The drinker | gin

When you taste six gin brands side-by-side - the sort of thing we diligent drinks writers sometimes have to do - you see a quality range roughly equalling the distance between Britney Spears and Beethoven. Never mind that all gin is made the same way: flavouring neutral alcohol with aromatic ingredients ("botanicals"), of which juniper must by law be the greatest in volume and coriander seed is secondary but essential. The devil's in the details. Some producers use more juniper, some less. Ditto for the other aromatics - angelica, orange peel, lemon or lime peel, cardamom among others. And methods of adding the aromatics vary.

When you taste six gin brands side-by-side - the sort of thing we diligent drinks writers sometimes have to do - you see a quality range roughly equalling the distance between Britney Spears and Beethoven. Never mind that all gin is made the same way: flavouring neutral alcohol with aromatic ingredients ("botanicals"), of which juniper must by law be the greatest in volume and coriander seed is secondary but essential. The devil's in the details. Some producers use more juniper, some less. Ditto for the other aromatics - angelica, orange peel, lemon or lime peel, cardamom among others. And methods of adding the aromatics vary.

My most recent foray into serious gin tasting took place at the new Soshomatch bar in London, under the technical guidance of Sean Harrison.

Sean is chief distiller for Plymouth Gin, a brand that has gone from strength to strength recently. He describes gin as a drink that "takes the most neutral alcohol and ties its flavours to it". But not all neutral alcohols are created equal. While the type distilled from molasses is cheapest, Plymouth (like others) uses grain alcohol because it "adds a little bit of magic that we want". And while Sean says they make their gin as close as possible to the original ("gin is 95 per cent recipe"), it's better now "because the alcohol is better". The aim: a full, balanced style in which all the botanicals are apparent but none is allowed to dominate.

So much for theory; our glasses were filled and we got down to work. Gin tasters taste at room temperature, which is not fun, but the process revealed remarkable differences, especially in two clear losers. Bombay Sapphire, that marketing triumph, had assertive orange on the nose but was harsh and thin on the palate. Gordon's lacked fullness of flavour; it was unpleasantly heavy with juniper, and had a harsh finish.

And then: three winners. Tanqueray hit hard on the palate, with more pronounced spice flavours; a good overall gin. Beefeater was better rounded, with a nice sharp edge of astringency carrying through to the finish. Plymouth was smooth and perhaps the fullest in flavour, although I thought Plymouth Navy Strength (57 per cent ABV) had alcohol out of balance. But what do I know? It has just won the white spirit trophy in the International Wine and Spirit Competition.

After tasting neat we went on to cocktails mixed by Dick Bradsell, Soshomatch's cocktail consultant, and found that other ingredients accentuate differences. With standard Martinis, the quality of the gin was laid stark naked. Plymouth, Beefeater and Tanqueray all showed well, as expected. Bombay and Gordon's - don't even think about it.

The real surprise came in more complicated cocktails. In a Tom Collins - lemon, sugar, gin, topped with soda - Beefeater was sharp and thin. In a Ramos Gin Fizz - gin, lemon juice, orange bitters, maraschino liqueur, curaçao, egg white, cream - Bombay, which contains almonds, was like liquid marzipan. In a Sour - basically a Collins without the soda - Tanqueray was too tart. In a Cowboy Martini (basically a Mint Martini), Bombay accentuated unpleasantly the bitterness in the mint.

If you think tastings like this take tippling into the realms of pedantry, you're wrong. The point is that you can choose, in a good bar, which to order. Make that choice. Not for the sake of pedantry, but for your own enjoyment. Which is why people drink cocktails in the first place.