Conversion of Sugar into Alcohol

The process of fermentation turns sugar into alcohol.

For distilling spirits at home you need an alcoholic liquid, e.g., a fermented mash. Due to empirical data, it is possible to foresee the alcohol content of sugar-containing liquids after fermentation (sugar alcohol conversion), e.g., grape juice, unfermented mash, honey dissolved in water, sugar water, etc. The yeast will have converted all of the sugar into alcohol after fermentation has finished (mash for distilling fruit spirits), thus there is NO sugar left! Another term for sugar or alcohol content is sugar or alcohol concentration. There are, depending on the application, several kinds of units to indicate the concentration of sugar or alcohol.

If you type the sugar content into one of the four stated units and click “Calculate” or press the enter key, the other units will be calculated, as well as the alcohol content. You can also enter the alcohol content and calculate the corresponding sugar concentration. The base of the calculation is the input field with the focus, will say the field where you entered the number or where you click.

Sugar content:

Alcohol content:

Units for Sugar Content

  • Unit
  • Oechsle:

    This unit is the most popular among vintners and cider producers in the German-speaking region. It is a unit for the density (specific gravity).
    Formula: [D] = 1 + [Oe]/1000
    [D]…density [kg/l]
    [Oe]…degrees Oechsle

  • KMW:

    Klosterneuburger Mostwaage: The KMW unit is mainly used in Austria to indicate the must weight, i.e., fruit juice weight.
    Conversion: 1 degree [Oe] = 4,86 * [KMW

  • Brix (wt%):

    Brix is the sugar content indicated in percentage by mass (percentage by weight). This unit is used by the most vintners internationally.
    Conversion: [Oe] = 4,25 * [Brix]

  • g/l:

    Grams sugar per liter: SI-unit (Système international d’unités or metric system) to indicate the concentration of solutions.
    Conversion: [Brix] = [g/l]/((1+[Oe]/1000)*10)
    … and after a short mathematical derivation of the resulting quadratic equation we have:
    [Brix] = (-10 + SQUAREROOT(100 + 4 * 4,25 / 100 * [g/l])) / (2 * 4,25 / 100)

Units for Alcohol Content

  • Unit
  • wt%:

    Percentage by mass (percentage by weight) is NOT a common unit to indicate the alcohol content in alcoholic beverages, but it is common in chemistry and for the sake of completeness it is mentioned here also. In mass percent both solvent and ingredient are specified by weight, so it is mass per mass (weight per weight), therefore other abbreviations are [% m/m] or [% m].
    Conversion: [wt%] = ([% ABV] * DEtOH) / ((100-[% ABV]) * DWater + [% ABV] * DEtOH) * 100;
    [% ABV]…alcohol by volume [-]
    DEtOH…density ethanol: 0.7913 [kg/l]
    DWater…density water: 1.000 [kg/l]

  • g/l:

    Grams ethanol per liter: SI-unit (Système international d’unités or metric system) to indicate the concentration of solutions.
    Conversion: [g/l] = [% ABV] * DEtOH * 10
    DEtOH…density ethanol: 0.7913 [kg/l]

  • % ABV:

    Percentage alcohol bvolume: internationally the common unit to indicate the alcohol content in alcoholic beverages. Other abbreviations are [% vol], [% v], or [% v/v]. In percentage by volume both solvent and ingredient are specified by volume, so it is volume per volume.
    The value is the result of a regression equation, based on empirical data [g/l sugar] → [% ABV], listed in the book The Artisan’s Guide to Crafting Distilled Spirits.

  • US proof:

    [US proof] is actually a historical unit, but regulation permits a statement of proof if it is printed on the label close to the ABV number. In the United States alcoholic proof is defined as twice the percentage of ABV, e.g., 50 [% ABV] is 100 [proof]. Note the difference to United Kingdom: the historical British unit [degrees proof] (the US version is not in degrees) was [% ABV] * 7/4. Therefore 50 [% ABV] will have 50 * 7 / 4 = 87.5 [° proof]. The term originated in the 16th century. Distilled alcohol was “proved” by dousing gunpowder with it and then testing to see if the gunpowder would ignite. Gunpowder would not burn in alcohol that contained less than 57.15 % ABV. Therefore, alcohol that contained this percentage of alcohol was considered to have “100° (one hundred degrees) proof”. The gunpowder test was officially replaced by a specific gravity test in 1816. source: en.wikipedia