Refractometers are used to measure the sugar content of grape must before fermentation. During fermentation, sugars in grape must are converted into alcohol. Pre-fermentation Brix readings are a reliable indicator for the finished alcohol level. Although Brix is a popular sugar scale for winemaker worldwide, there are other scales for measurong grape must. The Milwaukee Digital Refractometers fo Wine and Grape Products measure sugar content is several units to meet the differing requirements found in the wine industry.

MA882 and MA885 convert the refractive index of the sample to sucrose concentration in units of percent by weight, %Brix (also referred to as °Brix). The conversion used is based on the ICUMSA Methods Book (International Commission for Uniform Methods of Sugar Analysis). Since the majority of sugar in grape juice is fructose andglucose and not sucrose, the reading is sometimes referred to as “Apparent Brix”.

MA883 has units of °Baumé. The °Baumé scale is based on density and was originally designed to measure the mass of sodium chloride in water. °Baumé is used in wine making to measure the sugar in must. The MA883 converts the %Brix reading to °Baumé based on the table found in the Official Methods of Analysis of AOAC International, 18Th Edition. 1 °Baumé is approximately equal to 1.8 %Brix, and 1 °Baumé is roughly equivalent to 1 % alcohol when the wine is fully fermented.

In addition to %Brix, MA885 includes two other scales used in the wine industry: °Oechsle and °KMW.
°Oechsle (°Oe) is mainly used in the German, Swiss and Luxenburgish winemaking industry to measure the sugar content of must. The °Oe scale is based on specific gravity at 20°C (SG20/20) and is the first 3 digits following the decimal point. 1 °Oe is roughly equal to 0.2 %Brix.

°Oe = [(SG20/20) - 1] x 1000

°Klosterneuburger Mostwaage (°KMW) is used in Austria to measure the sugar content of must. °KMW is related to °Oe by the following equation:

°Oe = °KMW x [(0.022 x °KMW) + 4.54]

1 °KMW is roughly equivalent to 1 %Brix or 5 °Oe. °KMW is also known as °Babo.

Measuring Method

Different measurements in Wine can be measured with MA882, MA883 or MA885 Digital Refractometers described here.

The MA882MA883 and MA885 are optical instruments that are based on the measurement of the refractive index of a solution. The measurement of refractive index is simple and quick and provides the vintner an accepted method for sugar content analysis.