Fermentation / Brix /

Brix (°Bx) is defined as the percentage of sugar by weight in a solution. Brix scale 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. 

Specific Gravity - Sugar Conversions

Brix (°Bx) is a graduated scale, used on a hydrometer, which indicates the weight of sugar per volume of solution at a given temperature.

Baume (Bé°) is a hydrometer scale used to measure the specific gravity of liquids. It’s convenient because it gives winemakers an estimate of finished alcohol levels. Both Baume (Bé°) and Brix (°Bx) scales give us a measure of soluble solids in grape juice.

Plato (°P) is a scale that expresses the density as the percentage of sucrose by weight. It’s primarily used in brewing industry to measure density of beer wort in terms of percentage of extract by weight. 

Oechsle (° Oe) scale is measuring the density of grape must, which is an indication of grape ripeness and sugar content used in winemaking. This measure is commonly used by winemakers to decide when to harvest grapes and to predict the maximal possible alcohol level of the finished wine. The Oechsle scale forms the basis of most of the German wine classification.

Specific Gravity - Temperature correction

Hydrometers are used by winemakers to determine the sugar content of wine, grape must and juice, and they're also used in soil analysis. For better accuracy, the reading of the hydrometers must be corrected according to the temperature because the density of a liquid changes with temperature.

This calculator will tell you the actual specific gravity no matter what temperature the sample is.

Fermentation / Nutrients /

Yeast nutrients in a grape juice or must are an important part of any successful and healthy fermentation. The yeast needs supply of carbon, nitrogen, phosphorous also minerals and vitamins as well. These components are naturally present in the grapes, but if they are lacking there is a danger of the production of hydrogen sulphid or problematic fermentation. The simple solution for the lack of nutrients is addition of ammonium compound, such as diammonium phosphate (DAP) or ammonium sulphate and vitamin such as thiamine, which will help increase yeast viability and reduce the risk of lagging or stuck fermentation.

Yeast Assimilable Nitrogen (YAN) Calculator

YAN stands for Yeast Assimilable Nitrogen. Nitrogen is probably the most important macronutrient for yeast after sugar, and is needed to carry out a successful fermentation that doesn't end prior to the intended point of dryness or sees the development of off-odors and other wine faults.

YAN is the combination of Free Amino Nitrogen (FAN), ammonia (NH3) and ammonium (NH4+) that is available for the wine yeast to use during fermentation.

The minimum requirement of YAN for a healthy fermentation should exceed approximately 150 mg/L.

Total YAN should not exceed 400 mg/L since yeast might fail to consume more than this amount, which can create a hazard as other spoilage organisms besides beneficial wine yeast can utilize the nutrients. 

The YAN content should be determined by chemical analysis before making any nutrients addition to the grape must or juice.

Fermentation / Yeast /

Yeast is naturally present on the skins of grapes and they play important role in the fermentation process, converting the sugars of grapes into alcohol. There are also many commercial yeast strains which have different microbiological, chemical, physical and sensory aspects that need to be considered, when winemakers decide which yeast selection to choose, for making different wines. The most important yeast for the wine production is those belonging to the Saccharomyces genus, cerevisiae and bayanus species. The commercial yeast strains are sold in dry vacuum packages or liquid cultures. Dry yeast strains contain viable active yeast cells and they need to be properly prepared for inoculation into grape juice. This is very important step that will insure the yeast efficiency in the fermentation process. There are hundreds of different strains of yeast, which can be use in the winemaking process and each one has their own specific profile, function and characteristics.

Weight and Volume equivalents