What the cocktail cost includes
Each ingredient cost is calculated from the proportion of its pack used, then the total is adjusted for a percentage of preparation loss.
Where costing usually goes wrong
Free-pouring, homemade syrups, batch dilution and citrus yield can all distort the result. Cost batches separately and enter the finished batch as an ingredient when the preparation is material. An unusually expensive extra can simply be added as another ingredient.
Batch recipes are deliberately absent here. Saving ingredient prices and reusable batches is recurring-work value reserved for the eventual paid margin book.