1Half fill a shaker with shaved ice and add the syrup, lemon juice and gin.
2Shake well and strain into a large glass.
3Fill with soda water and drink it while it fizzes.
Variations: Today it is served over ice, usually with more sugar: Difford’s shakes 50 ml Old Tom gin, 20 ml lemon and 15 ml rich syrup and tops it with 50 ml soda. Made with London dry gin it is often called a John Collins.
Thomas gives a large wineglass of spirit and the juice of a small lemon; the numbers take the wineglass as 2 oz and the lemon as 1 oz. The soda isn’t measured; the numbers assume 2 oz. His recipe is written for whiskey, with brandy and gin versions; he doesn’t say which gin, and he serves it without ice.
The ratio
1 : 2 : 2
In parts, a Tom Collins is 1 lemon, 2 gin and 2 soda. Plus a touch of syrup. Change one part and you have a cousin; the closest are below.