Ingredient
Measure
White rum (a light, clean style)
60 ml (2 oz)
Fresh lime juice
20 ml (⅔ oz)
Sugar syrup, 2:1 (rich)
10 ml (⅓ oz)
The 6:2:1 spec. The IBA lists 60 ml rum, 20 ml lime juice and two bar spoons of superfine sugar, which is the same sweetness as 10 ml of rich syrup.