I’m thinking of like when you bottle wine that’s still fermenting, and it explodes. I understand that the fermentation process raises the air pressure inside the bottle. What I *don’t* understand is how? When you pump air into a balloon, the air pressure rises because there are *more* air molecules entering the balloon.
With wine in a bottle, you have a fixed amount of matter at a certain temperature. I don’t understand how fermentation could increase air pressure in a closed system?
In: Physics
Fermentation happens when yeast eats sugar. Just like in a person, digestion produces energy for the organism and waste. Alcohol and gas are produced as a waste byproduct of the yeast digesting the sugar. Without going into too much chemistry, the alcohol molecules are smaller and less complex than the sugar ones they’re made from. So the extra parts of the sugar molecule that don’t get used to make alcohol molecules turn into gas molecules. So there’s still the same amount of matter in there, it just changes form. As fermentation progresses, the yeast eats the sugar, uses the energy to reproduce, and poops out alcohol and gas. Over time there’s less sugar because it gets eaten, but more yeast, because it reproduces, more alcohol, and more gas. Eventually 1 of 3 things happens.
1) the yeast eats all the sugar so fermentation stops and the yeast dies.
2) the yeast produces too much alcohol and it can no longer survive in the alcohol rich environment and it dies.
3) the yeast eats sugar until the gas creates pressure too strong for the container and it breaks.
4) possible outcome is that the pressure gets too high for the yeast to survive before the container breaks, but that’s pure speculation. I have no idea how yeast reacts to pressure.
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