wine production

Hard work in vineyards culminates with the harvest. In Moravian regions, the harvest period is in September and October, depending on wine varieties, location of the vineyard and the weather. Late varieties with higher acidity (Rhine Riesling, Welschriesling, Pinot and Frankovka) are picked in November, when malic acid has turned into sugar and aromatic substances resembling overripe grapes begin to form. Healthy grapes are the basic prerequisite for the production of quality wines and quality wines with predicate. The grapes are processed on the day they are harvested in order to avoid heating and fermenting and the formation of unwanted bacteria.

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Fast and careful processing of grapes is essential. The production methods of white and red wines are different.


crushing and primary fermentation

Grapes are separated from the stems and crushed at the same time. This prevents the must, i.e. the future wine, from being contaminated with bad substances. The wine crusher has a hub with blades that push the crushed grapes through a stainless-steel sieve. Special pumps drive the mashed berries into barrels. A small amount of sulphur dioxide is added to the mash in order to prevent it from being infected by bacteria, and the mash is then left to ferment for 12-24 hours, with red wines for several days. This enables the extraction of needful substances and guarantees a higher content of extractivity, bouquet substances and pigments.


pressing

Pressing separates the liquid from solid substances under pressure. The must flows through the fine pores of the press. Average pressing capacity is about 70%. It is important not to crush seeds and stems during the crushing and pressing as the must would then contain too much tannin and tanniny substances. To measure the amount of sugar in the must, a standardized mustmeter (also saccharometer, abbreviated “NM” in Czech) is used. The mustmeter shows how many kilograms of sugar are in a hundred litres of must. The wine law only allows the sweetening of quality wines with beetroot sugar, wines with predicate must not be sweetened. 1 ČNM degree equals the addition of 1.1 kg sugar for every 100 l of must.


Quality categories:

  • quality wines with must density up to 19°ČNM
  • cabinet wines, must density over 19°ČNM
  • late harvest wines, must density over 21°ČNM
  • selected harvest wines, must density over 24°ČNM
  • selected berries harvest wines, must density over 27°ČNM
  • straw and ice wines, must density over 27°ČNM
  • selected dried-berries harvest wines, must density over 32°ČNM

fermentation

With high contents of acids, especially malic acid that creates a robust flavour, winemakers use bacteria that convert malic acid into the smoother lactic acid and carbon dioxide. This process is known as the biological elimination of malic acid. When the sediment (dead yeast) has settled, the wine is poured into vessels. Long-term contact with the sediment might spoil the quality of the wine. To speed up the process of wine-clearing, fining agents such as bentonite, egg whites, potassium casseinate and gelatin are used. This step removes proteins from the wine. When the coagulated proteins have settled, the wine is filtered. Its flavour, aroma and character are formed in this phase. The length of the aging process varies, depending on the variety, year and chemical composition of the wine. White wines achieve optimum quality after several months, while red wines acquire their typical properties after a longer storage (2-3 years), ideally in barrels. Aging in oak barrels has a positive effect on the quality and harmonization of wine.


filtration

Settled sediments are removed by means of siliceous or cross-flow filters. Bottling is preceded by sterile filtration during which wine flows through cellulose boards, which removes sediment particles and bacteria.


bottling

This step is preceded by several essential measures:

  • sensory assessment of wine
  • adjustment of the content of sulphur dioxide
  • test of protein stability
  • stability of wine towards tartaric
  • clarity