It was a fun thing to do with him, moving up and down the rows, just the two of us in yummy nature. He loved it, and I'm pretty sure he could have stayed twice as long. Which is good, because local organic blueberries are coming in, and I intend to pick at least 30 pounds to freeze for smoothies this winter.
But back to the jam. My mom told me that she uses half sugar, half fruit, (by weight) and just cooks it until the right consistency. I found this recipe which was basically the same except with measurement rather than weight, and since I don't have a scale, I used it. When I measured the berries, I pressed them down with my potato masher so there wouldn't be a lot of air in the cup and the volume would match that of the sugar.
To sterilize the jars, I submerged them in boiling water and boiled them for 15 minutes, throwing the lids and the ladle I was going to use into the water for the last 5 minutes.
The whole thing is much easier than you may imagine. Put in the berries, put in the sugar, and boil it. My mom advised me that it boils up pretty high, and she was right, so don't overfill your pot. Halfway full is plenty, unless you like the idea of cleaning burning hot sugar off your stove. Because it can boil over, you do have to watch it pretty closely, so I recommend you do this when you can have undivided attention (like, naptime in my case). You also have to keep a close watch for the time when it reaches the right consistency.
To check consistency, I used my mom's method: put a plate in the freezer and periodically drop a bit of jam onto it, and check the consistency of the cold jam. The recipe also advises that it is done when two drops start to run together and fall more slowly off the spoon. You can kind of see this happening. Using both methods, I managed to get the consistency just right. My jam took about 10 minutes to reach the right consistency.
When it's done, ladle it into your jars, trying not to be too sloppy. If you spill on the edge of your jar, wipe it with a clean, damp rag. You can search the internet to learn how to seal jars by boiling them in the oven, but I just used the lazy method my mom and grandmother use--wax. You can buy the wax right next to the jam jars in most supermarkets. Melt it while you are making your jam by placing in a jar, and then placing the jar in boiling water that reaches about halfway up the sides. Pour it onto your finished jam about 1 cm thick. Easy peasy.
A word about wax, though. The last time I tried to make jam was over 10 years ago. I was cooking with gas then, and I melted the wax directly in the pot. When I turned off the gas burner, it gave a little puff, and the flames jumped up into my wax. Suddenly, the pot was full of fire. In a panic, I put the pot in the sink and turned on the water. DO NOT DO THIS. Wax and water are like oil and water. Maybe you all know that already. I didn't. I was totally shocked when I suddenly faced a wall of flames over the sink. Luckily, I was so shocked I thought nothing of reaching into the fire with my oven mitt on and turning the pot over. The fire went right out. I was very, very lucky. If you're cooking with gas, be very careful with the wax.
10 cups of raspberries, 10 cups of sugar, and I have 12 250ml and one 500ml jam jars full of yummy, yummy jam. Start to finish, the whole thing took about half an hour, for each batch. I also made strawberry jam with the same recipe, and it boiled about 15 minutes to reach the right consistency.
Try it out. There's nothing quite like home-made jam, and this way you can have it pesticide free and with organic sugar for much less money. Not that I'm saving much more than $30 bucks a year on jam here...but knowing you made it yourself is somehow priceless. My only complaint is that summer is a cruel time for jam berries to be in season. Standing over a stove with three boiling pots (jars, jam, wax) for half an hour...is an excellent facial, if nothing else.
