Colonization rates are pretty variable. To give a typical example, on Dec. 18, the day after you inoculated your jars, I started two sets of six BRF jars. I used two spore syringes from the same supplier, one Chitwan and the other Hawaiian. The Chitwan jars took off, and have fully colonized. They're white as snow, and ready to birth. Most of the Hawaiian jars show very little growth (only one has large areas of growth, and some have none).
It can be hard to pinpoint the cause of differential colonization rates. In this case, a genetic cause seems likely (Chitwan has a reputation as an aggressive colonizer); but it is also possible that this particular Hawaiian syringe was poorly prepared. To know, I'd have to do a parallel grow with multiple syringes from the same genetic stock.
About the same time, I inoculated a couple of batches of rye-grain spawn, using agar cultures isolated from a Cambodian print. Half are in 1L wide-mouth mason jars, and the others are in Ziploc Twist n' Loc containers. Both have similar air-exchange holes (3/8 inch holes, covered with three layers of micropore tape). The Ziploc jars have colonized much more quickly. Again, it's hard to say why. Maybe the Ziplocs, with their wider aperture, are getting better aeration? Or maybe the shaking was more uniform, because of the shape of the containers and the no-stick plastic? I guess I could get all scientific about it, and do some more side-by-side grows, but I'll probably just switch over to Ziplocs for all my grain spawn.
As for the pressure cooker: bigger is better. For half-pint BRF jars, you can get away with a smallish pot, but if you stick with this hobby, you'll soon want to sterilize larger jars, and/or bags of spawn. As I recall, a 16 quart pressure Presto is tall enough for litre-size jars. I really like the 23 quart Presto, which I picked up for $140 CAN, at a local hardware store (the All American pressure cookers are superior, but also a lot more expensive). If possible, get one with a gauge. If you can't see the pressure, it's tempting to blast the pot with too much heat, which can lead to excessive water-loss, and even "doming" of the aluminum bottom (did this twice, back in the 80s!).
By the way, why have you kept that foil on your jars? The dry verm layer above your BRF provides sufficient filtration of contaminants...as long as you don't jostle them too much, or keep them in a really foul place.
Edited by WalkingCatfish, 29 December 2018 - 10:02 AM.