People often use the terms "jam" and "jelly" interchangeably but they are distinctly different. Jelly, as stated above, is fruit juice that is sweetened and thickened. Jam, is made from the whole fruit cooked down until thick. It is still sweetened. Preserves are the same as jam but have noticeable chunks of fruit in the mix as well.
Blueberry jam is slowly becoming my yearly tradition although I am not yet growing the blueberries. Last year I went to New Jersey and picked them myself. This year I was blessed with quite a lot of blueberries that needed to be used up at once. Now it should be stated that I like jelly just fine but it always seemed like a lot of extra work to me. You can achieve a certain jelled, smooth texture that is just not possible in making jam, even when it is well pureed but you also loose some fiber in removing all the skin and seeds of the fruit. I mostly make jam out of laziness and lack of concern for perfect texture. Its sweet and fruity and spreadable and I'm happy.
Last year I only ended up making about 3 jars of jam. I had cooked it down so far that it is incredibly concentrated and wonderful. It is not necessary to go that far, however. What I learned on repeating my efforts this year, was that it needn't be the texture and thickness I desired while still hot on the stovetop. It thickens up considerably while it cools. A test I saw somewhere on the internet was to take a spoonful and plop it on a plate, put it in the freezer for 3 mins (so the jam becomes room temperature quickly), then take a spoonful and plop it on a plate again. If it holds a domed shape it has become thick enough and if it spreads out then it still needs to cook more.
Blueberry Basil Jam
(recipe doubled from put em up)
16 C blueberries
1/2 C lemon juice
4 C sugar
1/2 C basil
(That quantity of basil is for half the batch. I packed up half the jars as plain blueberry jam, then added basil to the remainder)
Boil blueberries with a splash of water.
Mash and stir for 5 minutes.
Add sugar and stir until dissolved.
Add lemon juice.
Cook at a steady boil, stirring frequently.
Let rest for 5 minutes, stir, then pack in cans.
See above notes for a good way to test when its done. I ended up cooking for about an hour and a half. I did not puree but you can if you prefer a completely smooth jam. Mine is a little lumpy and Im fine with that. The longer you cook it, the less you'll end up with but the more firm and intensely flavored it will be
The basil sounds a bit unusual but really is quite nice. Doing a half batch "normal" is a nice way to see the subtle difference that a fresh herb can add to jams.It makes for a more unique peanut butter and jelly or a more unique gift.