The term for alcoholic fermentation used to refer to the apparent "boiling" or "foaming" in the grape must. Fermentation is understood to be the microbial degradation of organic substances without the inclusion of external electron acceptors such as oxygen(anaerobic) for the purpose of energy production. However, the degradation of organic substances can also take place with the inclusion of oxygen (aerobic). For example, in acetic acid fermentation, oxygen is consumed, which is why this is not a fermentation in the scientific sense as described at the beginning. The term fermentation, on the other hand, is an umbrella term in German for aerobic and anaerobic processes. This often leads to confusion because in other languages "fermentation" is used for alcoholic fermentation or there is no separate term for it.