You want a rolling boil, not those wimpy little bubbles that look like a fishtank filter. Rollin’ means big, energetic bubbles that break the surface like a tiny volcano. When you see that, start your timer. One minute (or three if you’re a mountain goat).
What about altitude? At sea level, water boils at 212°F. At 10,000 feet, it boils at around 193°F. That’s too cool to kill bugs instantly, so you give it more time. The rule: one minute at sea level, three above 6,500 feet. If you’re on Everest, just eat snow and cry.
How to boil perfectly drinking water for purification
And for the love of all that is holy, let it cool before you chug it. Watching someone burn their mouth after a heroic purification effort is both sad and hilarious. I’ve done it. My tongue was a martyr for safety.
The Microwave Heresy
Can you boil water in the microwave? Yes, with caution. Microwaves heat unevenly, so you risk “superheating”—where the water looks calm but explodes when you touch it. Use a wooden stick or a clean spoon to break the surface tension. Or just use a stove. You’re not a microwave magician.
If you microwave your water, heat it until it bubbles for at least one full minute after it starts to boil. Watch it through the glass. Stir it. Then wait ten seconds before grabbing it. Trust me—superheated water is the only time I’ve sworn at a kitchen appliance.
