How to cost a cocktail
Cost each ingredient by the millilitre, add them up, then compare the total with the ex-VAT menu price.
Ingredient cost = bottle price ÷ bottle size (ml) × pour (ml)
GP = (menu price ÷ 1.2 − cocktail cost) ÷ (menu price ÷ 1.2)
Example: a Margarita with 50ml tequila (£24.00 per 70cl), 25ml orange liqueur (£18.00 per 70cl), 25ml lime juice (£6.00 per litre), 10ml agave syrup (£8.00 per 75cl) and £0.15 of garnish costs £2.76. At a £12.00 menu price, that's £10.00 ex VAT and a 72.4% GP, or £7.24 cash GP per drink.
GP % or cash GP?
GP % tells you how efficient a drink is. Cash GP is what pays the bills. A premium cocktail at 70% GP can earn more per glass than a cheap one at 80%, so look at both.
Blended GP across a menu
Your menu GP is not the average of each drink's GP. It's total cash GP divided by total ex-VAT sales, so best sellers count for more. If your top seller sits below target, fixing its price or spec moves the whole menu more than tweaking a slow seller.
Wastage
Over-pours, spillage and spoiled fresh juice all add cost. A wastage allowance of a few percent keeps the costing honest.