The second essential step in winemaking is to add additional ingredients to the base and ferment in a primary for 3 to 10 days at 70-75 degrees Fahrenheit.
Unless we use boiling water or direct heat for flavor extraction, or unless we use pasteurized juice or frozen concentrate, it is important that the must be protected against bacteria and mold from the earliest moment, and against oxidation. We do this by adding sulfites to the must in the form of crushed and thoroughly dissolved Campden tablets or powdered potassium metabisulfite. This does not sterilize the must, but brings it to an aseptic level of protection against microscopic organisms that can do terrible things to wine. Just as importantly, the addition of sulfites creates both bound and unbound (free) sulfur in the must. The later occurs most notably as sulfur dioxide gas, which tends to fill the spaces between molecules of solid and liquid matter in the must. This is real important, because those spaces are normally filled with oxygen atoms and they react with other molecules in the wine to eventually reduce it to something undrinkable. Oxidation is the death-blow for all wine, so getting rid of that oxygen and replacing it with sulfur dioxide helps protect and prolong the life of the wine. But it also retards the tendency of all white wines to turn brown and red wines to turn brickish (reddish-brown). Finally, they also inhibit the early growth of most wild yeasts that find their way into musts (on the skins of grapes, fruits, berries, flowers, leaves, and other natural ingredients), while cultured wine yeasts are largely sulfite tolerant. This allows the cultured yeasts to grow quickly without competition and dominate the must. So, even if the recipe doesn't say to add sulfites, add them as early in the process as practicable. They can even be added to warm (but not hot) must. The normal dose is one crushed and dissolved Campden tablet to each gallon of must, or 1/4 teaspoon of potassium metabisulfite to each 5 gallons of must. Do not add more than this, as too much is in some cases worse than not enough.
Pectic enzyme is an additive to most fruit and berry musts. It not only breaks down natural pectin found in most fruit, but also helps break down the cell walls in the pulp and skins and make it easier to extract the flavors, aromas, acids, tannins and other and components that contribute to the complexity of finished and aged wines. It is best to wait a few hours after adding sulfites (Campden tablets or potassium metabisulfite) before adding pectic enzyme, as its action is retarded by an excess of sulfur dioxide. After 8-10 hours, however, it is quite safe to add it. It comes in either liquid or powdered form. The liquid is more concentrated and preferred by commercial winemakers, but it has a very finite shelf life and must be refrigerated to even achieve that. It also varies in strength from different manufacturers and cannot be reliably included in recipes, whereas the powdered form is fairly constant among manufacturers, does not require refrigeration, and can be kept for several years without losing its ability to reduce pectin. Pectic enzyme works best at cooler temperatures. Do not add it to musts above 75 degrees F.
Except for perfectly ripened wine grapes, most musts require acid adjustment to achieve balance. Some fruit and berries contain too much acid and need dilution with water to bring their acidity to acceptable levels. But most are acid-deficient to begin with and acidity needs to be added. Recipes most generally call for the addition of acid blend, which is a mixture of citric, malic and tartaric acids in crystalline form. Many recipes, especially older ones, use citric acid in the form of orange or lemon juice (or both). One can buy crystalline citric, malic and tartaric acids. These have very long shelf lives and can be used to change the acid profile of a wine, especially the finish and after-taste. Acids can be added at any time before yeast inoculation.
The bite in wines is produced by tannin, a natural component of most fruit and berry skins, seeds and stems. But most white wines lack sufficient tannin to produce a bite, and so tannin is generally added in small amounts to help balance the wine's astringent side. Do not overdo it. A 1/8 to 1/4 teaspoon amount is usually sufficient to give the wine that "something" it needs. Tannin is usually either grape or gallic in origin. Grape tannin is preferred. It is brickish in color and has a shelf life of many years. But it does not dissolve well if added to liquid. Add it to a clean juice glass and then pour a little water or fruit juice in on top of it. Stir it briskly with a fork or small whisk to dissolve it and pour that into the must.
