Here it is! The most famous secret recipe in the world.
1. Mix 2,400 grams of sugar with just enough water to dissolve (high-fructose corn syrup may be substituted for half the sugar).
2. Add 37 grams of caramel, 3.1 grams of caffeine, and 11 grams of phosphoric acid.
3. Extract the cocaine from 1.1 grams of coca leaf (Truxillo growth of coca preferred) with toluol; dry the cocaine extract.
4. Soak the coca leaves and kola nuts (both finely powdered; 0.37 gram of kola nuts) in 22 grams of 20 percent alcohol.
5. California white wine fortified to 20 percent strength was used as the soaking solution circa 1909, but Coca-Cola may have switched to a simple water/alcohol mixture.
6. After soaking, discard the coca and kola and add the liquid to the syrup.
7. Add 30 grams of lime juice (a former ingredient, evidently, that Coca-Cola now denies) or a substitute such as a water solution of citric acid and sodium citrate at lime-juice strength.
8. Mix together 0.88 gram of lemon oil, 0.47 gram of orange oil, 0.20 gram of cassia (Chinese cinnamon) oil. 0.07 gram of nutmeg oil, and, if desired, traces of coriander, lavender, and neroli oils, and add to 4.9 grams of 95 percent alcohol.
10. Add 2.7 grams of water to the alcohol/oil mixture and let stand for twenty-four hours at about 60 °F (15.5 °C). A cloudy layer will separate.
11. Take off the clear part of the liquid only and add the syrup.
12. Add 19 grams of glycerine (from vegetable source, not hog fat, so the drink can be sold to Jews and Muslims who observe their respective religion’s dietary restrictions) and 1.5 grams of vanilla extract.
13. Add water (treated with chlorine) to make 1 gallon of syrup.
This recipe is from Food Flavorings: Composition, Manufacture and Use (2nd Ed.) 1968 by Joseph Merory (AVI Publishing Company, Inc., Westport, CT). Makes one U.S. gallon (3.8 L) of syrup. Yield (used to flavor carbonated water at 1 fl oz per bottle): 128 bottles, 6.5 fl oz (192 ml).