Temperature to Sterilize Jars in Ovenに関する主要なデータを分かりやすく解説いたします。

Here’s the gold standard: 275°F (or 135°C for the metric crowd). That’s the sweet spot where heat kills bacteria, yeast, and mold spores without stressing your glassware.

Why not 250°F? Too low—you’ll just give the germs a warm bath. And why not 300°F? That’s tempting, but it can cause thermal shock, especially if your jars are cold from the dishwasher.

Think of it like this: you want a steady, gentle sauna for your jars, not a fire-breathing dragon. Your grandma’s canning book might say 225°F, but modern safety guidelines bumped it up because we’ve gotten smarter about Clostridium botulinum—that’s the villain behind botulism.

Step-by-Step (So You Don’t Cry Like Clara)

First, wash your jars in hot, soapy water. Rinse them well—don’t skip this, even if they look clean. Then place them upright on a baking sheet, leaving space between each one.

Pop them into a cold oven. Yes, cold. Preheating first is a recipe for shattered glass. Trust me, I learned this the hard way when a jar exploded and I found glass in my muffin tin three weeks later.

Now crank the heat to 275°F and set a timer for 20 minutes once it hits temp. If you’re doing taller quart jars, go for 25 minutes—more thermal mass needs a little extra love.