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.
Fruit essences are obtained by macerating the crushed fruits with alcohol, expressing and filtering the liquid and sometimes rectifying it by distillation. The alcohol should not be stronger than 85 nor weaker than 75 per cent. As the fruits contain a considerable percentage of water, the alcohol becomes so far diluted as to furnish essences that are miscible with aqueous solutions. The proportion of alcohol employed for macerating the fruits may vary according to the strength of essence required. We employed usually an equal weight of fruits and alcohol - for instance: Strawberries, crushed, ten pounds; alcohol 85°, ten pints.
An improved essence is made by the addition of some orris root; for instance: Raspberry, crushed, ten pounds; orris root, powdered, four ounces; alcohol 85°, ten pints. Such fruits as apples, pears, pineapples, lemons, oranges (the latter peeled), are sliced, and then crushed on a small scale, on a larger one they are rasped or ground. Pour the alcohol on the crushed fruits and macerate in a demijohn or other suitable vessel (non metallic), tightly closed for a week if possible, then press out on a filtering press or in a linen cloth, filter through filtering bag, and keep the essence in well-stoppered bottles ready for use. No preservatives necessary. The alcohol has absorbed all the aroma of the fruit, coloring and acid, and left behind all albuminous and mucilaginous matter, keeping the essence well preserved. If these essences are rectified in a still or glass retort, a finer product is obtained.
These fruit essences are conveniently made in the season; they are easily clarified and keep well in stoppered bottles. The concentrated essence does not possess a strong odor, which is developed only on dilution. A very small quantity of the essence is therefore necessary for flavoring; to one gallon of syrup about two to three ounces are required, making a fine class of beverage with the true aroma of the fruit.