Roadside Raspberries

I'm spending a little time at a lake house about an hour away from St Louis. I went for a walk the other day and discovered these growing anywhere the trees were cut back far enough to give them light, mostly along the roadside:
They're native black raspberries. My grandmother used to pick wild red raspberries in Minnesota, and I valued those jars of jam more than anything else in her vast pantry.

Seeing these berries on the roadside got me a little overstimulated. Over the past week and a half I've made a dozen jars of jam, a pie, and filled a 750ml whiskey bottle (those won't be ready for a few months). If I lived here, I'd freeze some on a sheet tray then keep them in a freezer bag for all my pancake/muffin/smoothie/yogurt needs, but I need my berries to be mobile for now.
I've also picked up ticks, lots of mosquito bites, and a fine network of scratches all over my hands and arms from the thorns of the berry canes. It was absolutely worth it... as long as I don't end up with Lyme disease.

Recipe: Wild Black Raspberry Jam
You can, of course, use frozen berries. The sugar preserves the berries by inhibiting bacterial growth, so don't be tempted to reduce the amount. The lemon and cider vinegar gives the jam a little of that tart edge present in the berries that the sugar tends to mute. I usually use a scale and add 1 cup of sugar per 1 lb of fruit pulp, but it was too big for the travel bag. Use the biggest stockpot you've got. It'll seem like overkill until it starts sputtering boiling stickiness.

Yield: 4-5 jars (if you have a partial, just put it straight into the fridge)

4 cups smashed berries, ~2 lbs
2 cups sugar (unrefined if you've got it)
juice of 1 lemon (and optional zest, finely grated)
1 tablespoon apple cider vinegar

In a large stock pot, combine all ingredients over medium-low heat until juices begin to simmer and sugar dissolves ~5 minutes. Increase heat to medium high and cook, stirring frequently, until it reaches jam consistency* ~10-15 minutes. Ladle into sterile jars and seal.** Store in a cool place up to 2 years. Refrigerate after opening.
* There are a couple ways to check this. If you have an instant read thermometer, the jam needs to reach 220F at the bottom of the pan. Otherwise, put a small plate in the freezer before you start cooking the jam. Once the jam looks to be almost as thick as you want it (it'll thicken as it cools), remove it from heat and drop a spoonful onto your cold plate, let it sit ~30 seconds to cool, and check the consistency. Remember, any jam that doesn't set makes an excellent sauce for pancakes and french toast.

** There are lots of proper, USDA recommended ways to store your jam like a boiling water bath. The common European way is to simply pour the jam into clean jars and seal. At 220F, the jam is actually hotter than boiling water, and as long as you seal it quickly the heat will kill anything lurking in your jars that the sugar and acid won't. If, however, the jam cools too much before you ladle it and/or the lids aren't sealed (the little button pops) after 8 hours, you will need to do a water bath to properly seal them.