Last year, I didn't take is so easy on myself with preserving blueberries (of course, last year I had access to a large stock pot I could use for water bath canning, so that made a difference. Last year, I made a ton of blueberry sauce for pancake/waffle topping, ice cream topping, and yogurt flavoring (okay, I hadn't started making my own yogurt yet when I made it, but we've been using it for that purpose more than any other the past few months!). I made a couple batches: the first I screwed up somehow, but it made a thicker sauce, so I thought that was nice. I didn't actually realize that I'd made a mistake in the recipe until I followed it exactly (well, as exactly as I ever follow a recipe) and it ended up being a lot thinner. I present here the recipe I used the second time, but I think it is safe to say that the water could be reduced (somehow. Really, this recipe is so simple, how did I screw it up?!?!) if you want a thicker sauce. It can be frozen or canned, with no noticeable difference in end result.
2 quarts blueberries, rinsed and drained
2 cups water
3 cups white sugar
4 cups water
2 tbsp lemon juice
Mash blueberries in a large pot. Add 2 cups water and simmer over low heat for 5 minutes.
In a large saucepan, mix sugar and 3 cups water. Bring to a boil, stirring occasionally until temperature reaches 260 degrees. Add blueberries; boil for 1 minute. Stir in lemon juice and remove from heat. Let cool.