Wine production
Wine is an alcoholic drink typically made out of fermentation of grapes. Mostly wild yeast or specific strains consume sugar converting them into ethanol and carbon dioxide releasing heat.
Viticulture
Factors which influence grape’s flavour:
climate of the vineyard’s region
drainage around the vines
humidity of the region
sun exposure.
soil quality
Steps involved in wine production
Harvesting
Grapes are picked up by hand or mechanically.
Degree of maturation is informed by the level of sugar and acid.
Stemming
Stemming is the separation of the stems and grapes. Stemmed grapes are sent to the press.
Crushing
A horizontal press squeezes the grapes, separating the fresh juice (must) from the skins (marc). After crushing, the fermentation process starts.
Fermentation
Sugar and acids naturally react with wild yeasts. Every so often, vineyards add their own yeasts.
Fermentation can take from 10 - 30 days to convert natural sugar to alcohol.
Draining
Liquid wine is drained off the vat without being pressed and collected into barrels (free-run wine). The remaining pulp retains about 20% of the wine.
Pressing
The remaining pulp after draining, is pressed to squeeze out the press wine. The press wine tends to be dark, harsh, and unpalatable and is mixed with free-run wine to an acceptable level.
Mixing
The free-run wine and press wine, always from the same source, are mixed together in appropriate ratios to obtain the desired balance.
Clarification
Clarification is the step of stabilization of the fermentation process.
During clarification, all remaining solids are taken away from the fermented liquid.
Clarification is done in numerous ways:
addition of substances that cause the solids in liquid to adhere to one another and sink to the bottom of the vat (Fining)
running the liquid through coarse and fine filters
siphoning the liquid off the top of the fermenting vats after the solids have settled to the bottom
Aging
The final stage involves vinification.
•At this stage, the clarified wine is transferred either into wooden barrels or into metal vats, in which the wine is allowed to mature further and develop flavours.
• Aging the wine in wooden casks, it will allow the wine to pick up flavours from the wood, adding greater depth to its flavours.
• This can add body to some wines.
Yet keep in mind that the “woody” flavor isn’t favoured by all types of wine; hence the use of metal vats is considered.
Oak aging
Sur Lie Aging
The process allows a finished wine to continue to sit on the lees in order to extract flavours.
*Means “on the lees” (Lees are the spent yeast cells that fall to the bottom of the fermentation vessel)
*Usually done for Chardonnay
*Adds a creamy, toasty dough-like flavour to the wine.
*Wine can be aged on the lees for 3-6 months.
*Lees are stirred every other week to improve their exposure to the wine and make the flavour more pronounced
Whites
*Once the fermentation is done, the wine is left in the barrel to age sur lie
*After sur lie aging, the wine is “racked” off the lees into a clean barrel and allowed to age for 3 - 6 more months
Reds
*Reds are usually not fermented in new oak barrels but in stainless steel or old wooden vats.
*After fermentation and pressing, the wine is put into small oak barrels to age.
*Aging takes anywhere around 8 months to 2 years (softening of tannins)
Bottling
Bottling is the final step involved in wine production.
A dose of sulfite is added to preserve the wine and prevent unwanted fermentation in the bottle.
Then the bottles are traditionally sealed with a cork. However, alternative wine closures such as synthetic corks and screw caps, which are less susceptible to cork taint, are becoming increasingly popular.
Steps involved in red wine production
A) Harvesting
B) Stemming/ Crushing
C) Fermentation
D) Secondary Fermentation (optional)
E) Pressing - JUICE IS SEPARATED
F) Aging
G) Filtering
H) Bottling
Steps involved in white wine production
A) Harvesting
B) Stemming/ Crushing
C) Pressing - SKINS ARE REMOVED
D) Fermentation
E) Secondary Fermentation (optional)
F) Aging
G) Filtering
H) Bottling
References
Wine 101 Welcome MMBA Members - Municipal Bev. http://municipalbev.com/articles/wine/wine101.pdf
PPT - Wine Production Yoann Chelin PowerPoint Presentation ... - SlideServe. https://www.slideserve.com/yoko/wine-production-yoann-chelin
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