Must weight is a measure of the amount of

sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecul ...

grape A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus ''Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in clusters. The cultivation of grapes began approximately 8,0 ...

juice (

must Must is freshly crushed Juice, fruit juice (usually grape juice) that contains the skins, seeds, and stems of the fruit. The solid portion of the must is called pomace and typically makes up 7–23% of the total weight of the must. Making must ...

) and, hence, indicates the amount of

alcohol Alcohol may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...

that could be produced if it is all

fermented Fermentation is a type of anaerobic metabolism which harnesses the redox potential of the reactants to make adenosine triphosphate (ATP) and organic end products. Organic compound, Organic molecules, such as glucose or other sugars, are Catabo ...

to alcohol, rather than left as

residual sugar The subjective sweetness of a wine is determined by the interaction of several factors, including the amount of sugar in the wine, but also the relative levels of alcohol, acids, and tannins. Sugars and alcohol enhance a wine's sweetness, while ...

.Deutsches Weininstitut: Must weights
, accessed on March 26, 2009

Measurement is in degrees

In France and many other countries, the grape must density is often recalculated to show potential alcohol, the percent alcohol content that would be the result if the must were fermented to a completely dry wine.

Refractometer scales

Brix Degrees Brix (symbol °Bx) is a measure of the dissolved solids in a liquid, based on its specific gravity, and is commonly used to measure dissolved sugar content of a solution. One degree Brix is 1 gram of sucrose solute dissolved in 100 grams ...

(°Bx): Used in

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

, and

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

. * (KMW): Used in

Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...

. The scale is divided into Klosterneuburger Zuckergrade (°KMW). However, the KMW measures the exact sugar content of the must. * Normalizovaný moštoměr (°NM): Used in the

Czech Republic The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...

, and

Slovakia Slovakia, officially the Slovak Republic, is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the west, and the Czech Republic to the northwest. Slovakia's m ...

Hydrometer scales

Baumé scale The Baumé scale is a pair of hydrometer scales developed by French pharmacist Antoine Baumé in 1768 to measure density of various liquids. The unit of the Baumé scale has been notated variously as ''degrees Baumé'', ''B°'', ''Bé°'' and simp ...

(Bé°): Occasionally used in France and by

U.S. The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguous ...

brewers. *

Oechsle scale The Oechsle scale is a hydrometer scale measuring the density of grape must, which is an indication of grape ripeness and sugar content used in wine-making. It is named for Ferdinand Oechsle (1774–1852) and it is widely used in the German, Swi ...

(°Oe): Used in

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

, Luxemburg and

Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...

. It is an important part of the

German wine classification The German wine classification system puts a strong emphasis on standardization and factual completeness, and was first implemented by the German Wine Law of 1971. Nearly all of Germany's vineyards are delineated and registered as one of approxi ...

. *

Relative density Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

: Used in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

(although Brix is sometimes used).

Measuring must weight

Must weights are commonly measured in the vineyard to monitor the

ripeness of the grapes In United States law, ripeness refers to the readiness of a case for litigation; "a claim is not ripe for adjudication if it rests upon contingent future events that may not occur as anticipated, or indeed may not occur at all." For example, if ...

, which helps select the time of harvest. For this purpose, it is usually measured by using a

refractometer A refractometer is a laboratory or field device for the measurement of an Refractive index, index of refraction (refractometry). The index of refraction is calculated from the observed refraction angle using Snell's law. For mixtures, the index ...

. A few grapes are crushed between the fingers and the must is dripped onto the glass of the refractometer. The refractometer will be calibrated in a must weight scale, but as refractometers actually measure

refractive index In optics, the refractive index (or refraction index) of an optical medium is the ratio of the apparent speed of light in the air or vacuum to the speed in the medium. The refractive index determines how much the path of light is bent, or refrac ...

(of the grape must in this case), the must weight scale on the refractometer is in effect an indirect measurement, with refractive indices having been pre-converted to their must weight equivalents.

References

{{reflist Winemaking

Measurement is in degrees

Refractometer scales

Hydrometer scales

Measuring must weight

See also

References