them lots of reasons to think critically and problem-solve, swap solutions, and emotionally bond.
I keep raising this issue at Patriarchy Club meetings but the guys are just too dumb to listen and insist on keeping the jars this way just for their amusement. They don't see that they're being had by the Matriarchy Club. They just call me a conspiracy theorist.
Friction materials make jars vastly easier to open. Si...
1In addition to the raw force thing, estrogen alters the structure of skin and makes it less friction-y compared to testosterone based skin.
I agree with the other commenters that tightly sealed jars are good. Just use a stray butter knife. Mind over matter.
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1Interesting perspective. If I were asked about the difference between the grip strength in men and women, a priori I would have guessed the overlap between the strongest non-athlete women and the weakest non-athlete men was bigger, so this is a bit of a surprise. Though to be fair, I've been lifting for several years and live in a very gym/sports-forward social bubble, so I'm generally biased towards overestimating the average cis woman's strength.
Another sorta related thought: While it seems that women ask for help opening jars more often than men, my int...
Trans women on feminizing HRT often report losing the ability to open jars irrespective of diminution of strength. One common report is that this is correlated with changes in skin texture.
Edit: I see that datawitch has already brought this up. Pardon the redundancy.
I wonder why we continue to purchase the specific products which don't meet our preferences for opening them. Probably something complicated and sociological about tolerating inconvenience, or something?
But if the goal is to easily open the maximum possible amount of jars, including out-of-distribution jars that even people with male grip strength struggle with, there's a tool called a strap wrench. They're available for cheap in the plumbing section of your local Harbor Freight or any other hardware store. I keep 2 in the kitchen and have never met a scre...
A sturdy wooden stick about a centimetre across can be hard to break for most women and easy to break for most men, without any of this being the doing of a patriarchal society. With traditional jars, the kind you can also make at home, the resistance to opening comes from the basic sterilisation process, which creates a partial vacuum inside. Larger jars, like those of cassoulet (to stay in southwestern France, as with Bonne Maman), are often impossible to open even for a man and generally require the help of a piece of cutlery. If they aren't hard to ope...
1I'm a man with genetically (probably!) slim wrists and forearms. I say genetically, because my younger brother is one cut away from six packs and focuses on his forearms in particular, and he still has forearms that are only respectable and not impressive for his reference class. There have been somewhere between 10-20 times in my life that I've been unable to open a jar or container, and had to ask another, beefier man to do the honors (while swallowing the dishonor).
Like you, I have been slightly aggrieved about it. Oh well, all I can really say is that ...
Installing an under-counter jar opener was a win for our household.
It's so grippy that it gouges the lid sometimes, so I use it for disposable lids like tomato sauce but less for things like "a mason jar I intend to use again, which my husband has screwed on way tighter than I can unscrew."
I'm a man with amateur-athletic grip strength, like I dead lift and rock climb, and I can't open many jars unassisted. Note the trope of a man opening a pickle jar for a woman often involves the man handing it to a second man, who opens it, then the first man says "I loosened it for you."
Jelly jars, and those small jars of ginger paste require breaking the air seal by banging it with an implement. Probably there's a better way, I learned banging.
I can think of some containers designed to require an implement - wine bottles, paint cans, beer bottles.
It seem...
It seems an unfortunate consequence of the forces involved in making vaccum sealed preserves. If the force necessary to open the jars were higher than the average male grip strength, then I predict we would have jar-opener devices as standard in kitchens, like we have can-openers or bottle openers. In fact, the old style cork screw for opening cork bottles is probably requiring the higher side of male strength, which explains why we have the newstyle bottle openers with the cog wheels and arms as a force multiplier.
In short, blame the patriarchy for normalising a lack of jar-openers in kitchens, but don't blame it for the force required to open a jar.
Just curious, as many comment seem to be focused on vacuum being the source the force required to open, is this about first time you open a jar or that or times where someone else has closed the jar and you then want it open?
Quick additional question, but data might be scarce, have you considered looking at the grip profiles for left and right handed people for open the standard jar? Hand position is different and I'm honestly unsure if the structure of the wrist is such that twist strength is symmetric.
I have this gadget and it works great. I think there are other screw-top-openers with different characteristics, but I can't attest to those.
It's sort of amusing seeing all the comments from men saying "actually all the difficulty is in the vacuum, and you just have to release the vacuum and then it's easy" -- no! you don't understand! It's easy for you once the vacuum is released, but there exist lots of people for whom even un-vacuumed jars are often difficult to open! It's not just an issue of there being some inherent difficulty in opening vacuum-seale...
As a man, I find it difficult to be consciously sympathetic of the strength difference. The force that I use to turn the faucet knob to a comfortable, definitely closed position actually requires an uncomfortable amount of force to open for my grandma. Would be interesting if someone made bottles and knobs that are 2x harder to open than usual...
Sometimes even I can't open a jar. I use a C-Clamp to deform the cap by screwing into the cap diameter, and pop the air runs in and pressure lets go.
I hear you when you say you want to be able to open jars without tools. And you're right, it is likely because women weren't considered during the design process. The force due to pressure is a manufacturing requirement. But the friction under pressure is not. If a lubricant was added to the jar rim or lid before the lid was put on, both genders would enjoy opening jars without using tools. The increased manufacturing cost would be marginal. The temporary unique selling point of "Easy open" would pay back the early adopters quickly. By the time it was standard and those USP profits dwindled, it would not make financial sense to be the only jar you can't open easily.
