
Sugar syrup is sugar dissolved in water, the standard liquid sweetener in cocktails. Measures assume the rich 2:1 kind: two parts sugar to one part water by weight.
The default sweetener, used instead of sugar because it is already dissolved: crystals never fully go in a cold drink. About 8 ml rounds a drink off and 15 ml sweetens it outright. A long or very sour drink can take up to about 45 ml.
Make it yourself
It is easy to make at home: mix two parts sugar with one part warm water by weight. Heat gently, stirring until fully dissolved. There is no need to boil.
Gum syrup
Use the same amount. The sweetness of the drink stays, but its texture turns noticeably fuller and silkier.
If it is made at the classic bar ratio (2:1), use the same amount. It keeps the balance and adds light notes of cane molasses and caramel.
Simple syrup (1:1)
Plain thin syrup is less concentrated. To balance a drink built on rich 2:1 syrup, you will need about half as much again.
Honey or agave syrup
These sweeteners differ in sweetness and have a strong flavor of their own. Add them carefully, a little at a time, tasting the drink each time.
Refrigerated in a clean bottle, 2:1 syrup keeps about six months and a 1:1 syrup about a month. The richer one has less water to spoil. A spoon of vodka extends either. Threads, cloudiness or a fizz mean it has gone, and there is no rescuing a syrup.
Dry Espresso Martini
Bourbon