I love your tag, I missed that yesterday. It is INCREDIBLY messy, isn't it?! And talk about fruit flies.
But there's nothing like the real McCoy jam. We usually do plums. Or pears. Though we call it plum/pear Compote, rather than jam. I'm no expert, but I stir the stuff every now and then in the pot, to keep even heating and it thickens and darkens. We don't use lemon juice, to keep the color, just the fruit. It gets pretty dark. But it all goes the same place anyway. And it's not for presentation. (Though I have won awards at the County Fair for my stellar plums, and a bit of CASH ( :

We hot water bath the fruit once done. Are you canning them, or just refrigerating/freezing and eating? One needs to study up a bit for canning, or talk to someone who knows, but you probably realize that already. So easy to do, but have to do it right. I get advice from a friend who knows, and so it seems to work.

I let the juice steam off as it cooks. That way it naturally thickens. You don't have to waste the tasty juice by pouring it off either. Do you drink that extra juice? Nothing like real fruit.

We also dehydrate pears and other fruits. Plus, grapes, apples. SO good. And keep a long time, if truly dried out. Good luck in the joys of kreative kitchening and making a huge, but fun mess.