Craft Beer & Brewing Magazine® is headquartered in Fort Collins, Colorado, and thanks to recent amendments to our state’s constitution, we’ve grown accustomed to (and a bit weary of) the occasional comment about certain botanical relatives of _Humulus lupulus. _But when we talk about brewing high, we’re specifically referring to elevation. After all, we’re almost a mile above sea level.
It’s well known that cooking—baking, especially—at high elevations sometimes means adjusting recipes. The same is true for brewing, but the effects are probably not as great as you might think. If you brew your beer at high elevation, here are the main points to keep in mind.
Lower Boiling Point
Water boils at 212°F (100°C) at sea level, but the boiling point drops by 1.9°F (1.06°C) for every 1,000 feet (305 meters) you climb in elevation. This is because the air pressure decreases with distance from the center of the earth, and the boiling point of water is directly related to air pressure. Here are a few examples of how the local boiling point changes.
- In Denver, Colorado, at 5,280 feet (1,609 meters), water boils at 202.5°F (94.7°C).
- In Santa Fe, New Mexico, at 7,199 feet (2,194 meters), water boils at 198.9°F (92.7°C).
- In Cusco, Peru, at 11,000 feet (3,353 meters), water boils at 191.7°F (88.7°C).
Practically speaking, a lower boiling point means that brewers who live at high elevations need to account for that lower temperature when calculating recipes. It may mean slightly increasing your volume of strike water or of any hot water infusions you use to raise the mash temperature. It takes more water to achieve the same temperature change since that water holds less heat.
Incidentally, there’s nothing magical about sea level. It’s just an arbitrary reference point to measure distance from the center of the earth. If you happen to brew your beer in Death Valley or on the shores of the Dead Sea, then the boiling point of water actually climbs to 212.5°F (100.3°C) or 214.4°F (101.3°C), respectively.
Decreased Hops Utilization
Along with the lower boiling point of water comes a lower boiling point of wort. And since it takes heat to convert hops alpha acids into bittering iso-alpha acids, it theoretically takes a touch more time (or a touch more hops matter) to achieve the same level bitterness versus a sea-level brew. In practice, however, the difference is fairly negligible, about 5 percent more hops material for every 1,000 feet (305 meters) in elevation gain.
More Boil Off
High elevation is usually associated with low humidity. It doesn’t have anything to do with the elevation itself, but rather with the lower air density, pressure, and temperature that accompany that change in elevation. And, as we’ve seen earlier, the higher elevation also means a lower boiling point, which translates into more water vapor loss for the same amount of applied heat.
All of this is to say that water vapor from the boil is generally more readily lost to the atmosphere at high elevations, so the same equipment setup that loses a gallon (3.8 liters) per hour at sea level might lose a gallon and a half (5.7 liters) per hour in Denver. Practically speaking, it’s hard to quantify this effect, especially since so many other variables are at work: Kettle geometry, burner size, and even the weather all play a role. Your best bet is to take good measurements when you brew so that you can dial in your system’s behavior.
Higher Keg Pressures
This one is sometimes overlooked, but it’s a biggie. When you calculate the required gauge pressure for a given beer style, remember that the gauge is measured relative to the ambient air pressure. The ambient pressure drops by about 0.5 pounds per square inch (psi) for every 1,000 feet you climb in elevation (for our metric friends, that’s about 1.2 kPa per 100 meters of gain).
This means that when you set the gauge pressure on your carbon dioxide regulator, you need to make up for that pressure drop in the serving pressure that you apply to your beer. It’s dead simple, though. Just add 0.5 psi per 1,000 feet (1.2 kPa per 100 meters) to the pressure you calculate when you balance your keg system.
In the end, brewing at high elevation isn’t all that different from brewing at sea level. A minor tweak here and a little adjustment there are small compared to the big stuff such as mash temperatures and hops timing. But, in the ongoing quest to brew the perfect batch, those little adjustments might just be what it takes to give you the natural high that comes from crafting something beautiful.
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