Boston Sour

If you want foam that lasts, yes. Shake everything without ice for about ten seconds to whip the egg white, then add ice and shake again to chill and dilute. Done the other way round you get a thin bubbly layer that collapses before you have finished the drink.

The risk is low but not zero, and the usual advice applies: fine for most people, not for anyone pregnant, elderly or immunocompromised. Pasteurized whites from a carton behave identically and remove the question entirely. Fresh eggs whip marginally better, which is the only real argument for them.

It does, though not quite as firmly. Twenty-two milliliters of chickpea liquid whips to a similar head and tastes of nothing once the lemon and bourbon are in, but it collapses a few minutes sooner. Dry shake it a little longer than you would an egg to compensate.

Different addition entirely. A New York Sour floats red wine over a whiskey sour for a dark layer and a tannic edge. This one adds egg white for texture instead. Nothing stops you doing both, and the wine actually sits rather well on top of the foam.

Egg white is close to odorless but not quite, and a thick cap of it sits directly under your nose. Three drops of Angostura on the foam is the standard fix and it works. A wide lemon twist expressed over the surface does the same job without adding bitters.

A classic Boston Sour calls for 60 ml (2 oz) Bourbon, 22 ml (0.75 oz) Fresh lemon juice, 15 ml (0.5 oz) Simple syrup, 1 egg white Egg white. That single-serve spec scales cleanly — the recipe above converts it to oz and multiplies it for 2–4 drinks.

A standard Boston Sour is roughly 28% ABV once mixed (before ice melt softens it further). That makes it spirit-forward — closer to a Martini than to a beer, so sip it slowly.