Brix/SG to Alcohol using Alcohol Conversion Factor

Purpose

Use this calculator to calculate potential alcohol based on Brix or SG reading and the alcohol conversion factor.

Background

It has become a rule of thumb to expect that 1 Baume = 1.8 Brix = 18 gm / L sugar = 1 % potential alcohol.But estimating potential alcohol based on grape must Brix or Baume analysis only, is not as straightforward as many people assume.
First, it is important to remember that Baume and Brix do not actually measure a sugar concentration or sugar weight per unit volume.Instead they measure the specific gravity of a solution or a volume measurement only.
Second, only fermentable sugars are converted to ethanol as different yeasts strains have different levels of attenuation, so they will convert different percentages of fermentable sugars to alcohol.
Third, with any one yeast strain, the quantity of alcohol formed varies with fermentation temperature, the extent of aeration and with the Yeast Assimilable Nitrogen(YAN) levels.
The official European conversion ratio is 16.83gm of fermentable sugar per litre for 1 % v / v alcohol.Recent laboratory based investigations, using a standard fermentation environment and a high number of wine yeast strains, have shown differences in sugar to alcohol conversions of no more than 0.51 % (v / v). These results are consistent with sugar to alcohol conversion ratios between approximately 16.5 to 17.2gm sugar per litre for 1 % v / v Alcohol.
For best results to calculate potential alcohol measure the glucose and fructose concentration and use the potential alcohol calculator based on glucose / fructose content in the Alcohol section of Winemaker.Plus.

REFERENCES:

• Predicting alcohol levels (March 2016), Grapegrower & Winemaker magazine Issue 626 - (Winetitles Media);
• Sugar to ethanol conversion by wine yeast - Lallemand Australia Technical Note 803A;
• Measuring Sugar content in grape juice (1997), Concepts in Wine Chemistry by Yair Margalit, Ph.D. - (The wine Appreciation Guild);
• Techniques for chemical analysis and quality monitoring during winemaking (2000) by Patrick Iland, Andrew Ewart, John Sitters, Andrew Markides and Nick Bruer - (Patrick Iland Wine Promotions);