Posted by Humming Furnace (11/15/16 01:44 PM)
Hello.

This is my first time here and hope won't be the last. I got a Q. I am using a Presto PC and can't keep steady on 15psi. If i am not monitoring the pressure gauge, the PSI will reach over 16psi and even 17psi if i don't bring down the stove head to number 3 or 4.....Is a higher PSI over 15 good or bad, and if higher is good for how long should i sterile for? I usually go the full 90 min....
ANY THOUGHTS OR SUGGESTIONS WILL BE VERY HELPFUL.....got maggots and contamination too but i kind of took care of that.....thank you in advance
Posted by smileyau (06/11/10 09:42 PM)

This is a little misleading because a pressure of 30PSI is really needed to get water to boil at 250?F/121?C.  A 15PSI Pressure Cookers should really be labelled 15PSI ABOVE AMBIENT PRESSURE and because the atmosphere at sea level is 14.7PSI, then at sea level a 15PSI Pressure Cooker will only reach 29.7PSI and a temperature of just below 250?F/121?C (about 248?F/120?C).

The higher you are, the less effective the Pressure Cooker will be and the longer you will have to sterilise for.  At 30PSI a minimum of 15 minutes is required for sterilisation, so at sea level a 15PSI Pressure Cooker requires a little longer than 15 minutes and higher altitudes will require longer.

Smiley