As detailed in the post, wash and hull the berries - this recipe takes 6 lbs of berries
Place helf or the berries in an 8 quart stainless steel pot. and mash with a potato masher, or make a rough puree with an immersion blender.
Add the other half of the berries, the sugar and lemon juice.
Mash everything a little more or run the immersion blender through until you have a chunky mixture with plenty of liquid. No need to get it completely smooth.
Set the burner under the pot to a medium-high level, and stir the mixture VERY frequently until it has become liquid, with all of the sugar dissolved.
Once you begin to see some bubbles around the edge of the pot, lower the temperature to the higher side of low.
Don't walk away! You need to thoroughly stir this at least every 10 minutes, scraping over the entire bottom and into the corners. The more it cooks down , the more often you need to stir it.
After about 25 minutes, check the temperature with an instant read thermometer. You will find it pretty easy to get to 215°F, and after 25 minutes over medium heat, it will likely be right about at that temperature.
Getting to your target temperature takes a bit of patience at this point. It's a good time to reduce the heat under the pan a bit. If you are going to stand and stir it constantly, you don't need to turn it down much, but if you might get distracted, don't risk leaving it too high.*
This proportion of berries and sugar will be nicely thick when it cools, if it gets to a target temperature of 216-218°F. It might take longer than you think it should, but don't take it off the heat too quickly.
I recommend canning these preserves, especially if you make a full batch.I refer you to my recipe for Blueberry Preserves for canning instructions, because I have a very detailed method there already.
Notes
If you cut this recipe down to an amount that you know will be eaten within a month or 6 weeks, you can just refrigerate your finished preserves. In truth, they will probably keep much longer than that in the fridge, but absolutely for that long.These preserves could be frozen - just cool completely before putting in freezer containers.Preserves like this are the easiest thing in the world to can though, so again, I'll refer you to my Blueberry Preserves recipe for canning instructions.Accidents happen, and if you do find yourself with preserves that are burning and sticking to the bottom of the pan, DO NOT scrape up the burned parts. It may still be salvageable, but not if the burned bits get stirred in.Turn off the burner, and allow the preserves to cool a bit. Again, without mixing it, or scraping the bottom, pour the mixture into another pan. Put the new pan back on the stove and proceed, until you get to the temperature stated above. Soak the burned pan and scrub it out. I've done this myself before, and with more than just jam - if you don't scrape up the burned part, it is probably going to be ok.