Except for well-ripened wine grapes, almost all other winemaking bases lack the nutrients required by yeast to produce a good, thorough fermentation. Yeast nutrients contain a variety of trace minerals, but especially nitrogen. For a sterile must (one without any natural nutrients whatsoever), 1-1/2 to 2 teaspoons of nutrients per gallon of must might be required, but for most wines made from other than wine grapes, a teaspoon of nutrients is sufficient. Do not mistaken yeast energizer for yeast nutrients. Energizer is used rarely and then sparingly, with only 1/4 teaspoon per gallon being sufficient to do what it is meant to do. It is rarely added to a must before the beginning of fermentation (an exception is for blueberry wine) and is really only called for when a fermentation turns sluggish (slows considerably while still possessing plenty of unfermented sugar) or sticks (stops fermenting while still possessing considerable unfermented sugar) altogether. It is not a substitute for yeast nutrient.
Sugar is essential for making wine, as without it the yeast will not produce alcohol. Natural sugars in the fruit, berries or juice are often insufficient to produce anything stronger than a weak cider. Most recipes simply call for sugar. This means white, granulated cane or beet sugar. Do not use powdered sugar at all, and only use brown or raw sugar in small quantities unless a larger amount is specified in the recipe. Corn sugar can be used in direct proportions to granulated. Fructose (fruit sugar) is sweeter than other kinds and should be used only when a sweet wine is desired or in sweetening a wine after fermentation. Honey can be used in lieu of sugar, but use 1-1/4 pounds of honey for every pound of sugar called for. Be sure to check the Glossary of Winemaking Terms on this web site for each of these additives, including sugar.
Another essential ingredient found in every must is water, whether added by the winemaker or contained in the juice to be converted to wine. It is not recommended that distilled water be used at all, with the possible exception of topping up a carboy with too much air space between the wine and the bung/airlock. If your local tap water tastes bad enough to require you to buy bottled water for consumption, then at least use spring water in your winemaking. Distilled water contains none of the trace elements essential to yeast health, while spring water always contains what yeast need. This need is in addition to trace elements included in yeast nutrient. If your tap water is biologically untrustworthy (contains microorganisms detrimental to your health), then by all means do not use it unless you bring it to a full boil for 10 minutes first. Do not top up with recently boiled water -- allow it to cool down to room temperature first, as yeast die at 104 degrees F.
Yeast make the wine and therefore are essential to the process. If you use fresh ingredients, such as fruit, berries or herbs, yeast will come into your wine from outside naturally. They also float in the air in almost every kitchen, so that a fruit juice left uncovered for an hour on the kitchen counter will collect a culture. Neither of these yeasts should be used in making wine, nor should baking (bread) yeast. The yeast on fruits and berries are wild, and probably contain strains of yeast unsuitable for wines. Some produce off-flavors and odors, while others only produce small amounts of alcohol. Yeasts found in the kitchen air are generally bread yeasts and also do not make enough alcohol for most table wines. More importantly, molds also float around in the kitchen and will ruin an otherwise perfect must. Inhibit these yeasts with sulfites and inoculate your must with cultured wine yeast strains. Hydrate the active dry yeast (ADY) cultures in a starter solution and allow them time to begin reproducing themselves. The more yeast you add to your must, the sooner they will convert it to wine. A 5-gram sachet (packet) of ADY is sufficient to inoculate a 1- to 5-gallon batch, but if you allow it to begin in a good starter solution it will double in population in about two hours. During the first 48-72 hours in the must, the yeast population will double many times. See The Miracle of Yeast for more, including how to make a starter solution.
Always begin fermentation in a primary, without an airlock, unless specially instructed to begin in a carboy. The inoculate (yeast culture added to the must) needs exposure to oxygen for the first 48-72 hours to assist the yeast in rapid reproduction and increase the population to a density suitable for rapid fermentation. If the must has been sulfited, they need the large surface area to take in the oxygen needed. The top of the primary need only be covered with a clean cloth of tight weave, such as muslin, held in place with an elastic band. If you have a primary with rigid lid drilled for an airlock, use the lid but plug the hole with a ball of cotton for the first few days.