Flasking in jam flasks?
 

Hello, thanks for your help.

I have been propagating some orchids from seed fairly well using "proper" lab brand flasks like here:

https://i.ibb.co/WHTMNwY/20210402-115927.jpg

However, these lab flasks are getting really expensive and hard to get, so the other day I was walking around my house and realized there's a distributor for what I call "jam flasks", because they're used for packaging jam that you can get in the supermarket. I went in and they even gave me a sample of their flasks:

https://i.ibb.co/zN4PcXS/20210402-115411.jpg

They have those airtight caps for jam like these:
https://i.ibb.co/vLTDyJ0/20210402-115440.jpg

My main worry is that since these go in the pressure sterilizer, while lab flasks have an "inert plastic" lid, these have a metal lid with that gummy substance on the underside which could start releasing something that will affect/kill the orchids when heated.

If I'm just being paranoid, are these OK for orchid micropropagation in general? Has anyone had any experience using these or similar flasks for micropropagation?

Thanks, and I hope you have a nice weekend.

You don't want a tight seal on the flask. Oxygen and CO2 exchange is necessary, but dust and spores must be excluded. I know you can get lids with holes over which you affix a filter.

I use similar glassware for micropropagation. Jam jar, mason jars, baby food pots, pretty much whatever will work just fine.

Gas exchange isn't that important when sowing seeds, as you should replate the seedlings fairly frequently anyway.

How frequently, if I may ask?

Ideally before the flask gets very crowded and seedlings start forming clumps. Then it gets harder and harder to separate them without doing damage.