Orange Phosphate

This is a fountain formula rather than a single drink: it tells the dispenser how to batch the syrup, then how each glass is finished to order. The carbonated water is assumed, which is why it goes unmentioned.

• What is missingNothing here says to add soda water, because at a fountain that was the given. Draw 1 to 1.5 oz of the flavored syrup into the glass, then fill with cold carbonated water, coarse stream first and fine stream to finish.
• Acid phosphateA dilute solution of phosphoric acid with calcium, magnesium and potassium salts, sold specifically for fountain use and still made today. It gives a dry, mineral sourness quite unlike citrus, and it is what makes a phosphate a phosphate rather than a plain orange soda. A "few squirts" from the counter dispenser is roughly a quarter to a half teaspoon per glass.
• Orange phosphate extractA commercial concentrated flavoring, not orange juice. Modern equivalents are orange oil-based soda extracts; failing that, use about 2 tsp of good orange extract plus the zest of two oranges steeped in the syrup, and expect a softer result than the original.
• Simple syrupFountain simple syrup was heavier than the bar standard: roughly 2 parts sugar to 1 part water by weight, near saturation, so that a small pour carried the whole glass. A 1:1 syrup will taste thin at these proportions.
• YieldA gallon of syrup plus a pint of extract gives about 144 oz, or roughly 95 to 145 drinks at 1 to 1.5 oz each. Scale down hard for home use: 1 cup syrup to 2 tbsp extract keeps the recipe's own 1:8 proportion.
• The glass"Small, thin tumblers" means 6 to 8 oz with thin walls, which keep the drink cold-feeling and let the carbonation show. Chill the glasses and the soda water; warm water holds far less gas and the phosphate goes flat and flabby.
• Keeping the syrupSugar at fountain strength is largely self-preserving, but a batch this size will still pick up mold at the neck of the bottle. Refrigerate and use within a month, or make a fraction of the quantity.