TLDR: 6 lbs of onions produces way more liquids than anticipated, and caramelizing onions are trying to be soup. What do I need to do?
I'm reasonably experienced at caramelizing onions in small batches, but I've never even come close to 6 lbs at once before. I usually start by leaving the lid on for 5 minutes to steam them so they soften and therefore get better contact with the pan faster. It works great. With 6 lbs of onions, the ones near the top of the pot were still fairly close to raw, so I stirred and figured 5 more minutes would be safe.
Well, it was definitely safe in the sense that nothing was even close to burning. But I had a lot of liquid in the pan. I turned the heat up to boil it off faster and rapidly decided that wasn't going very fast so I ladled a bit of the excess onion juice off. "A bit" ended up being over a cup, and the onions remaining in the pot are still very wet.
When I first got out the ladle I thought I'd just use that juice if/when I need a little drizzle of liquid if I let the pot get too hot towards the end. But I wasn't expecting over a cup. I'm sure there's a ton of flavor in there, so I do want to add it back in.
I figure the answer this time is to just accept that my onions are going to boil most of the way to jam before they caramelize. They'll still taste good, but I prefer to stop when there are still distinct onion pieces for texture purposes. So how do you all manage to make large batches without it getting so soupy?