When we first started distilling rum in the Colorado Rockies, we spent a lot of time explaining that high-altitude rum isn’t a new idea. There’s actually a long tradition of it that we’re lucky to continue. In fact, it was the discovery of the mountain tradition of rum that led our founder Karen Hoskin to believe making rum in Colorado wasn’t such a crazy idea! Our name, Montanya Distillers, is actually a nod to this mountain tradition (Montaña is the Spanish word for mountain, and we added the “Y” so we could trademark the name.)

Distilling and aging Montanya Rum at almost 9,000 feet above sea level benefits the process and the final product, from energy use to flavor. Here’s how:

A Lower Boiling Point Leads to Better Flavors

Anyone who’s cooked pasta at elevation knows that water takes longer to boil—the pasta also takes longer to cook, and it feels so darn easy to end up with a pile of mush. That’s because liquids boil at lower temperatures at elevation—in Crested Butte, water boils at about 195 degrees (compared to 212 degrees at sea level).

The same is true for alcohol. At sea level, the boiling point is around 173 degrees and it also decreases with altitude. As you can imagine, that has implications for distilling when it comes to heating up the wash in the still. (Need a crash course in distilling? Check out Making the Rum and the Rum Distillation Process.)

The goal is to heat the wash at a rate that allows the distiller to pull out different alcohols at different times. Get a mad boil going and this is phenomenally difficult to do. Heat it up too slowly, and the alcohols may never leave the still.

Because of our boiling temps, we can actually extract the alcohols more quickly with less energy and less input. In the words of our founder Karen, the wash and alcohol don’t get beaten up as much in the still. All of that leads to more of the various flavor molecules making it from the wash into the final product, so that our rum is tastier distilled at altitude than it would be at sea level.

Easier to Control Temperatures

Another fun fact about life in the mountains is that high-altitude lakes stay cool all summer long. In late summer, for example, you’ll never hear someone refer to lake water as bath water. While that makes a dip in the local watering hole a bit brisk, it benefits energy use during the distilling process.

At altitude, the lower boiling temperature allows us to ferment our yeast and sugar cane longer than many distilleries at lower elevations.

First off, we can control the temperature of the fermentation tanks with tap water alone. On the hottest day in the middle of July, our water comes out of the tap at 42 degrees. On the coldest day in the middle of January, it sometimes comes out at 36 degrees. If the tanks get too warm, all we have to do is run tap water through the copper coils inside the fermenters and it cools the fermentation down. This keeps the fermentations from running too warm and killing off the yeast.

Likewise, we can use tap water in the condensers that turn alcohol vapors from the stills back into liquid. (To be clear, we’re not adding tap water to the rum but using it to control temperatures and return vaporous rum back to liquid form). Most rum distillers in the islands or other warm locations have to install what are known as wort chillers to accomplish the same thing, adding extra energy use into the system.

A More Dynamic Aging Process

When Karen hosts tastings at rum events, she commonly hears that our rums have a bit of a chili flavor or spice to them. She attributes that to a combination of the sugar cane we use and the barrel aging process; the whiskey once stored in the barrels has a little bit of that chili spice that has worked its way into the wood. (It may also be true that our whiskey barrel partners value a bit of spiciness as much as we do.)

Our rums pick up a lot of other flavors from the barrels, too, from vanillans (which translate into vanilla flavors) to sucrose (a natural sweetness). And at altitude, the rum naturally moves in and out of the barrel pores more often.

If we made rum at sea level and put it into an empty oak barrel, 20 to 25% of the rum would move into the pores of the barrel on day one and stay there. The other 80 to 85% of the rum would stay in the center of the barrel and never actually come into contact with the wood.

That’s why some distillers roll barrels or agitate them with sonic waves. Karen and Brice once met a distillery owner who put his barrels in submarines to get the spirits to move in and out of the barrel. Another distiller uses reactor technology to try to introduce natural age through a scientifically accelerated process. Thankfully, altitude takes care of that for us.

At Montanya Distillers, we age and bottle our rum at a distribution center two miles south of our Crested Butte tasting room and distillery.

We get such radical fluctuations in temperature from the start of the day to the finish of the day and from winter to summer that whatever rum is in the pores of the barrel during the day gets pushed out of those pores at night. New rum gets pulled into the pores the next day, and it’s constantly on the move. Kinetic action like this is fairly rare in the world of rum. The variations in temperature also allow more chemical reactions to be activated in the barrel that are common at sea level in a consistently warm environment.

As Karen explains it, in Scotland where temperatures are cooler, spirits tend to absorb more wood, peat, char and oak flavors (what some might call dirty socks 😆). In the Caribbean, warmer temperatures yield more of the vanilla, butterscotch, and fruity flavors like pineapple. At our altitude at Montanya Distillers, we’re lucky enough to get a very broad spectrum of flavors not often associated with Rum—everything from the leather, char and peaty flavors to the butterscotch, pineapple, coffee and pear.

Want to learn more? If you’re in Crested Butte, stop by for a visit. We offer tastings, and you can taste the difference for yourself!