Sorry, my mistake - I don't do any canning. Yes you'll drive out any oxygen through the vent. Actually you probably can't boil with lids tight as they might explode...
What I'm doing is different. I preheat a jar and then half fill with boiling wort made from extract. I then screw the lid on immediately while blowing out steam. The heat sanitises the air in the air space. Shake to aerate when cold. It won't kill the most heat resistant bacterial spores so not suitable for long term storage but great for immediate use.
Topic: Yeast Freezing/Storage (Read 5920 times)
