Tasting agave spirits at altitude

Lower atmospheric pressure means volatile compounds leave the surface of a liquid more readily. In practice, the nose of a high-proof spirit arrives faster and hits harder in Denver than it does in Houston. A mezcal bottled at fifty-two percent that reads as expressive at sea level can read as sharp and closed here, with the ethanol crowding out everything behind it.

The usual conclusion people draw is that they dislike high-proof agave spirits. Often the real problem is presentation, not preference.

• Add a few drops of water, then wait. Water lowers the alcohol concentration at the surface and lets heavier aromatic compounds come forward. This is standard practice for whisky and it works at least as well for agave spirits. Start with three or four drops in a half ounce.
• Give the glass more rest than you think it needs. Ten minutes is not excessive. A freshly poured mezcal at 5,280 feet is not ready.
• Use a wider vessel. The traditional copita or a small tumbler disperses alcohol vapour better than a narrow tulip glass, which concentrates it directly under the nose.
• Nose with your mouth slightly open. It sounds like affectation. It measurably reduces the burn and lets you find the actual aromas.
• Drink water alongside, more than usual. Dry air and altitude both accelerate dehydration, and dehydration is responsible for a large share of what people attribute to the spirit itself.

There is a persistent belief that alcohol is stronger at altitude. The evidence for a direct effect on blood alcohol is weak. What is well established is that altitude on its own can produce lightheadedness, fatigue and headache, and those symptoms overlap almost perfectly with feeling drunk.

The practical consequence is the same either way. If you have recently arrived from a lower elevation, your judgement of how much you have had is less reliable than usual. Go slower than you would at home, especially in the first day or two.