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Simple Syrup by Percolation - Cold Process
Sugar, 12 lbs.; Water, 1 gallon.
Put sugar into a large percolator, first putting some cotton in bottom of percolator so that sugar cannot run through (or barrel arranged as a perco lator, by means of a perforated false bottom supported above the spigot). Add water, and let it drop slowly from bottom of percolator. When water has all run through it will have dissolved the sugar, and the syrup will be made. This process has the advantage of being automatic, the syrup making itself without work on the part of the dispenser.
A druggist's method for making stock syrup without heat, borrowed straight from the pharmacy bench. The chemistry is sound, but a cold-made syrup behaves differently in storage than a boiled one.
- The ratio, scaled down12 lb sugar to 1 gallon of water is about 1.44 parts sugar to 1 part water by weight. For a home batch, use 1 lb granulated sugar (roughly 2 1/4 cups) to 11 fl oz of water and expect about 1 1/4 pints of finished syrup.
- What a percolator meant hereNot a coffee pot. A pharmacist's percolator is a tall cone or cylinder, open at the top, with a narrow outlet and a stopcock at the bottom; liquid is allowed to seep down through a packed column. Any tall vessel that can be plugged at the base and drained slowly will do.
- Cotton, not filter paperThe cotton wad is a plug, not a filter. It has to hold back the sugar column while letting a heavy syrup pass, so it should be packed firm but not compressed into a dam. Rinse it first; unwashed cotton can carry lint and a papery taste into the syrup.
- Slowly is the whole instructionThe water must trickle. If it runs freely it channels through the sugar bed and comes out the bottom as weak syrup with dry sugar still sitting above it. Aim for a thin thread or a fast drip, and if the first run-through is thin, pour it back over the top and let it pass again.
- YieldClose to 1 7/8 gallons of syrup from the quantities given, since the dissolved sugar contributes its own volume. At this strength the syrup measures somewhere around 32 degrees Baume on a hydrometer.
- Why cold, and what it costsNo heat means no caramel note, no scorching, and no inversion of the sucrose, so the syrup stays neutral and takes flavoring cleanly. It also means nothing is pasteurized. Cold-process syrup molds and ferments sooner than boiled; keep it refrigerated and use it within a couple of weeks, or expect a cloudy surface bloom.
- Undissolved sugar at the endThe recipe expects the water to dissolve all the sugar, and at this ratio the finished syrup is below saturation, so it should. If the run was too fast you may still find damp sugar in the column; do not force more water through to chase it or the batch will finish weak. Save the residue for the next run.
Percolation was a pharmacist's technique before it was a soda fountain one. The United States Pharmacopoeia specified percolation for extracting drugs from vegetable material with alcohol or water, and where the apparatus was already at hand, turning it to sugar was an obvious economy for the dispenser who also ran the fountain, which in America was very often the same man. The appeal, as the text says plainly, is that it is automatic: a boiled syrup demands watching, skimming and cooling, while a percolator can be charged in the morning and left to drip through while the counter is busy. The result is a colorless, uncooked stock syrup that could be flavored into a dozen different sodas, which is exactly what a fountain needed. The trade-off, understood at the time in terms of keeping rather than of microbiology, was that cold syrup would not stand as long as boiled.