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Citric Acid Syrup
Citric Acid Oil Lemon ¼ Troy ounce 4 minims or drops Simple Syrup (7½ pounds sugar in a finished gallon syrup), 2 pints.
Rub citric acid to a fine powder in mortar, add oil lemon and small quanof syrup; 1 to 2 tity of syrup; 1 to 2 ounces. After thoroughly mixing, add remainder of syrup gradually. Now add bicarbonate potash, the solution of bicarbonate magnesia and citric acid, the solution of bicarbonate magnesia and citric acid, 5¾ pints distilled water; shake vigorously; put fountain together without waste of time. Force in 50 to 75 pounds of gas, and dispense this in mineral water tumblers at 10 cents. We recommend the use of American Concentrated Syrups, as they require no compounding, except dilution with simple syrup. The best formulas for their use will be found under their proper headings.
A druggist's lemon-flavoured fountain syrup, built on citric acid rather than juice. The printed text is a conflation of two separate formulas — the syrup itself ends at "add remainder of syrup gradually," and everything after that belongs to a charged-water procedure for a soda fountain, not to the syrup.
- Read the second half as a different formulaThe passage from "Now add bicarbonate potash" onward is a mineral-water charging routine that has been run together with the syrup, with a line of type duplicated. Nothing in it is needed to make the lemon syrup.
- Troy ounceApothecary weight: a troy ounce is 31.1 g, so a quarter ounce is about 7.8 g of citric acid. That is a little heavier than the familiar avoirdupois ounce; here the book specifies troy outright.
- MinimsA minim is one sixtieth of a fluid drachm, roughly 0.06 mL. Four minims of oil of lemon is about a quarter of a millilitre — a scant five drops from a dropper. Essential oils of citrus are strong enough that this is a real quantity, not a rounding error.
- Oil of lemonCold-pressed lemon peel oil, sold today as food-grade lemon essential oil. It is not lemon extract, which is the oil already cut with alcohol and much weaker; substituting extract volume for volume will give almost no flavour.
- The trituration is the pointRubbing the oil into the powdered citric acid before any bulk syrup goes in is what disperses it. Oil dropped straight into two pints of syrup will float and streak. Grind the acid fine first, work the oil through it, then let it down with an ounce or two of syrup before adding the rest slowly.
- The simple syrup is heavier than modern stockSeven and a half pounds of sugar to a finished gallon is roughly 900 g per litre — closer to a saturated syrup than the 1:1 most bars keep. Ordinary 1:1 syrup will give a thinner, sharper result; expect to adjust.
- Yield and useAbout two pints of finished syrup. Fountain measures of the period were commonly around one to one and a half fluid ounces per glass, topped with carbonated water, which would put this at roughly 20 to 30 drinks.
- The charging pressures are not a home operationFifty to seventy-five pounds of gas into an assembled fountain assumes a commercial pressure vessel and fittings maintained for the purpose. Carbonate the finished drink with modern equipment instead.
Soda fountains in America grew out of pharmacies, and this formula reads like it: apothecary weights, a mortar, and a working assumption that the operator keeps citric acid and volatile oils on the shelf. Citric acid syrup was a fountain staple — cheaper and more stable than fresh lemon juice, which kept poorly behind a counter and varied with the season. Dispensers used it both as a lemon flavour in its own right and as an acid backbone under fruit syrups that needed sharpening. The closing recommendation of "American Concentrated Syrups" points to a shift in the trade: books like this one still taught compounding from raw materials, while manufacturers were already selling finished concentrates that needed nothing but dilution. The ten-cent price and the specified "mineral water tumblers" are a reminder that the recipe was written for a business, not a household.