Important: Safety Warning
This page describes trade processes that use dangerously toxic materials such as cyanide solutions, mercury amalgams, or strong acids. These processes require training, equipment, and precautions far beyond what the text describes.
This information has been left in for historical purposes but should not be acted upon.
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Raspberry Vinegar
Raspberry Syrup, 1 gallon; Glacial Acetic Acid, 1 ounce.
This is a soda fountain dispensing formula rather than a kitchen recipe: it produces a bottled syrup to be drawn off by the ounce and finished with carbonated water. It cannot be made as printed, because the acid it calls for is not a food ingredient in the form specified.
- Glacial acetic acid is not vinegarGlacial acetic acid is acetic acid at roughly 99 percent strength. It is corrosive to skin, eyes and the lining of the nose and throat, and its vapour is harmful in a closed room. Vinegar is the same acid at 4 to 6 percent; the two are not interchangeable in handling terms, however similar the chemistry.
- No dilution or handling procedure is givenThe formula states two quantities and nothing else. It does not say to add the acid to the syrup rather than the reverse, does not call for eye protection or ventilation, and does not specify how the acid is to be measured out. Those omissions are the whole of the danger.
- Grade is unspecifiedAcetic acid is sold in reagent and technical grades that are not certified for consumption and may carry metal or solvent impurities from manufacture. A period druggist's stock bottle offers no assurance a modern reader can rely on.
- The ounce is ambiguousFormulary and fountain books of this period are not consistent in using "ounce" for fluid measure or for weight, and the page gives no indication which was meant here.
- What the finished syrup was forA gallon of fountain syrup was drawn at about one to one and a half fluid ounces per glass, so this batch was intended to serve on the order of a hundred drinks — a trade quantity, not a household one.
- If you want the drinkThe flavour being aimed at is a raspberry shrub, and a current recipe using ordinary bottled vinegar should be used instead.
Raspberry vinegar, or raspberry shrub, long predates the soda fountain: fruit steeped in cider or wine vinegar, strained, and sweetened into a syrup that kept through the winter and was let down with cold water as a summer drink or given to the sick as a throat soother. It was a common summer preparation in nineteenth-century American households, and the tartness was the point — the acid cut the sugar and made the raspberry taste sharper than fruit alone. When the drink migrated to the marble counter, the fountain trade rebuilt it from stock: instead of macerating berries in vinegar for a week, the dispenser took the raspberry syrup already on the shelf and added acid directly. Formula books of this kind contain many such shortcuts, and they reflect the fact that the soda fountain of the era sat somewhere between a lunch counter and a dispensary, with the druggist's stock bottles within arm's reach of the glasses.