*Brix (°Bx) is defined as the percentage of sugar by weight in a solution. Brix level is important indicator for maturity of the grape. The traditional method for determination of Brix is by using hydrometer, which will measure the density (specific gravity) of the grape juice. For every gram of sugar that is converted during fermentation, about half a gram of alcohol is produced. The different yeasts strains have different levels of attenuation, so they will all convert different percentages of sugar to alcohol.

Both Baume (Bé^°) and Brix (^°Bx) scales give us a measure of soluble solids in grape juice. The Baume (Bé^°) scale is convenient because it gives an estimate of finished alcohol levels. Plato (^°P) is primarily used in brewing industry to measure of the sugar levels in wort and beer. Oechsle (^° Oe) scale measure the sugar concentration in grape must or juice, common in Germany.

*Active dry yeast products consist of viable active yeast cells that directly will affect fermentation process. They are dried under specific conditions to preserve they are viability. There are hundreds of different strains of yeast; each one has a specific profile, function and characteristics.

*Yeast nutrients in a must or juice is an important part of any successful and healthy fermentation. The yeast needs supply of carbon, nitrogen, phosphorous also minerals and vitamins. These components are naturally present in the grapes but their amount may be corrected by adding nutrient products to the must or juice to help increase yeast viability and reduce lagging or stuck fermentations.