This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
The substance and body of the beer is composed of three parts, and requires to be well proportioned. First, the extract, which gives the flavor or bouquet and body to the beer; second, the sweetening; and, third, the water. The amount of sweetening required varies somewhat with the amount of fermentation desired. The yeast, as is well-known, converts a certain amount of the sweets into carbonic acid and alcohol, and this in time will be converted into acetic acid and make the so-called sour beer, and afterwards vinegar.
Fermentation, consequently, uses up the sweet; therefore more is required than for beer made with soda water, or carbonated beer, as it is called. About three-fourths of a pound of brown sugar to each gallon of water is usually sufficient; but if the beer is to be kept for some time, which, of course, requires a smart working, a little more would be required. When white sugar is used, as it always should be in fine flavored beers, like lemon, spruce, birch, etc., seven-eighths of a pound to the gallon of water will not be too much with a good, smart fermentation. If the fermentation is weak and poor, this amount of sugar will make the beer taste too sweet and flat, but not otherwise.
When molasses is used for sweetening, a pint for a gallon and a half of water is sufficient, or one gallon to eleven of water. Molasses cannot be used in fine-flavored beers, such as lemon, birch, etc. With a strong, pungent extract, like sarsaparilla or spruce, and well fermented, it can be made into a very good beer at a small cost. Refined sugar is the hardest to ferment; it requires a better yeast, more of it, a higher temperature and a longer time; but the beer made therefrom is considerably better, and will also keep sweet a much longer time. A small amount of grape sugar, not more than one pound in ten, aids in fermentation very much where white sugars are used, and also keeps the beer alive and sweet a longer time, without increasing the expense. During the process of fermentation, cane and each other variety of sugar is first changed into grape-sugar (glucose), and then ferments; hence it is a distinct disadvantage to use glucose for carbonated beverages, but the partial substitution of the best glucose for cane-sugar in this class of drinks is, therefore, not detrimental, where cheapness is a consideration.