The term for alcoholic fermentation during winemaking used to refer to the apparent "boiling" or "foaming" in the grape must. Fermentation is the microbial degradation of organic matter without the inclusion of external electron acceptors such as oxygen(anaerobic) for the purpose of energy production. In principle, however, organic substances can also be degraded with the inclusion of oxygen(aerobic). For example, acetic acid fermentation consumes oxygen, so it is not a fermentation in the scientific sense as described above. The term fermentation, however, is an umbrella term 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.