Most of the proposed fixes in this comment thread accrue a privatized cost, available only to those who can pay it in money, infrastructure, or skill. A $10 gripper, running hot water requires electricity and water paid by the user, retained knowledge and space to store a gripper. It’s infuriating when you get a drink from a gas station on the go and you can’t open it.
This post shows a known concept of an implicit gendered tax. It can also be shown with office hvac systems being designed for male metabolic rates…making women supply an extra sweater or spac...
I mean for jar-opening, how easily you can open a jar would also depend on the sizes of the hands, not just the grip strength.
i heard from someone a while back that it wasn't actually about grip strength it was that women's skin is softer and less able to handle the friction. wait i'm wrong
Wow, that chart was enlightening. I would definitely have assumed that this was at least in part driven by males refusing to admit they can't open something and therefore being more willing to go to extreme lengths risking personal injury, or resorting to different tricks. Which in hindsight translates to "women don't try as hard" which I'm not proud of!
OK, so can we fix this? In my experience the jars I (a male) have been asked to open are typically wide mouth glass jars with metal twist on lids. As others have noted a lot of the struggle with the ini...
Worth noting, perhaps, is that the main reason people fail to open jars is not due to a lack of grip strength, but due to a lack of friction. If you have a stubborn jar that you cannot open, put on a pair of rubber dish gloves and try again, and I think you'll be surprised at how easily a previously-unopenable jar magically pops open. This method has literally never failed me.
Methodology: Methodological holism is required here. The inability of women to open jars is not explained by any individual woman's grip strength or any individual jar manufacturer's torque specification. It is a structural property of the capitalist packaging system, in which engineers optimized for shelf-life and shipping integrity, generating a civilization-wide distributed imposition (T1-4 Against Rent-Seeking and Capture, T3A-6 Against Systematic Engineering of Exploitable Vulnerability) on everyone whose hands are smaller than the industrial design a...
Maybe this is insensitive but have you considered getting stronger? I have no idea how much you work out or how much your housemates worked out, but ranting about the tyranny of grip strength seems like it won't work as well as increasing your grip strength. Since you said that you're sure you're low in female grip strength distribution, getting stronger would actually be pretty easy
Huh, when I was a child and did not have male adult levels of strength yet, I always jammed a kitchen knife in the cap and wiggled it until I did something that let air in. That usually solved it.
Easiest trick I've learned is just to run it under some warm water for 30 seconds (sometimes more but often enough) and then it just slips right open without a struggle. Had problems with a weirdly tight ketchup bottle the other day (the brand has never caused me issues before or since) and it went from literally impossible to easier than lifting the bottle itself.
I don’t imagine Bonne Maman wants to stop women getting to their jam—I imagine that nobody cares.
Nobody is allowed to care. The notion that the average female is in any way inferior to the average male is one of the strongest taboos of "polite society".
Just use a teaspoon to leaver it open, no issue. They are a much better lid opener than a knife, stronger and not sharp.
I'm pretty annoyed today, for nominal reasons ranging between ‘petty’ and ‘doesn’t even make sense’. I’m not entirely sure how or if to take oneself seriously when one has such absurd grievances. But that’s a question for another time—I’m here now to tell you about my one potentially valid peeve.
I understand that gender is complicated and difficult, for the whole species (and honestly probably more so for some other species). And it can be hard to tell exactly if anyone is behaving badly regarding it, at least in my modern bubble. Maybe women just aren’t that into designing programming languages? Maybe the thing I’m saying is just boring and a man is saying a more interesting thing?
But a thing that is undeniable is that women want to open jars, dammit! What’s your nuanced explanation there, Bonne Maman? Does the proper amount of friction for maintaining spread safety fall just between the male and female human grip strength distributions?
This study suggests that would be about 400N Fmax (though this would not avert most elite female athletes acquiring jam, see second figure, and the pictured participants are young adults):
The distributions are really surprisingly not-overlapping!
90% of females produced less force than 95% of males. Though female athletes were significantly stronger (444 N) than their untrained female counterparts, this value corresponded to only the 25th percentile of the male subjects.
We know that men and women have different grip strengths! We know that about half of people are women! Why do so many containers require women asking a man for help in order to open them? (Or carrying around an opening tool or living in a kitchen?)
Yes, strength required to open packaging ranges across a wide distribution, but I note that very few are impossible for anyone to open, so it seems like some effort somewhere goes into keeping them in the feasible range, and that effort does not seem to care about it being reliably feasible for people like me. I don’t imagine Bonne Maman wants to stop women getting to their jam—I imagine that nobody cares.
I thought about this most when I lived in a group house with a shared bulk stash of Gatorade, and any time my woman housemate or I wanted to drink a red one we’d have to ask a guy to open it for us. But these days I also often hurt my hands opening (or failing to open) things, and while I’m sure I’m low in the female grip strength distribution—and may also be high on the ‘unreasonable anger about anything nearby when my hands are hurt’ distribution—I don’t think it’s just a me issue, and in the moment it always feels like a ‘fuck you, raspberry jam isn’t meant for you’.