sábado, 27 de marzo de 2010

Why my wine fermentation produces vinegar?

Oxygen is considered the principal enemy of wine fermentation process. Ethanol production by yeasts is carried out under anaerobic conditions in the presence of natural sugars such as glucose, sucrose and fructose; however if oxygen enters to the fermentation system, an oxidizing condition is generated. According to organic chemistry, ethanol is transformed in acetic acid following the reaction:

Ethanol + Oxygen (Air) => Acetic Acid

(C2H5OH) + O2 => CH3COOH

Acetic acid is undesirable byproduct due to its unpleasant smell as well as its repulsive taste.

In order to avoid the Acetic acid formation during the fermentation process an oxygen (or air) limiting is desirable. To do this, it is highly recommended the use of check valves in the gas exhaust of fementer, if it is not possible a simple silicone or plastic pipe immersed in water or lime solution is useful to control the inlet or air.