The difference between fermenting and rotting?

Have you ever opened a bottle of milk and smelt it wondering it is rotten? Have you ever wondered why blue cheese is edible? Why is yoghurt safe to eat but after a little longer it is dangerous?

The answer is the difference between fermentation and rotting. The end result.

While uncomfortably philosophical the difference between rotting and fermentation is whether the outcome is what you want. If something rots it might still be useful. If it ferments it might not be what you want. It is the juncture of both intention and outcome that differentiates rotting and fermenting.

Take the example of cheese. Cheese by its very nature is a product with bacteria present. They add flavour, texture and aroma. Of course you also want to stop the bacteria from doing so at a certain point. If you don;t the taste, texture and aroma may go too far. That is too far even by the standard of some very egregious and offensive ‘cheese’.

You can think of the extreme cheese as fermenting too much. This is the grey area that eventually becomes rotting. That is when the fermentation not just runs too long but much too long leading to unwanted outcomes.

You might think that si obvious as an example. The question then would be what else could happen.

Thinking of cheese again we can see what happens if you try and cheese but fail. Instead of fermenting into cheese curds you get milk based alcohol. This is a fermentation but is not what you want. Sure milk alcohol is still useful but not cheese.

Cheese is just one example and perhaps the easiest to understand. There are others that are much more subtle.

An example of this is Kimchi. Kimchi is a fermented food that relies on lactobacillus and other bacteria to create a flavourful preserved cabbage based food. However it can go too far. This is til the same process but it goes too long leading to an extreme flavour.

This one reason why kimchi is kept near frozen cold. The low temperature keeps the fermentation from proceeding. The cold can not reverse what fermentation has already happened.

This is how you can start to separate what is fermenting and what is rotting.