Home-made wines can be divided into two classes:
Country wines, mostly of one main ingredient, such as have been made for many years;
Purpose wines, i.e. wine suitable for specific time or type of meal, or a copy of a commercial type. This calls for a much stricter control of the alcohol produced and the use of a hydrometer is almost essential.
A hydrometer is very simple to use. Although it is used to measure the density of a liquid, it does give a fairly accurate indication of the sweetness of a wine. The hydrometer has a weighted end, and the tube is graduated along its length, usually from 990 at the top to 1170 at the bottom. The reading is the specific gravity, and if a hydrometer is placed in a tall, narrow glass container full of water, it will give a reading of 1000. If placed in a container with some of the liquor just prior to fermentation, it will indicate the amount of sugar present, including the natural sugar in the ingredients. To obtain the true reading, the liquid should be at a temperature of 60°F/15°C, the hydrometer placed in the container and spun gently so that any air bubbles are thrown off. Once there is a true starting gravity, the same procedure will give a finishing gravity, and by taking one from the other, one can assess the alcoholic content by an arithmetical formula. The calculation is quite simple to make, and an example for a table wine is as follows:
First Reading 1080 specific gravity
Final Reading 998 specific gravity
82 divided by 7.36 = 11.1% Alcohol by volume
11.1×7/4 = 19.2% Proof Spirit
In this way it can be seen that if the total sugar content is controlled (i.e. the natural plus the added sugar) the strength of the finished wine can also be controlled and also whether it is likely to finish as a sweet, medium or dry wine. The generally accepted readings for these are:
© 1978 Mary Norwak estate. All rights reserved.