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Rock Candy Syrup
Sugar, 16 lbs.; Water, 1 gallon.
This will produce over 2 gallons of very heavy syrup. Put water and sugar in kettle, stir constantly until it boils up once; strain and set aside to cool. When it gets cold there will be a skim of crystalized sugar on the top; strain again to remove this skim, and you will have rock candy syrup, which is sugar syrup just below the crystalization point. You can reduce this with one-fifth of its bulk of water before using it to make fountain syrups. Beginners are advised to stick close to the popular and well established flavors-Vanilla, Chocolate, Lemon, Strawberry, Pineapple, Raspberry, Orange and Sarsaparilla.
This is the base stock of the old soda fountain: a saturated sugar syrup held just short of crystallizing, cut with water and flavored as needed. Nothing about it is difficult, but the whole point of the recipe is the saturation level, and that is where it goes wrong.
- The hinge: stop stirring once it boilsStir only until the sugar dissolves and the pot comes to a boil, then leave it alone. Agitating a near-saturated syrup, or scraping undissolved grains down from the sides of the pot, seeds crystallization and you get a pot of grainy sludge rather than clear syrup. Wipe the pan walls down with a wet brush instead.
- Scale it down16 lb sugar to 1 gallon water is a fountain-sized batch. That works out to 1 lb sugar to each cup (8 fl oz) of water, or roughly 2:1 sugar to water by weight. A tenth of the recipe — 1 lb 10 oz sugar to about 1 2/3 cups water — yields a little under a quart of heavy syrup.
- "Kettle"Here it means a large heavy-bottomed pot, not a tea kettle. Use something at least twice the volume of the finished syrup; a heavy sugar solution climbs the sides when it boils up.
- Why the skim formsWater at boiling will hold nearly five times its weight in sugar; at room temperature only about twice. Cooling therefore pushes the batch to exactly the edge of saturation, and the excess drops out as the crust the recipe tells you to strain off. That crust is the proof the syrup is right — do not stir it back in.
- StrainingLine a sieve with muslin or a coffee filter. Cold heavy syrup is slow and stubborn; give it time rather than pressing it through, which drags crystal fragments into the clear syrup.
- Reducing for use"One-fifth of its bulk of water" means 1 cup water to every 5 cups syrup. That lands in the region of 30 degrees Baume, the sort of density period fountain manuals treated as standard drink syrup. A cheap hydrometer or refractometer takes the guesswork out if you are matching a period formula.
- Yield and storageThe full batch gives a little over 2 gallons heavy syrup, about 2 1/2 gallons once reduced. The undiluted syrup is too sugary for most microbes and keeps for months in clean sealed bottles, but it will throw crystals if it gets cold or if a stray grain gets in; the reduced syrup should be refrigerated and used within a few weeks.
- The flavor listVanilla, lemon and orange are extracts or oils stirred into the reduced syrup to taste. Strawberry, raspberry and pineapple were fruit-juice or crushed-fruit syrups. Sarsaparilla and chocolate need their own separate preparations — this recipe supplies only the sweet base.
Rock candy syrup takes its name from its nearness to crystallizing: rock candy is made by hanging a string in a saturated sugar solution and letting the excess sugar crystallize onto it, and this syrup is that same solution stopped one step earlier. American soda fountains of the late nineteenth and early twentieth centuries commonly worked from a heavy stock syrup like this one, because it keeps without spoiling and can be cut and flavored on demand rather than made fresh each morning. The closing advice — stick to vanilla, chocolate, lemon, strawberry, pineapple, raspberry, orange and sarsaparilla — reflects the staples of the fountain trade, and a reminder that the soda fountain grew out of the pharmacy counter, where sarsaparilla carried associations as a tonic as well as a flavor.