Tequila used to be simple. If it was clear, it was unaged; light gold was reposado, literally “rested”, in oak for a few months; if brown, it was añejo, aged for between one year and three; and dark brown, it was extra añejo, aged longer. Then along came cristalino and skewed everything.

Cristalino is aged (sometimes blended añejo and extra añejo) but, as its name suggests, is crystal clear. An extremely clever (extremely secret) filtration system removes the colour that ageing in wood lends the liquid, without stripping out the rich flavours imparted by the barrel.

Maestro Dobel 50 Cristalino

Who invented the process is a matter of debate. There is a claim that Don Julio González Estrada came up with it shortly before his death, while José Cuervo founder Juan Beckmann Vidal claims the first true cristalino was his luxury tequila brand Maestro Dobel Diamante. What is certain is that the style has been perfected in the latter’s latest release, its even more premium series of limited-edition releases, Maestro Dobel 50.

You might ask, what is the point of ageing a tequila only to strip out the wood colour – and, inevitably, some of the flavours imparted? Why not just enjoy a well-made blanco? The reason is partly what maturation takes out of a spirit. Just like new-make spirit (aka white dog in the US) mellows with age in oak to become a rounded, smooth whisky, some of the more challenging notes in tequila – hints of rubber and acetone, or green vegetables – are taken out of the liquid as it osmoses in and out of the charcoal layer in a charred cask.

Some people enjoy those outlier flavours in tequila; many more do not. Yet they still want the fresh, bright look of a clear liquid. Thus cristalino.

Cristalino is aged but is crystal clear due to a special filtration process

The clarity of Maestro Dobel 50 Cristalino (RRP £199) is quite the accomplishment because it was, to return to our original colour palette, very brown. It is extra añejo tequila, which was aged in both American oak, known for its buttery vanilla character, and European oak, which tends to give a spirit more spice.

The result is a smooth, silky sipping tequila (although, sure, some people will mix margaritas with it – one hopes not with cheap triple sec and bottled lime juice). It offers aromas of caramel, honey and dried fig, with hints of chocolate, tobacco and nutmeg. Some of the cooked agave character lingers in the form of herbal notes. On the palate, the creamy mouthfeel carries fruity flavours – quince jelly, date, pineapple and pumpkin, with cinnamon and vanilla lingering on the finish.

Maestro Dobel 50 Cristalino (RRP £199, 70cl, 35% ABV), available from house-of-spirits.co.uk;maestrodobel.com