Oh I totally understand WHY. My point is that during that time the water is boiling which means the beans are cooking. And then from the time you put the pressure regulator on until it reaches pressure is another 10-15 minutes during which the water is still boiling so the beans are cooking. Then if you cook them under pressure for the recommended 25 minutes, when you add it up, you've been cooking the darned things for 45-50 minutes which in my opinion is WAAAAY too long, and cooks all the nutrients out of them.HEChicken the reason for leaving the vent open is to get all the excess air out so the heat rises faster. Once the steam starts I put my regulator on and adjust the heat when I get to the 10 pounds. Then cook them under pressure for 25 minutes. If you do them a lot longer they loose flavor. It actually has worked well for me especially if I have another load to get ready. I can pack the next 7 jars while the first batch pressure cooks. Non Acid foods require pressure cooking rather than a hot bath. I love home canned green beans. But the way my crop is going this year I doubt I'll be canning anything.
My son freezes his beans but I don't care for frozen green beans.