What makes a gin a gin? Juniper, botanicals and the main styles, with a picker

Pour a gin and tonic and you can smell it before you taste it: a green, resinous, slightly piney note. That is juniper, and it is the one thing the law says every gin must have. Everything else, from citrus peel to coriander seed to cucumber, is up to the distiller. That is why two gins can taste nothing alike and still share a label.

What the label has to say

In the EU and the UK, a spirit can only be sold as gin if it is at least 37.5% ABV and tastes predominantly of juniper. There are three legal tiers, and the words on the bottle tell you which one you have:

• Gin is neutral alcohol flavoured with juniper and other flavourings. The flavourings can simply be mixed in, which is often called compound gin.
• Distilled gin is made by redistilling neutral alcohol with juniper and other natural botanicals, so the flavour travels over in the vapour. Flavourings may be added afterwards.
• London gin (also sold as London dry) is a stricter form of distilled gin. All the flavour must come from the distillation, nothing flavouring may be added afterwards, it cannot be coloured, and any sweetening is capped at a tiny 0.1 g per litre. The word "London" describes a method, not a place: it can be made anywhere.

So "dry" on a London gin does not mean strong or bitter. It means almost no sugar. Rules differ outside Europe, so treat this as the European picture.

Where the flavour comes from

A distiller picks a handful of botanicals, often between six and a dozen, and each one pulls the gin in a direction. Juniper brings pine and resin. Citrus peel (lemon, orange, grapefruit) brings brightness. Coriander seed is a quiet backbone with a lemony, peppery warmth. Angelica root and orris root are the quiet ones: they are earthy and dry, and they help the other flavours hold together. Then there is a long tail of extras such as cardamom, cassia, liquorice, rose, cucumber or lavender.

Two gins with the same botanical list can still differ, because the amounts, the still and the way the botanicals are steeped or vapour-infused all change what lands in the glass.

The main styles, in plain words

These are broad families, not strict rules, and individual bottles sit between them.

• London dry: crisp, juniper-led, little or no sweetness. The classic base for a Martini or a G&T.
• Plymouth: a softer, rounder, slightly earthy gin. Plymouth is also a protected name tied to the English city, so it is a place as well as a style.
• Old Tom: traditionally a little sweeter, a bridge between older sweet gins and the dry style. Handy where you want body without adding syrup.
• Contemporary (sometimes called new western): juniper still has to lead legally, but the distiller turns up something else, such as citrus, flowers or herbs.
• Genever: the Dutch and Belgian ancestor. It is made with a malted grain spirit, so it tastes maltier, closer to a light whisky, and it is usually sipped or used in older cocktails.

Flavoured gins and sloe gin sit on the edge. Sloe gin is a liqueur, with fruit and sugar added, and is bottled at a lower strength than a dry gin.

A quick rule of thumb

If you want one bottle for most things, a London dry covers the G&T, the Martini and the Negroni, because its juniper stays clear through tonic, vermouth and bitter liqueur. If you mostly drink long drinks and find pine sharp, a contemporary or Plymouth style is kinder. If you like to sip gin cold on its own, a softer style or genever will be easier going.

Break the rule when the drink changes the job. A Gimlet asks for citrus lift, so a bright, citrus-leaning gin shines there. A Negroni is robust enough to carry a juniper-heavy gin without it vanishing.

How to read a label

Look for "distilled gin" or "London gin" rather than just "gin" if you care about how it was made. Check the strength: most sit between 37.5% and 47%, and the stronger ones keep their flavour better when poured over ice. A colour or a flavour name (rhubarb, pink, spiced) usually means flavourings or sweetening were added after distilling, so it will not be a London dry.

Low and no versions

Gin without the alcohol is a growing shelf of its own. Alcohol-free "gin-style" spirits are not legally gin, since they miss the minimum strength, but many are built around juniper and citrus and do well with tonic. For a quick alcohol-free serve, build a tall glass with ice, an alcohol-free juniper-led spirit, a good tonic and a strip of lemon or grapefruit peel.

As always: enjoy gin in sensible measures, never mix it with driving, and keep it away from anyone under 18.