Grape must

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Black-blue berries with a cross section of a berry. Red dyes are only found in the berry peel

Grape must ( lat. Vinum mustum "young wine") is the juice obtained from grapes by pressing . It is the raw material for making wine and sparkling wine, grape juice ( sweet grape must ), fruit juice , sweet reserve, must concentrate and rectified grape must concentrate (RTK). It can be made from white or red wine varieties.

Must ingredients

Grape must contains on average:

  • Water 780-850 g / l
  • Carbohydrates (sugar) 120–250 g / l. The most important sugars contained are glucose (grape sugar) and fructose (fruit sugar). Sucrose (cane sugar, beet sugar) can be contained in small amounts. Non-fermentable sugars (pentoses) are contained in small quantities.
  • Acidity 6-15 g / l. The tartaric acid is the most important acid in the must. It also contains malic acid and small amounts of citric acid.
  • Minerals (ash) 2.5–5 g / l such as cations: potassium , magnesium , calcium , sodium . Anions: phosphate , sulfate , chloride , carbonate and, in small amounts, boron , manganese , zinc , iron .
  • Nitrogen compounds 0.2-1.4 g / l
  • Polyphenols (tannins, dyes) 0.1–2.5 g / l
  • Flavorings
  • Vitamins : in the berry and grape juice, vitamin C ( ascorbic acid ) in an amount of about 20-50 milligrams / liter, vitamin B ( thiamine ) in an amount of about 0.2-0.5 milligrams / liter.
Contains 100 g of grapes
Calorific value water fat potassium Calcium magnesium vitamin C
286–297  kJ (67–71  kcal ) 81 g 0.5 g 192 mg 18 mg 9 mg 4 mg

Must yield

It is mainly obtained by pressing, grinding or squeezing. However, part of the must is already pressed out by the weight of the grapes. It is known as forward must and is considered to be particularly valuable. The must then obtained by pressing is called press must . Since the quality decreases with each pressing process, the press must usually only refers to the yield from the first pressing; the yield of the later pressings is called failure must .

Depending on the degree of ripeness and the liquid content of the grapes, 100 parts of grapes produce between 75 and 80 parts of must. The remaining solid components when the mash is pressed (skins, seeds, stalks) are called grains or pomace .

Depending on what is to be produced from the grapes, different processing takes place.

Contains alcohol

Wine, sparkling wine, sparkling wine

The largest proportion of white and red wine grapes is processed into wine (and other products made from it). For winemaking see:

Main article: Cellar management (oenology )

Main article: White wine production

In red wine production, the mash is fermented (mash fermentation) or heated.

Main article: Red wine making


Sweet grape must

Must balance: 0… +130 ° Oe at +20 ° C

The processing of grapes into grape juice differs from wine production in that a product is produced that is more susceptible to oxidation and microorganisms, and that the use of SO 2 has to be avoided. The lack of protection has to be made up for by working quickly and cleanly. Only absolutely healthy grape material is to be used. Injured and rotten grapes tend to have more enzymes and thus more browning. The volatile acid content is also increased. Rotten grapes have a higher content of patulin , a mycotoxin (limit value 50 µg / l). For reasons of taste, grapes used for the production of sweet must should have a favorable sugar / acid ratio (13–15 ° KMW = 65–75 ° E and 8–13 g / l total acid).

Maximum alcohol limit: 3 g / l (EU)

Processing steps in commercial sweet must production (with naturally cloudy grape juice, some points for clarification are omitted):

  • Harvest early in the morning to cool the grapes for processing.
  • No maceration time.
  • In the production of red grape juice, the mash is briefly heated to 80–85 ° C or 2–3 hours to 55–60 ° C to get the color out of the berry skins.
  • Use of pectinases to improve self-clarification and filtration.
  • Prevention of protein clouding through bentonite treatment .
  • Possibly improvement of the clarifying effect and the filtration performance Implementation of a silica sol gelatin fining.
  • clarification
  • A tartaric stabilization can be achieved by two days Storage in the tank at 0-2 ° C. Otherwise it makes sense to refer to the natural process of tartar deposits on the label.
  • Microbiological stabilization through pasteurization at 80 ° C.

Use as:

White or red sweet grape must .

Mixing partner for mixed juices such as B. multivitamin juice u. a.

Further processing into concentrated grape juice and rectified grape must concentrate (RTK) and sweet reserve .

Grape syrup

Grape thick juice is a highly concentrated , thick grape must. Thick juice is characterized by a higher sugar content and lower water content .

Use in wine production (according to EU regulation No. 606/2009):

  • Fortification (alcohol increase)
  • Remaining sweetness award

Rectified grape must concentrate (RTK)

Rectified grape must concentrate (RTK) is the liquid, non- caramelized product that is produced by rectification and extensive dehydration as well as other approved treatments to remove the ingredients other than sugar from grape must. It is a highly concentrated sugar syrup made from grape must.

Use in wine production (according to EU regulation No. 606/2009):

  • Enrichment (improvement of grapes, increase in alcohol)
  • Remaining sweetness award

Sweet reserve

Sweet reserve is a specially treated, storable grape must for subsequent sweetening (addition of a few grams / l sugar) of wine; the sweet reserve may contain a maximum of 1% alcohol by volume .

The use of a sweet reserve gives the wines a distinctly different character (depending on the amount added) and is therefore rarely used. Production and storage are also costly. RTK is mainly used to sweeten the wine .

Various processes are used for preservation ( sterilizing filtration = cold sterile storage , hot storage , short-term heating (KZE) , the Seitz-Böhi process ( cross-flow microfiltration ), silent sulphurisation and storage with the addition of sorbic acid and sulfur dioxide ); almost always 25–100 mg / l sulfur dioxide (SO 2 ) are added.

Web links

Wiktionary: Grape must  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ^ Robert Steidl: Cellar economy. 7th edition. Österreichischer Agrarverlag, Vienna 2001, ISBN 978-3-7040-1699-7 .
  2. EU Nutritional Labeling Directive (EU NWKRL 90/496 / EEC) & Rewe nutritional table
  3. a b must. In: Retrieved June 12, 2017 .
  4. a b Austria Wine - Precious Culture - News & Media - LP: From "Landwein" to "Pressmost". In: Retrieved June 12, 2017 .
  5. a b Entry on sweet reserve. In: Römpp Online . Georg Thieme Verlag, accessed on June 22, 2015.