Pressure Cooker or Pressure Canner for flasking?

[snow]

thanks dave. i guess the microwave is out.

[John]

Hi Becca, I use a pressure canner and it works really well. Mine is a Presto 23qt size. I generally do a double batch of media (2 liters) and spread it between 16 pint jars. This size canner will hold the 16 jars. If you only do 8 jars of media you can then add a few jars of water to sterilize also. Mine has a rubber seal around the lid but the more expensive ones are metal to metal. Don't know which is better.
John

[Royal]

Hey Becca,

They are pretty much the same thing. They are designed for different purposes, but the concept is the same. Increasing the pressure increases the boiling/evaporation point allowing the temperature to rise above 212 F. Since boiling water is only 212 F (100 C), it only sanitizes. Since some spores can tolerate boiling temps, higher temperatures must be attained for true sterilization. Building the pressure to 15 psi raises the evaporation/boiling point enough for the water and steam to achieve sterilization temps. Boiling at 15 psi for 15 minutes will do - no matter what you call the vessel.

[Becca]

Hi Royal, good to see you back on the OB after the hurricane. I hope all is well for you and your family!

[Royal]

Thanks! As for the heat-up and cool-down periods, the only one you really need to watch is the heat-up. Steam from the water will build and vent before all of the media is boiling (especially if you are doing a large batch). It's a good idea to let steam vent for a few minutes before starting to build pressure. I also go for about 17 minutes just to be sure. Cool-down is irrelevant as long as you hit the right temps for enough time.