Why are pickle jars so hard to open?

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Why are pickle jars so hard to open?

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The pickle jars are pretty much sealed tightly to ensure no bacteria can get into the jars. In addition, the way they are packaged also results in jars to have a vacuum seal. That’s why there’s a pop the first time you open it.

On the assumption that you mean shelf-stable pickles, not refridgerated ones, it’s because they need a tight seal. This is nothing unique to pickles but pickles tend to have larger lids than a lot of other jars so you notice it more.

When they process the pickles to kill everything inside the jar so it won’t spoil (the entire reason you don’t have to refridgerate them) it creates a vacuum between the top of the liquid and the lid. That pulls the lid down onto the jar really tightly, and there’s a thin layer of rubbery stuff on the bottom of the lid that rests on the top of the jar. The combination of pressure on the lid, pressure from the lid threads, and the rubbery layer gives you a nice tight seal, and hence tasty pickles “forever”. Except when you first go to open it you need to fight that pressure and thread tension and the “stickiness” of the compressed rubbery layer. The bigger the lid, the more force this takes. Once you break the initial seal it’s usually just fine because you never recreate the vacuum.

They have a pretty strong vacuum inside, which helps with shelf life. Due to the low pressure in the jar, the atmosphere puts quite significant pressure on the lid, pushing it *hard* against the jar. This creates a lot of friction, and you also have to *lift* the lid against this force. Until you’ve lifted it so much that air gets in and equalizes the pressure.

When you seal pickle jars, you close the lid and heat it up. The air inside expands and leaves through any small cracks between the lid and the jar. Then, when you cool it all down, the air inside shrinks again, but there is less of it, so there is a lower pressure. This causes a lot of friction between the lid and the jar when you try to open it.