See the notes (and example) below the tool for some tips concerning simplified sugar, water and acid corrections of juices

Juices are produced by crushing and pressing fruit or grapes. The pressing process separates the skins from the juice. Juices normally contains considerable amounts of pulp but no seed, skins, stems etc. Juices packaged as beverages should never be used for making wine. They normally contain additives that inhibit fermentation and seldom have enough sugar. Juices for wine production need to be almost 25 percent sugar by weight (which is too sweet for most people to drink) and are more like syrups than a beverage. If the material you are fermenting contains skins it is not a juice, it is a must. In that case, use one of the other tools suitable for fruit and grape musts.

Tannin is found in grape skins and in the skins of a few fruits like blueberries.,loganberries and blackberries. Since juices are separated from the grape or fruit skins by the pressing process, wines made from juices typically do not have significant amounts of tannin. If the wine being fermented is red, grape tannin should be added, particularly if the wine will be high in alcohol and acidity for wine stability and a balanced taste. Addition of tannin allows minimal amounts of sulphite to be added in order to provide stability. If the wine being made is white or rose, then tannin is not normally added. But in this case, to prevent spoilage and oxidation, the amount of sulphite that is added should be the correct amount for a white wine. The guidelines produced by the sulphite tool may be used. A normal nutrient addition should be made when making juice wines. For red wines from low-tannin juices typically one can add 1 teaspoon (5 [ml]) per every 5 liters of juice before fermentation. See the fruit wine design tool for more accurate amounts to add to red wines made from different types of fruit (or mixtures). Many fruits contain pectin (especially apples). Fresh pectic enzyme may be added to prevent hazes. Use the amounts recommended in the fruit wine design tool or follow the recommended amounts (see package etc.) for the enzyme you are using.

Basic Sugar and Acid Corrections Tool for Fruit and Grape Juices

Increasing the amount of sugar in the juice will increase the juice's specific gravity (SG) and the alcoholic strength of the finished wine.

Increasing the amount of water in the juice will decrease the SG and alcoholic strength and will also decrease the total acidity of the finished wine.

If total acidity has to be reduced by the addition of water, then some added sugar may be needed to maintain a reasonable amount of alcohol. Remember that at least 10 percent alcohol by volume is required to protect the wine from spoilage organisms. And the higher the alcohol level the more stable the wine will be. Remember also that wine should contain at least 6 grams per liter (measured as tartaric acid equivalent) of total acidity to prevent a dull taste and to protect against organic spoilage. White wines are more subject to spoilage and typically have a few grams more per liter (7 or above). Another type of acidity measurement is know as "pH". This is of even more importance in preventing spoilage, but in the case of pH, low values are better. Another tool (the sulphite tool) provided for calculating reasonable amounts of sulphite. It uses the pH (if available) to determine optimal amounts of this vital addition (potassium metabisulfite) which assists yeast to compete with bacteria and molds, prevents spoilage and reduces oxidation.

Increasing the amount of tartaric acid (or acid blend) with increase the total acidity of the finished wine by the amount shown. It is assumed that the juice contains mainly tartaric and malic acid (the usual composition for grapes). For citrus or other types of fruit, it is better to use the fruit wine composition tool in order to find the amount of acid, sugar and water to add. This is because fruit other than grapes typically contain acids that are partly or entirely consumed by yeast in the fermentation. In addition, certain other vital components such as yeast nutrients and tannins are not present in most types of fruit. Fruit wines are best made by recipes based on the experience of experts encapsulated in the fruit wine design tool.

Each type of wine yeast has a particular level of alcohol which it can tolerate before it stops fermenting. Some special types of yeast can reach over 20 percent alcohol, particularly if the extra amounts of sugar required to do this are fed slowly into the secondary fermentation and other conditions such as nutrients, temperature and acidity are close to optimal. It is much more usual for yeast to stop fermenting at about 15 percent alcohol.

If sugar remains when the yeast stops fermenting, the wine will be sweet. Most producers of wine yeast make this information available. Ask where you buy your yeast if this information is not available on the package. Many books contain charts or tables with this type of data. See our book reviews for examples. The tool for simple sugar and acidity corrections uses the input (or default) fermentation limit to predict the finished wine's sweetness (in the usual units of grams per liter). Remember that each 1 gram per liter means 0.1 percent (by weight) of residual sugar. See also the tool for measuring percentage alcohol of a finished wine which attempts a more sophisticated prediction of residual sugars. The advanced corrections tools have an entry so that the user can specify the fermentation limit (percentage alcohol) at which it is anticipated the yeast will stop fermenting. If you use a proper wine yeast, the fermentation should normally proceed beyond the normal 12 or 13 percent alcohol most people prefer in a wine provided that the acidity is not too high and nutrients are available. Yeast also may quit working at higher alcohol levels if the temperature is too low. Yeast like "average" conditions and and you will reduce the chances of stuck fermentations if you let them ferment near room temperature and with moderate levels of acidity and make sure you start with enough nutrients to support a robust yeast population. Never add less than the amount of yeast recommended on the package and it does not hurt to add a bit more.