Here’s the short answer: to reliably kill most harmful bacteria in water, you need to bring it to a rolling boil of 100°C (212°F) or, for pasteurization-style safety, hold it at 70°C (158°F) for at least 30 seconds. Wait, why two numbers? Because heat is a slow dancer—it needs time to waltz through the bacteria’s defenses. Boiling is the gold standard because it’s easy to confirm (bubbles!), but lower temperatures can work if you’re patient.
Think of it like cooking a steak: you don’t need a blowtorch to kill germs if you give them a long, cozy stay at medium heat. But for water, most experts agree that a vigorous boil is the safest bet for outright destruction. Cool, right? Your kettle is basically a bacteria assassin.
Why Heat Kills (It’s Not Magic, It’s Protein)
Bacteria are little bags of proteins and enzymes that keep them alive. When you heat water high enough, those proteins start to denature, which is a fancy way of saying they unravel and stop working. Imagine a wool sweater shrinking in the wash—same idea, but with germs. At 60°C (140°F), some bacteria start sweating, but at 70°C, the party’s over for most pathogens like E. coli and Salmonella.
It’s actually fascinating that a simple temperature change can cause this molecular meltdown. You’re not just boiling water; you’re scrambling the very structure of life. Yet, you do it every time you make tea.
