You don’t need to be a master mixologist to rustle up one of these classic cocktails.

Amazingly, each of the 20,000 or so genes that make up every single human being is made of just four simple amino acids. So, everything from eye colour to the size of your feet is dictated by a biochemical cocktail. Too much of this and you get a Donald Trump, too little and you get a Hillary Clinton. It’s all about balance.

Fortunately, when it comes to our drinking DNA, we have complete control. With just four simple spirits — gin, bourbon, vermouth and Campari — you can create an almost infinite variety of cocktails, a genome of joy. Cocktailing — yes, it’s a verb and F Scott Fitzgerald first used it, so take it up with him — is not as complicated as you might fear.

Of all skills, “learning how to make strong, effective cocktails is the least likely to be a waste of your time,” says Richard Godwin in The Spirits, his excellent guide to mixing drinks at home. “It’s not hard. Serving 500 perfect drinks to exacting patrons in a bar is hard. Serving four negronis to guests before dinner is easier than making toast.”

Aim for fine but not fiddly. Even I sag at the thought of having to source Arctic ice cubes or lay my hands on a tincture of Aslan’s Tears. I’m all for adventure, and no bar is more eccentric than Ryan Chetiyawardana’s White Lyan, but I’d rather sit down there and have him make me a refreshing, vegetal garden buck than labour over my own sugarsnap and asparagus syrup.

All the bartenders I know like simple drinks. So to impress the staff, order a boulevardier (1). Erik Lorincz, head bartender at the American Bar in the Savoy, loves a manhattan and has his own special barrel behind the bar (2). If you want something stiffer and lighter, mix a gin and it (3).

Just don’t skimp on ice or forget the Angostura bitters: it’s like cooking without seasoning. To make your cocktail sweeter, bitter or more aromatic, just tweak the DNA.

All recipes from The Spirits by Richard Godwin (Vintage £17)

What you should be drinking this week

Boulevardier
A classic variation on the negroni with bourbon instead of gin.

INGREDIENTS

  • 25ml Wild Turkey bourbon (£23, Tesco)
  • 25ml Punt e Mesvermouth (£13, Tanner’s Wines)
  • 25ml Campari (£15, Asda)

Stir over ice then serve in an old fashioned glass with fresh ice and a slice of orange.

Manhattan
You can have this dry, sweet or perfect.

INGREDIENTS

  • 50ml Buffalo Trace bourbon (£23, Tesco)
  • 20ml Cocchi Vermouth di Torino (£20.45, the Whisky Exchange)
  • Dash Angostura bitters

Shaking makes it watery, so just stir over ice. Serve, with or without ice, in a chilled glass with a cherry or orange zest twist.

Gin and It
The “It” stands for Italian vermouth.

INGREDIENTS

  • 50ml Sipsmith London Dry gin (£29.50, 31dover.com)
  • 25ml Carpano Antica vermouth (£14, Waitrose)
  • Dash Angostura bitters

Stir over ice and serve in an old fashioned glass with no ice and a lemon zest twist.