🍷 Must
Juice of fresh grapes, obtained by crushing or pressing, that has not yet become wine.
Must is the juice obtained from fresh grapes by crushing, draining or pressing, before it turns into wine. In red winemaking it ferments together with the skins and seeds. Under EU rules, grape must may contain no more than 1% alcohol by volume; with more than that, it is called grape must in fermentation.
Must contains water, sugar, acids and aroma compounds. The amount of sugar decides the strength of the future wine: by the OIV formula, about 16.8 grams of sugar per litre give 1% alcohol by volume. Sweetness is measured with a refractometer or a hydrometer.
Yeast, which comes from the berries and the winery or is added, begins the alcoholic fermentation. It turns the sugar into alcohol and carbon dioxide. After fermentation the must becomes wine. If the juice is separated from the skins at once, the result is white wine, and if it stays on the skins, red.
Must belongs to winemaking and is its main stage of preparation. Wine is fermented from it, and must can also be concentrated: the EU defines concentrated grape must as must partly dehydrated without direct heat.
How it connects to Wine
🍷 Must → then → 🍷 Alcoholic fermentation → gives → 🍷 Wine
Links
- Next step
- 🍷 Alcoholic fermentation
- How it is made
- 🍇 From grapes to must, 🍷 Pressing (wine), 🍷 Sorting table
- Who works with it
- 🍷 Winemaker
- Part of
- 🍇 From grapes to must
- In other topics
- 🔄 Fermentation
Frequently asked questions
What is must?
The juice of fresh grapes, obtained by crushing or pressing, that has not yet fermented.
How is must different from wine?
Must has almost no alcohol (EU rules allow up to 1% vol.): alcohol appears during fermentation, when yeast turns sugar into alcohol.
How is the sweetness of must measured?
With a refractometer or a hydrometer.
How much sugar in the must makes 1 % alcohol?
According to the OIV formula, about 16.8 g of sugar per litre of must gives 1 % vol of alcohol in the wine.
Is it true that must is simply grape juice?
Not quite. Must is the liquid from fresh grapes, but for red wine it ferments together with skins and seeds, and EU rules allow up to 1 % vol of alcohol in it; above that it is grape must in fermentation.
What to read next
- 🍷 Winemaker — A winemaker is the specialist who takes wine from the arrival of grapes to bottling, watching fermentation and quality and building the blend.
- 🍷 Pressing (wine) — Squeezing the liquid out of grapes before fermentation or out of the pomace after it; according to the OIV, slowly and progressively.
- 🍷 Sorting table — A table or moving belt where rotten and unripe berries, leaves and debris are removed by hand before crushing.
Similar
🍷 Crushing · 🍷 Destemming · 🍷 Pressing (wine) · 🍷 Pomace · 🍷 Sorting table · 🍷 Maceration
Sources
- Regulation (EU) No 1308/2013 (CMO), EUR-Lex
- Regulation (EU) No 1308/2013, Annex VII Part II: grape must, grape must in fermentation, concentrated grape must, wine
- OIV International Code of Oenological Practices, I.2.1 Grape must
- OIV-OENO 466-2012: evaluation by refractometry of the sugar concentration in musts (sugar g/l x 0.05943 = % vol.)
- Gonzalez R., Morales P. Truth in wine yeast. Microbial Biotechnology, 2022 (PMC)