How does the button on my pickle jar pop once opened for the first time?

Question

I have this button on a few jars around the house like jam jars, they are always glass. Why does the “button” pop once and never again?

In: Physics

Answer 1

I dont know the specifics. But i believe that when they are putting the lids on the product, they seal the jars under pressure. So when you open it for the first time, they release the pressure and the lid is popped.