What does let it ferment mean

Fermentation is a metabolic process where microorganisms (like bacteria, yeast, or mold) convert carbohydrates (sugars) into alcohol, acids, or gases in the absence of oxygen. This process is used to preserve food, create distinct flavors, and produce alcoholic beverages.

Examples include:

• Yeast fermenting sugar to produce alcohol in beer and wine, or carbon dioxide to make bread rise.
• Bacteria fermenting lactose in milk to produce lactic acid, making yogurt or cheese.
• Bacteria fermenting vegetables to produce lactic acid, as seen in sauerkraut or kimchi.