Fernet cocktails.

Fernet is the hardest-edged branch of the amaro family — intensely bitter, minty and medicinal, bottled at nearly spirit strength, and drunk neat by bartenders as a kind of professional handshake. In Argentina it is mixed with cola by the million litres. In a cocktail it is used in dashes, and the drinks that use it well are few, old and very good.

What is fernet?

An Italian style of bitter liqueur, not a brand: any producer can make a fernet, and several do. The defining example was created in Milan in 1845 by Bernardino Branca and is still made by his family's company, and its recipe — myrrh, saffron, chamomile, gentian, aloe, rhubarb, bitter orange, cinchona and, famously, a great deal of mint among around 27 herbs — sets the template. Fernets are drier and more bitter than other amari, use little sugar, and are bottled strong: 39 to 45% ABV against the 16 to 30% of most of the family.

It was sold as a medicine first — for cholera, for digestion, for whatever ailed you — and the name may come from a Dr Fernet who supposedly contributed the recipe, or from the dialect for the iron bar used to stir it. Nobody is sure, and the company enjoys the ambiguity.

How it's made

The herbs, roots, barks and spices are macerated separately or in groups in neutral spirit — the Milanese original says 27 ingredients from four continents, with the saffron alone accounting for a significant share of the world's supply — then blended, lightly sweetened and aged. The flagship rests in large Slavonian oak vats for a year before bottling. Other fernets use their own herb lists and shorter ageing, but the formula is always the same: a lot of bitter, a lot of mint, not much sugar.

What it tastes like

Peppermint and eucalyptus up front, then a dense, dark bitterness — gentian, cinchona, myrrh — with saffron, liquorice, bitter orange and something like old wood and camphor behind. The finish is long, cooling and bone-dry. The first sip is a shock; by the third it is a taste you have, or do not. The mint-forward sub-style is sweeter and simpler; a few artisan fernets are gentler and more herbal.

Styles worth knowing

Style	What changes	In a drink
Milanese fernet (39%)	The benchmark; intensely bitter and minty	Toronto, Hanky Panky, Fernet and Coke, a dash in a Manhattan
Fernet menta	Sweeter, mint-dominant, lower proof	Over ice; a digestif
Other Italian fernets	Vary from close to much gentler	The same drinks; adjust the dose
American craft fernets	Often more herbal, less mint, sometimes aged	Stirred drinks; sipping
Argentine fernet	Made locally for the cola market; very similar	Fernet con coca

Which bottle to buy

Start with the Milanese original. It is the one every recipe means and the one your bartender is drinking. A bottle lasts for months at a dash per drink, or a week if you take to drinking it neat. The menta version is a different, softer thing and not a substitute in cocktails. Craft fernets are worth exploring once you know what the benchmark tastes like.

Using it in drinks

Two famous drinks lead with it. The Toronto stirs a quarter-ounce with rye, sugar and bitters, and is the proof that fernet and whiskey belong together; the Hanky Panky — gin, sweet vermouth and two dashes of fernet, created by Ada Coleman at the Savoy around 1925 — is the gin version. Fernet and Coke, fernet con coca, is Argentina's national mixed drink, roughly one part fernet to two or three of cola over ice, and it is far better than it sounds.

Beyond that: a dash in a Manhattan or an Old Fashioned adds a cooling bitter edge, and a bar-spoon in a Mint Julep is a known trick. Neat, after dinner, at room temperature or over a single cube, is the traditional use and the one bartenders mean by the handshake.

Substitutes

Nothing is close. Another fernet is the only true swap. For a dash in a stirred drink, a strong amaro such as a rabarbaro or an alpine amaro gives bitterness without the mint; a few drops of crème de menthe alongside restores some of it. Angostura bitters in larger-than-usual quantity is the emergency fallback. Do not try to replace it with Jägermeister; the sweetness is wrong.

Storage

Room temperature, upright, out of the light — it is nearly spirit strength and does not spoil. Argentines keep it in the freezer for cola; bartenders keep it on the back bar. Either is fine.

Questions

Why do bartenders drink fernet? Partly habit — San Francisco bartenders adopted it in the 1990s as an industry drink — and partly because it is bitter enough to reset a palate and strong enough to be a proper shot. The "bartender's handshake" is a shot of fernet offered to a colleague.

Is fernet good for digestion? It was sold as a digestive and the bitter herbs in it are the traditional ones. Whether it does anything beyond tasting like medicine is not established. It is not a cure for anything.

Why Argentina? Italian immigration. Argentina drinks more fernet than Italy, mostly as fernet con coca, and the Milanese company built a distillery in Buenos Aires to keep up.

Is it an amaro? Yes — the most bitter, least sweet, strongest corner of the family.