Vinification - Wine Making process

4.1 Viticulture
4.2 Vinification
4.3 Wine Care

4.2 Vinification

Winemaking, or Vinification, is the production of wine, starting with selection of the grapes and ending with bottling the finished wine

Winemaking can be divided into two general categories: still wine production (without carbonation) and sparkling wine production (with carbonation — natural or injected).

The science of wine and winemaking is known as oenology. A person who makes wine is traditionally called a winemaker or vintner.

Vinification of Still wines are done using following process:

Stages / Steps of Vinification –

i) Harvesting

ii) De- Stalking

iii) Crushing Pressing

iv)Fermentation

v) Racking

vi)Fining and Filtration

vii) Sulphuring

viii) Maturing

ix) Bottling

x) Labeling

i) Harvesting

Harvest is the picking of the grapes and in many ways the first step in wine production. Grapes are either harvested mechanically or by hand.

The decision to harvest grapes is typically made by the winemaker and informed by the level of sugar, acid and pH of the grapes.

In the case of the wine maker wanting a sweeter wine, the grapes are left to ripen for a longer period increasing the content of sugar in them. The balance of acidity and sugar is the critical element in the grapes, which gives the taste to the finished wine.

Other factors include grape flavor and tannin development. Tannin is the flavour derived from the seeds, skin and the stalk.

ii) De- Stalking

A de-stalking machine nowadays does the removal of stalks from the grapes. Stalks have a bitter taste due to the presence of Tannin and are removed so that they do not come in contact with the juice.

iii) Crushing Pressing

Crushing is the process when gently squeezing the grapes and breaking the skins to get the “must” (fresh grape juice)

The Must is obtained by Trampling on the grapes, Balloon press, Hydraulic press and Vertical press.

Methods of crushing and pressings are:

a) Trampling

b) Balloon Press

c) Hydraulic Press

d) Vertical Press

a) Trampling

Grapes are placed in large shallow tanks and persons wearing special boots trample on the grapes, crushing them and releasing the must. This was the traditional method before automation and is now done only as Promotional or Publicity event.

b) Balloon Press

This is an expandable balloon fitting in a tank filled with grapes. The balloon is expanded and this gently crushes the grapes against the sides of the tanks releasing the must. This method is used when the wine maker wants less tannin flavour in the Must.

c) Hydraulic Press

This press has a lid on the tank, which descends hydraulically crushing the grapes in the tank and releasing the must.

d) Vertical Press

This press consists of a roller with a plate surrounding it. The grapes are crushed between the roller and plate, releasing the must.

Red wine is made from the must of red or black grapes and fermentation occurs together with the grape skins, which give the wine its color.

White wine is made with Must that is not allowed to come in contact with the skins.

Occasionally white wine is made from red grapes. The Must is extracted and there is minimal contact with the grapes' skins.

Rosé wines are either made from red grapes where the juice is allowed to stay in contact with the dark skins long enough to pick up a pinkish color, or by blending red wine and white wine. White and Rosé wines extract little of thetannins contained in the skins.

iv) Fermentation

Fermentation is the process where the natural yeast on the Grape skin acts on the sugar in the Must, converting it into ethanol and carbon-di-oxide. The carbon-di-oxide is allowed to escape out.

This fermentation is carried out in Stainless steel tanks, which are controlled thermostatically at around 60 to 80 deg. F.

The fermentation can last from 2 days up to 2 weeks. This time is determined by the tradition of the wine making house. The process of fermentation continues as long as there is sugar left in the Must, and until the alcohol percentage reaches 12% - 14%. At this level the ethanol kills the yeast in the Must and fermentation stops.

If all the sugar gets converted to alcohol by this stage the wine becomes a dry wine. If there is unconverted sugar remaining the wine is a sweeter wine. In some cases, sugar is later added to drier wines to make the sweet, during the bottling process.

v) Racking

The fermented wine is transferred to Casks in the next stage, to mature. Lees (dead yeast) collects in the wine over a period of time. The wine from this cask is removed and transferred to another cask leaving the Lees behind. This process is repeated numerous times and is what gives clarity to the wines.

vi)Fining and FiltrationFining and filtration converts the cloudy wine to a clear liquid. A gelatinous substance or fining agent such as egg whites, isinglass or gelatine is introduced into the wine.

This substance attracts all the particulate matter in the wine and settles at the bottom. The clear wine is siphoned off the top and additionally passed through fine filters to further removes any particles.

vii) Sulphuring

Some wine makers add sulphur-di-oxide to the wine as a preservative. Others leave the wine, as it is, preservative free.

viii) Maturing

Wines are matured in Oak casks and the maturing period varies greatly from region to region and for different types of wines.

Maturing makes the wine mellow and smooth and also allows for the wine to acquire a certain colour from the cask in which they mature.

This is also called “Aging a Wine”

ix) Bottling

The wine is then bottled and traditionally sealed with a cork. Today, alternative wine closures like synthetic corks and screw caps, which are becoming increasingly popular.

Some wines continue the maturing process even after bottling.

x) Labeling

Wine labels are important sources of information for the buyer since they tell the type and origin of the wine.

Certain information is ordinarily included in the wine label, such as the country of origin, grading, type of grape, style of wine, alcohol percentage, producer, bottler, or importer.

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Vinification - Wine making process

Beverages Service
Paperback
January 2020 Edition
Author:
Dr. Deepa Prasad Venkatraman
Ulhas Chaudhari

Food & Beverage Services Practical & Techniques
Paperback
January 2020 Edition
Author:
Dr. Deepa Prasad Venkatraman
Ulhas Chaudhari