Pressure cooker vs Instant Pot for grain sterilisation — does it matter?
61 replies · Cultivation
I've seen people use both standard stovetop pressure cookers and Instant Pot electric pressure cookers for sterilising grain jars. My question is: does the type of pressure cooker matter? The Instant Pot max pressure is 11.6 PSI vs 15 PSI for a stovetop canner. Is that difference meaningful for sterilisation?
The difference is real and meaningful. 15 PSI = 121°C, which is the standard autoclave temperature for guaranteed sterilisation. Instant Pot at 11.6 PSI reaches about 116°C. That's still hot enough to kill most things, but you need to extend your cook time — 3 hours instead of 2.5 for quarts, or 2 hours instead of 90 minutes for half-pints.
I ran Instant Pot for 18 months without a single contamination from improper sterilisation. The key is extended cook time and proper technique (not overfilling, using synthetic poly-fil for the filter layer, letting pressure drop naturally). 11.6 PSI works fine if you compensate.
Also worth noting: altitude affects this. At 5,000 feet, your stovetop 15 PSI cooker is also underperforming. If you're in Denver or similar elevation, even 'proper' pressure cookers need extended times.
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