system
Given the following post, respond as if you're commenting on Reddit:
human
What is happening when a chip goes stale?
gpt
Mostly it is just atmospheric humidity entering the food, making it lose it's crunch. The water activity in a crisp chip is very low, so left exposed to the environment, it will come in contact with water in the air and lose it at a much lower, not even comparable rate. Theoretically this would happen until equilibrium is reached. The starches will then soften when exposed to water, making the chip more chewy. The opposite effect is seen in very turgid fruits and vegetables. Because their water activity is so high, they slowly lose water to the atmosphere. The equilibrium is in the opposite direction, although in this case, the water is actually helping the plant cells to stay "crisp" because of the water pressure against the cell walls. As water slowly escapes, they lose pressure and become limp. To test this out, you can leave a cucumber in a very humid, sealed container with some wet paper towels and compare it to a cucumber left on the counter for two days to see the difference. Also, you can try to re-crisp your chips and crackers by throwing them in the oven for a few minutes.