Ever pressure cook jars without foil?

Was wondering if anyone knows what happens when you don't put alu foil on the lids of the jars when pressure cooking your grain?

If you have a filter in your lid like you should, either polyfill or the premade ones, you’ll get moisture into your jars and throw off the water content in your grains.

I haven’t ever done it without, who knows it might work. But for my situation I already have my grains at the moisture level needed for quick spawn.

I think next time I run some jars ill try a couple without the foil and post back the results.