Today we made homemade blueberry jam and did NOT use little boxes of Sure-gel. I’ve made plum jam without added pectin, but this was a first for blueberry jam. It all happened because I got caught out in not reading directions first. I just blithely dumped in crushed blueberries and sugar and turned on the stove. Then I read the little instruction sheet in the Sure-gel box. Shoot. I wasn’t supposed to add the sugar until after the fruit and Sure-gel had done the rolling boil thing. So I switched gears.
It was time to do an experiment and try blueberry jam the old fashioned way. Here’s what I found:
No-pectin-added blueberry jam
Start with a really heavy, large stock pot. The heavier the pot is, the less likely you are to burn the jam. Remember that jam is mostly sugar and sugar burns easily. Crush your blueberries and add equal parts berries and sugar. I chose to cook up six cups of blueberries and six cups of sugar.
I brought it to a boil and then stirred it frequently, although not constantly. It takes too long to cook to be able to stir it constantly! I tried to keep the hot bubbly mixture cooking at a temperature that kept it boiling but not burning. It cooked the berries and sugar for at least 45 minutes, maybe a little more.
As the mixture cooks, you can see it starting to thicken, especially around the edges. There are a number of ways to tell how long to cook it.
Some websites recommend checking the temperature. Because I’m at sea level, I needed to get the jam up to 220°. (You can drop that temperature 2° for every thousand feet up to 4000, then 1° for the increment between 4000 and 5000 and an additional 2° for each thousand feet thereafter.)
A second way you can test if it’s cooked long enough is to put a dab on a cold saucer and put it in the fridge to see if it gels up right away. That doesn’t seem to work for me though.
The third way, and the way that I prefer to use, is by taking a metal spoon, sticking it into the jam and lifting a spoonful about ten inches above the pan. Tilt the spoon and watch how it runs off. When it sheets off the spoon (when two drops form and run together) then it’s done. (I also checked the temperature and it was right at the right place.)
Then I poured the hot jam mixture into the sterilized jars and put on the lids and rings (also sterilized.) I turned them upside down immediately for fifteen minutes and set them on a towel to cool. After fifteen minutes, I turned them back right side up. Within a few hours, all the lids gave that musical little pop as they sealed.
Two interesting things about no-added-pectin jam that I found. First, there was no foam to skim off the top before pouring into jars. Second, there was a very slight taste difference. I can taste that added-pectin contributes its own slight bouquet to jam.
And hey, I saved buying that extra box of Sure-gel!
For another recipe for no-pectin-added berry jam, see this post.