For those who have never set eyes on a mature blue agave, let me give you a brief description. Unless you're a professional basketball player, it's probably as tall or a little taller than you. Blue, broadsword-sized leaves come soaring up out of its heart; not only are their tips needle-sharp, but there are fierce little darts all the way along the edges. Reversing into an agave can mean you don't sit down for a week.

Those who harvest this spectacular succulent (not a cactus, but a member of the lily family), slice away the leaves to reveal the plant's massive, fibrous heart. It looks like a pineapple on steroids, and is well beyond the lifting abilities of the ordinary flimsy human. These piñas loll about in the fields like the heads of giant, dismembered dolls before being trucked off to the Tequila factories. There the agave hearts are axed into quarters, then shoved into an oven for a day or two, before being pulped, fermented and then distilled. One look at a harvested agave, and you'll understand why the next generation won't replace it for eight or nine years. This is one mother of a fruit.

It's also why Tequila is in crisis. When I visited Carlos Camarena of Tapatio and El Tesoro last year, he told me that he was being inundated by requests from rivals to buy some of the fruit of his extensive agave fields. When there had been a glut five or six years ago and he'd offered competitors his surplus agave, the answer had been a dusty one. Now it was his turn to affect partial deafness.

Few spirits have taken off as vertically as Tequila over the last decade; production has doubled in the last five years alone. Not only that, but the popularity of pure-agave Tequilas has also ballooned (most basic Tequila is produced from 51% agave spirit and 49% other spirits, usually rum-like sugar-cane spirit). Production of pure-agave tequila rose fourfold between 1995 and 1999. The bad old days of bulk shipment of mediocre Tequila to the US where it disappeared into a million small-town margaritas seems to have finished.

As if this fashionability was not putting enough strain on supplies, there is also the threat of what the Mexicans are calling 'Tequila AIDS' - a blight which is damaging previously healthy agave plants before they reach full maturity. I have been told that this is actually a combination of damage from the erwinia bacterium and the fusarium virus; remedies have been found, but the difficulty consists of getting this armour-plated, camel-like semi-desert plant to swallow and metabolise its medicine. Some sources estimate that agave AIDS may be affecting up to 30% of the country's stock.

Wine traders with long memories will probably smile ruefully when they hear this story. Champagne, the Languedoc, Sicily, Germany, South Africa: the pendulum swings between undersupply and oversupply have dogged wine production for centuries, and continue to do so now. They have been planting furiously in Australia for the last five years to overcome shortages, and the word 'glut' (pronounced 'glat') is being heard in Adelaide bars today with surprising frequency. At least vines have the advantage of a four-year cycle from vineyard preparation to first harvest. The eight to 10 years it will take to sort out Mexico's agave shortage could have graver consequences altogether. Not only will many smaller producers go to the wall, but 'Tequilalike' products, called strange names like 'licor de agave', are beginning to appear on the market with less than 50% agave spirit. As pressure grows to alter the 51% rule, the threat to Tequila authenticity becomes acute.

It's no good cursing fate. Anyone who has tasted a range of top, pure-agave Tequilas will know that this drink genuinely has the potential to become the Cognac of Central America. Tradition, flavour, inimitability, image: it's got the lot. Tequila producers are going to need all the foresight they can lay their hands on over the next few years, since if they let standards slip during the crisis it will take a long time to claw them back.

One day, I predict, all Tequila will be bottled in the region of production; one day, too, all Tequila will be pure agave. These ideals might seem more distant than ever under present crisis conditions, but it's only by taking aim at them, and working steadily to achieve them, that Tequila can mean most to its drinkers, and most reward its producers.

Andrew Jefford

If you want to know more about the Tequila market in general and the latest figures since the agave crisis struck the industry, please click here for Canadean's overview of the market.