Industrial fermentation enables homogenous quality
Fermentation is a chemical process, in which sugars are broken down anaerobically with a help of yeasts and converted into alcohol and carbon dioxide. If the conditions are right, fermentation happens spontaneously with airborne yeast. The phenomenon has enabled wine and beer manufacturing for thousands of years.
As this kind of a spontaneous fermentation process is unpredictable and variable, food and alcohol industry has sought help from biotechnology. In industrialized wine production the process of alcoholic fermentation happens under carefully controlled conditions. That enables the homogenous quality of the products.
The procedure of industrial fermentation
Industrial fermentation process in winemaking includes numerous steps that must all be closely monitored:
- Choice of adequate must and yeasts
- Selection of favorable conditions depending on the type of wine desired
- Suppression of the growth of undesirable microorganisms
- Ensuring of the presence of suitable amount of desirable yeasts
- Enabling of yeast growth with proper nutrition
- Controlling of the temperature and preventing excessive heat
- Prevention of oxidation
- Managing of the grape skins in red must.
Selection of yeasts in industrial fermentation
Grapes naturally contain wild yeasts, as well as bacteria and mold. Although wild yeasts can produce unique-flavored wines, the results are often too unpredictable and may even spoil the wine.
In industrial fermentation, the process is often controlled by using predictable cultured yeasts that outcompete the natural yeasts. Yeast strains are selected according to the type of wine desired and the fermentation conditions. Using different strains of yeasts has a great importance to the diversity of wine, even when using the same grape variety.
Yeast also has to be kept active and viable during the fermentation process in order to perform properly. Monitoring the yeast regularly helps predicting the yeast vitality and undertaking corrective actions before the inoculation process. Thus, it enables a homogenous fermentation process.
Controlling the fermentation process
Yeast needs carbon, nitrogen, sulfur and phosphorus, as well as different minerals and vitamins in order to thrive in fermentation. All those components are naturally present in the grape must, but in industrial fermentation their amount is often corrected in an aim of an ideal environment for the yeast. Adding sulfur dioxide in the must inhibits the natural microflora and prevents unwanted by-products.
Another important, and carefully controlled factor in industrial fermentation, is temperature. The temperature has an effect both on the taste of the end product, as well as the speed of the fermentation. An optimal temperature facilitates yeast growth and enables flavors and colors to extract from the grape skins. It also permits the accumulation of certain desirable by-products.
The sugar percentage is controlled during industrial fermentation, as it has an effect on the level of alcohol in the final product. For every gram of sugar converted, about half a gram of alcohol is produced. If the grapes don’t have enough sugar to obtain the desired alcohol level, sugar may be added in the must, but this is strictly subject to local regulations.