Even though wine making is the name given to the vinification process of growing grapes, crushing and fermenting; it’s really the fermentation step that transforms regular grape juice, into wine.
Controlling the grape growing process, as well as the harvesting of the fruit will render a high quality grape, with adequate levels of sugar that will thrive during fermentation. A good wine, however, will not only depend of the conditions in which the fruit was grown and treated, but also on the conditions in which it’s fermented.
Fermentation conditions include temperature, flocculation and fermentation time. This conditions will in turn be rule by another important factor, the type of wine making yeasts used, determining what temperature range to use, and how long to ferment your must for the type of wine you are looking to achieve.
General Fermentation Rules
The general guidelines to always take into account during yeast-selection are the following:
Wine Making Yeasts For White Wines
• Yeast must yield a long fermentation process, and
• Yeast must tolerate low temperatures.
Wine Making Yeasts For Red Wines
• Yeast must be heat tolerant, and
• Yeast must endure high levels of Sulphur dioxide.
Wine Making Yeasts For Sparkling Wines
• Yeast must activate quickly and yield a rapid fermentation,
• Yeast must tolerate low temperatures, and
• Yeast must endure medium to high alcohol levels.
Wine Making Yeasts
Wine making yeasts exist in different brands and varieties. While most yeast brands offer similar yeast strains, there are some particular ones that have numerous types of strains specific to the grape varietal that you are using, and the wine style you wish to make.
Active Dry Yeasts
Amongst the most popular wine yeasts are ADY, or Active Dry Yeasts.
Active dry yeasts come in a powdered form, which can be readily used by sprinkling the granules over the must. Like in most yeast use instructions, winemakers suggest creating a starting liquid to wake the yeast and get it working before it’s added to the grapes. In order to do this, the standard practice is to mix the suggested amount of yeast with lukewarm water and a little bit of sugar. Some winemakers use yeast nutrients to supplement the yeast with extra food and energy, adding it at the early stages of fermentation.
Popular brands of ADY include Red Star Active Dry Yeasts, Lavlin Active Dry Yeasts, J. Laffort Active Dry Yeasts and Kitzinger Dry Yeasts. While many of this brands can be readily found in the U.S., they are not as available in the U.K. The most popular wine yeast brands in the United Kingdom include Unican ADY, Gervin ADY and SB ADY.
Liquid Yeasts
There are other types of yeasts that are not offered dried, but in a liquid form. An example of these are Wyeast Vintner’s Choice Yeast Cultures; yet these are sold in large quantities, and may be unsuitable for home brewers who only plan to treat a small amount of wine. The good thing about using liquid yeasts is that their activation time is less than that of ADY’s, and that they are homogeneously mixed in with the must due to its liquid state.
Viekra Dry Yeasts
The last type of yeast to mention is the Viekra Dry Yeasts. These are not ADY, but rather cultures that have been dried on to grape skins, seeds and pulp. Viekra dry yeasts are known to take longer to activate (up to 4 days, as opposed to the standard 2) but they render wines with smoother tastes, and rounder mouth-feel. Viekra liquid yeasts are also available for quicker fermentation processes, with containers yielding up to 10 gallons of fermented must.
Handling Wine Making Yeasts
When handling yeasts, these must be stored in the fridge for proper preservation; or the freezer if you are planning to keep it for longer than 1-2 months. Before using your selected yeast, remember to remove it from the fridge beforehand, and allow it to set at room temperature prior to adding it to the must (or to making a starting liquid.)
If a starter is made, it must be mixed at least a day before the grapes are crushed and the must is prepared. In this way, the yeast is allowed to activate thoroughly, and if the starting mix is not properly blended, a new propagating liquid can be restarted in time before the must spoils.
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