Intoxicated by plants: the links between botany and alcohol

The inspiration for the following intemperance came from a chance encounter with Scott Calhoun, an agave and cactus expert from Tucson, at a convention of garden writers in Portland, Oregon.

He had been given a bottle of Aviation, a fine locally made gin and he didn’t know what to do with it. But I did. We went in search of fresh jalapeños, some coriander and a few cherry tomatoes.

As we searched we realised that gin itself is a hymn to botany: Juniper, a conifer. All gins contain citrus peel. This one has lavender buds, too. In the liquor store the realisation went further: all around us were bottles ... of horticulture.

I hunted for the ingredient I needed – proper tonic water, made with cinchona bark and real Saccharum officinarum, not that artificial junk – while Scott browsed the selection of bottled Agave tequilana. He was in the habit of trekking into Mexico in search of rare agave and cactus, and he had encountered many of his prized specimens coming out of the working end of a handmade Oaxacan still.

Before we left, we stood in the doorway for a minute and looked around us. There wasn’t a bottle in the store that we couldn’t assign a genus and species to. Bourbon? Zea mays, an overgrown grass. Absinthe? Artemisia absinthium, a much misunderstood Mediterranean herb. Polish vodka? Solanum tuberosum – a nightshade, which is a weird family of plants if there ever was one. Beer? Humulus lupulus, a sticky climbing vine that happens to be a close cousin to cannabis. Suddenly, we weren’t in a liquor store any more. We were in a fantastical greenhouse, the world’s most exotic botanical garden, the sort of strange and overgrown conservatory we only encounter in our dreams.

Just about any non-poisonous plant can, with the help of yeast, be transformed into molecules of intoxicating ethyl alcohol. But that is only the beginning. A great gin or a fine French liqueur is flavoured with innumerable herbs, seeds, and fruit, some of them added during distillation and some just before bottling.

And once a bottle gets to the bar, a third round of plants are called into service: mixers like mint, lemon, and – if the party’s at my house – fresh jalapeño.

Drinks and mixers at the ready

Oak Quercus

Nothing tames a rough spirit like an oak tree. The practice of ageing whiskey or wine in a barrel might have started as a practical solution to a storage problem, but it was soon obvious that something wonderful happened when alcohol came in contact with wood – and oak in particular.

Oak trees have been around for about 60 million years. They emerged as a distinct genus not long after the mass extinction of dinosaurs. Taxonomists disagree about the exact number of species; depending on who you ask, the number ranges from 67 to 600. However, we are only concerned with the handful of American, European, and Japanese species used by barrel makers for wine and spirits.

Wooden barrels have been in use for at least 4,000 years, judging from archeological evidence, and oak was probably the natural choice from the beginning. The wood is hard, dense, but still pliable enough to bend into a slight curve.

The trees also happen to produce an astonishing array of flavour compounds that break free from the wood in the presence of alcohol. European oak, Quercus robur in particular, is high in tannins, which give wine a certain roundness and full-bodied quality. American white oak, on the other hand, releases the same flavour molecules found in vanilla, coconut, peach, apricot, and cloves. (In fact, artificial vanilla is made from a sawdust derivative because it has such high levels of vanillin.) Those sweet flavours might not be what a winemaker is looking for, but they are pure magic in bourbon.

Perhaps the most important influence on oak-aged spirits comes not from the tree but from the barrel makers, called coopers. They learnt that coaxing oak staves into gentle curves required two things: time and heat. Freshly cut oak is given time to dry, which not only makes it easier to work with but also concentrates those important flavours. The staves are also lightly cooked to make them more pliable as they are shaped, and fire causes some of those flavours to caramelise, so that caramel, butterscotch, almond, toast, and warm, woodsy, smoke essences emerge.

A field guide to oak

Q. alba – American white oak; grown in the eastern US, used for whiskey and wine.

Q. garryana – Oregon oak, used by some Pacific Northwest wineries and distillers. Comparable to French oak.

Q. mongolica – Japanese oak, popular among Japanese distillers.

Q. petraea – Sessile or French oak; commonly grown in Vosges and Allier. Preferred by winemakers.

Q. pyrenaica – Pyrenean oak, often used for port, Madeira, and sherry.

Q. robur – European oak; commonly grown in Limousin. Preferred for Cognac and Armagnac.

Pomegranate Punica granatum

Cocktails, tried and tested

An 1867 medical journal entry on pomegranate explains that “the tincture, a liqueur glass morning and evening, infallibly expels the yellow tapeworm”. This was not the first report of the vermifugal powers of pomegranate: a Portuguese doctor had been making a tea of the bark for the same purpose since 1820 which he called grenadine.

A pomegranate tree is a large shrub of Asian and Middle Eastern origin. It still grows wild there today, but now it is cultivated throughout Europe, the Americas and in tropical areas around the world. Although the tree has ancient origins and was extensively grown by Egyptians, there are just two species. The plants were once classified in a taxonomic family by themselves, until new molecular research uncovered their close genetic relationship to purple loosestrife, crepe myrtle, cuphea, and other seemingly dissimilar plants. (Crumpled flower petals are their most obvious shared anatomical feature.)

Pomegranate trees are now grown primarily in the Middle East, India, and China, although they are a speciality crop in the Mediterranean, and in Mexico and California. The fruit earned its species name, granatum, from the Latin word for “seeded,” and its fruit does, in fact, contain a few hundred seeds surrounded by bright red pulp. The syrup made from it, grenadine, derives from the early French word for pomegranate – grenade. The hand-thrown projectile of the same name was invented in the 16th century and was named after the fruit, perhaps because they were each the same size and filled with explosive materials of a very different kind.

Grenadine is an essential ingredient in hundreds of cocktails, including the Jack Rose and the tiki classic, Tequila Sunrise. But there is no substitute for homemade grenadine made from fresh-squeezed pomegranates. Even replacing the fresh juice with bottled compromises the flavour. When the fruit is in season, it is well worth spending an hour or so in the kitchen making up a batch for the freezer.

Edited extract from ‘The Drunken Botanist: The Plants that Create the World’s Great Drinks’, by Amy Stewart, published by Timber Press


How to make fresh grenadine

Grenadine

5 to 6 fresh pomegranates

250g sugar

30ml vodka

To peel the pomegranates, score the rind with a knife as if you’re cutting an orange into wedges. Carefully peel away the rind, leaving the seeds and membrane intact. Squeeze with a fruit press or manual juicer and filter through a sieve. You should have about 2 cups of juice.

Put the sugar into a saucepan, add the juice, stir, and bring to a simmer. Let the syrup cool and taste it; add more sugar if you prefer a sweeter syrup. Stir in the vodka as a preservative. Pour into a clean jar and store it in the refrigerator, where it will last about a month, or in the freezer. Adding another 30ml to 50ml of vodka will help keep it from freezing.

Jack Rose

45ml applejack, or apple brandy

15ml fresh lemon juice

15ml grenadine

Shake all the ingredients over ice and strain into a cocktail glass.


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