I found this recipe years ago in an old Maine cookbook called “Good Maine Food”. It was book published in 1949 and it has a lot of good old fashioned recipes in it. It didn’t call for any pectin so I was a little nervous the first time I used it as I had become a “pectin-reliant” canner over the years. This recipe was going “old school” but it worked out fine and I have used it ever since. Only 2 ingredients so it doesn’t get simpler than that. I have revamped the instructions for modern day canning equipment.
2 lbs. of blackberries
1 1/2 lbs. of sugar
Wash and pick over your berries. When canning fruit, you only want to use berries that are in good condition, just ripe or even a few that are a little underripe. In a large kettle put a layer of berries, then a layer of sugar, then another layer of berries, and another of sugar until you have used all the ingredients. Let this mixture stand for an hour before you start cooking it. This allows the sugar to draw the juices out of the berries so you don’t have to add any additional liquid. Cook over medium low heat, stirring frequently. You should cook them for 35 minutes till the mixture thickens. Pour the jam into clean, sterilized jars. Wipe the rims clean and then place clean, sterile lids on the jars. Screw on the metal bands and hand tighten. Process the jam using the water bath method for 20 minutes. Adjust time for higher altitudes. Remove jars from canner and allow to cool. Check seals of jars. If there are any that don’t seal properly, refrigerate and use first.