This section is from the "Elixirs And Flavoring Extracts. Their History, Formulae, & Methods of Preparation" book, by John Uri Lloyd. Also available from Amazon: Elixirs and flavoring extracts,: Their history, formulae, and methods of preparation;
The quality of these extracts is governed by the freshness and quality of the oil of lemon employed in making them, for, as a rule, the extract of lemon used in flavoring is made from the oil. If the oil be old, it is likely to acquire a turpentine-like odor; and even though of moderate age, it often loses its fresh lemon sweetness and becomes harsh. Oil of lemon, like vanilla beans, may be obtained in commerce of different qualities and at different prices. Those proposing to make flavoring extracts of lemon from the oil should pay special attention to its quality. There is little economy in purchasing cheap oil of lemon. At the present time it is possible to obtain this oil (hand-pressed is the best) of unquestionable purity. The pharmacist may, as a rule, depend upon the statement made by the jobbing druggist concerning the quality of the oil, and, if he is willing to pay the price demanded for a first-class oil, he can readily obtain it. We will add that it is not always possible (without great experience) to prejudge the value of oil of lemon by the odor. Upon the contrary, it is possible for an oil of lemon that has a very pleasant odor to produce an extract that shows evidence of turpentine, especially after having been mixed with syrup.
Oil of lemon, 1 fluidounce
Alcohol, 15 fluidounces.
Mix them together, and after a few days filter if a precipitate forms. Then color to suit the taste with a little tincture of curcuma.
Oil of lemon, 1/2 fluidounce.
Alcohol, diluted alcohol, of each a sufficient quantity.
Mix the oil of lemon with eight fluidounces of alcohol, then add diluted alcohol until a cloudiness appears, after which add of alcohol a sufficient quantity to make sixteen fluidounces. Then color to suit the taste by the addition of a sufficient amount of tincture of curcuma.
Oil of lemon, 1/2 fluidounce.
Diluted alcohol, 12 fluidounces.
Alcohol, a sufficient quantity.
Rub the oil of lemon in a mortar with carbonate of magnesium in quantity sufficient to form a cream, then add the diluted alcohol and filter. To the filtrate add enough alcohol to bring to the measure of sixteen fluidounces, and color to suit the taste with a sufficient amount of tincture of curcuma.
Grate off the outer rind of four lemons. Put this into a wide-mouth bottle and pour upon it a pint of alcohol, and add thereto one-half fluidounce of fresh oil of lemon. Macerate, with occasional shaking, for four days, and filter. color the filtrate to suit the taste with a sufficient amount of tincture of curcuma.
To a pint of any of the foregoing flavoring extracts of lemon add one fluidrachm of oil of lemongrass. This is a pleasant addition in some instances, as there are persons who find the mixture of lemon and lemongrass to form a gratifying flavor. However, in our opinion, the extract made with a prime quality of oil of lemon is not excelled.