On the narrow trails of the Himalayas, where travelers must carry their meals on their backs, multi-use ingredients are essential. Tongba, a brew-it-yourself fermented millet, is one such staple. As long as there’s a steady supply of hot water, one cup of the alcoholic seeds can be stretched into several rounds of warming, yeasty beer.

After allowing the fermented millet to steep for a few minutes, Nepalese drinkers are left with a cloudy liquid. They suck the sour brew through bamboo straws with seed-filtering bottoms until the mug runs dry. Then it’s time for a refill. Often, the millet maintains its flavor and potency even after four or five rounds. But since alcohol content may vary, it might be a good idea to wait and see how the drink hits you: Some say just two mugs can provide a night-long buzz.

The Limbu Sherpas of Nepal traditionally prepared this brew for ceremonies, celebrations, and religious offerings. But cultures in the surrounding mountainous regions of Tibet, Bhutan, and Sikkim in India quickly became fans, as well. Any home-brewer can turn regular cooked millet into tongba by fermenting it in bamboo containers, which usually takes between a week and a month.

Today, restaurants and cafes across Nepal also serve tongba, which is popular among locals and tourists alike. Patrons are encouraged to drink from cask-like vessels (also referred to as tongbas) that they can replenish with pitchers of hot water. Most hot beer skeptics are eventually won over by the appeal of self-administered, bottomless refills.