The specific gravity of a wine of 12 per cent. is .9843, and by our rule, one gallon weighs about 8.2 lbs. a little less than a gallon of water.
Rule for Reducing Must from a higher to a lower percentage of sugar: Multiply the number of gallons of the must by its specific gravity, and the product by the difference between the given per cent. and the required per cent., and divide by the required per cent.
Suppose that we have 1000 gallons of a must of 27 per cent., how many gallons of water are required to reduce it to 23 per cent?
The specific gravity, by Table I, is 1.1154, and this multiplied by 1000 = 1115.4, which multiplied by 4, the difference between 27 and 23 = 4461.6, which divided by 23 gives 194 gallons, in round numbers.
Rule for Sugaring Must.—If crystallized sugar is used, dissolve it and make a strong syrup, or sugar water, and the proposition is: Given a must of a certain sugar per cent., and a syrup of a given per cent., how much of the syrup for each gallon of must is required to produce a must of any required strength, between the two?
First—Multiply the required per cent. by the corresponding specific gravity.
Second—Multiply the per cent. of the must by its specific gravity.
Third—Multiply the per cent. of the syrup by its specific gravity.
Divide the difference between the first and second products by the difference between the first and third, and the quotient will be the fraction of a gallon required.
Suppose that we have a must of only 10 per cent. of sugar, and a syrup of 60 per cent.; how much of the second should be added to one gallon of the first to produce a must of 23 per cent.?