There are Twiny circumstances which tend to produce changes in syrups when n3ade, and to cause them to degenerate and become worthless ; these must be carefully guarded agairist. The most common is fermentation ; this may be either the result of too short or too long-continued boiling; or of the presence of an excess of mucilaginous substances; or an imperfect clarification of the syrup will also produce it in the course of time. But the most frequent cause of fermentation is found in leaving the syrup in a warm place, or in vessels which are not completely filled, and especially if they happen to have been wet when the syrup waa introduced. In order to guard against under or over-boiling of simple syrups, it should be laid down as a rule that they stand at 32° B. when boiling, and when cold at 34° iu winter and 35° in summer. They should then be bottled, and stored in a cool cellar.
Lemonade.—The manufacture of lemonade is one of the most extensive and profitable branches of the aerated water trade, and is at the same time extremely simple. The addition of syrups and flavouring ingredients to gaseous water not only does not affect the hygienic properties of the water itself, but frequently enhances them by rendering the water tonic, as well as pleasant to the taste. Lemon or lime juice mixed with simple syrup and aerated water constitutes an agreeable acid and most refreshing beverage. Tartaric and citric acids are also added to lemonade, either separately or together. Their qualities are similar, but not identical, and they are best when mixed together. Citric acid possesses, when diluted with water, a fresh bitter flavour which is very agreeable. Tartaric acid has not so fine a flavour, but it is less costly, and it has also the valuable property of assisting to preserve syrups and lemonades.
The lemon is not the only fruit that is used to flavour aerated waters. Oranges, raspberries, vanilla, and several others are largely employed, each producing a distinct and pleasantly flavoured beverage. The three saccharine aerated drinks most commonly prepared are lemonade, orangeade, and ginger ale. To make the first of these, about half an ounce of essence of lemons is mixed with 1 quart of simple syrup ; orangeade is made by mixing the same quantity of essence of oranges with 1 quart of syrup ; and for ginger ale about the same quantity of essence of ginger is added to the syrup. Another favourite beverage is made by flavouring the syrup with oz. of essence of vanilla. The flavoured syrups thus prepared, are placed in bottles, the quantity added varying in different places, and the bottles are then filled and corked at the machine in the ordinary way.
The regular dose of syrup is from 2 oz. to 22 oz. per bottle.
All the essences used by aerated water makers are usually purchased by the makers ready made, though in many cases it is found desirable to prepare them at the factory. Below are given a few recipes for those most commonly used :— For essence of lemons, remove the outer rinds of 40 lemons, without a particle of pulp, and macerate them with 6 quarts of perfectly pure alcohol at 85°. After two or three days, distil to dryness in a water-bath ; add 2 quarts of water and rectify to obtain 5 quarts of the essence. The essences of oranges and cedrats are made in precisely the same way.
For essence of strawberries and raspberries, take 56 lb. of the fresh fruit, free from stalks and leaves, and place them in 45 quarts of pure alcohol at 80°. Macerate for twenty-four hours in a vessel closed in a water-bath ; add 20 quarts of water, and distil to obtain 44 quarts, each con taining 171 oz. of essence.
Many manufacturers prepare the essences of lemons and oranges by a process of simple infusion without distillation, which is much more readily performed. The outer rinds of twenty lemons are allowed to macerate for eight or ten days in 3i pints of pure alcohol at 56°, which should he perfectly tasteless and odourless. Filter the product, and add 1 oz. to each quart of syrup. The aroma by this method is more concentrated than that obtained by distillation. The essences should be kept in air-tight bottles, and preserved at an ordinary temperature. They improve much by keeping.
The following is the common method for preparing fruit syrups for use at counter fountains in conjunction with aerated water. The fresh fruit, freed from stalks and leaves, is mashed by means of a wooden instrument, and about a fiftieth part in weight of crushed loaf sugar is added. It is then left to stand at an even temperature for a few days until fermentation has taken place. The juice is next expressed, and left to settle in a cool place. When clear, it is simmered for a few moments with nearly double its weight of best loaf sugar, the scum being removed as it forms. If not intended for immediate use, a little spirit should be added. The vessels in which the syrups are placed should be perfectly air-tight ; and in order to prevent the ill effects of variation of temperature they are often stowed away in ashes.