My very favorite thing to can is jam. Not quick freezer jam. Not “in-a-hurry” pectin-added jam. I prefer to make old-fashioned, long cooking, no-pectin-added jam. Every year I make cases of apricot jam, plum jam, peach jam, and this family favorite, Blueberry-Raspberry Jam. Although Blueberry Jam is good, and Raspberry Jam is even better, the combination is best of all. Here I use equal amounts of both berries, but you could vary the ratio. The important thing is to keep to the overall measurements, in other words, 9 cups of berries.
This particular recipe is adapted from one found in the Ball Blue Book® where they suggest any combination of several different kinds of berries including blackberries, gooseberries or loganberries.I have used this basic recipe with strawberries and blackberries for a Wild Berry Jam concoction, and even Raspberry-Apricot Jam. You can also find more inspiration with Kevin West’s Universal Jam Recipe.
Before starting any canning project, it’s always a good idea to brush up on home canning safety tips. Lessons learned at Grandma’s knee might no longer be considered safe. Mother Earth News has published many canning articles that help keep us up-to-date, including the very helpful Home Canning Guide.
When making pectin-added jams the process is straight forward; follow the directions, add the pectin, let boil for a specific amount of time, and voila, the jam is set. No-pectin-added jams require a bit more magic, in the form of longer cooking, before they reach the gelling point.
Determining just where that point is can be frustrating. It took me years to figure out when the jam had set. It must be a common experience, because the number one search term that sends people to my website is how to fix overcooked jam.
There are three common ways to determine jam gel; the spoon sheeting method, the glass plate method, and the temperature method.
I like to use the plate method to check for gelling. Drip a little bit of the cooking jam onto a glass plate, and put the plate in the fridge for a minute. If it is set the way you prefer, remove the jam from the heat. Note: Most directions tell you to draw a line through the jam on the plate. If it stays separated it is set. However, I prefer my jam on the softer side, so I look more for texture than whether or not the jam stays separated.
Many recipes tell you to use the spoon-sheeting method to check the gelling point. This method works great, but it can be difficult to determine exactly what you are looking for if you are new to canning. In the spoon-sheeting method you watch to see if the jam drips off the spoon or if it sheets of the spoon. When it sheets, the jam is set.
The temperature method is easiest of all. Here you use a candy or digital thermometer to determine gel. The jam is set when eight degrees above the boiling point of water, which is usually 220 degrees for those of us below 1,000 feet in elevation.
• 4-1/2 cups fresh or frozen raspberries
• 4-1/2 cups fresh or frozen blueberries
• 6 cups sugar
1. Combine sugar and berries in a large saucepot or Dutch oven.
2. Don’t forget to rub butter along the inner lip of the pot so the jam doesn’t boil over!
3. Bring the berry/sugar mix to a boil over medium heat, occasionally stirring until the sugar dissolves. Once the mixture comes to a boil, turn the heat up just a little so that it rapidly reaches the jellying point. I like to stir constantly to this point so that I don’t end up with a lot of foam that needs to be skimmed off.
4. Pour into clean jars, wipe the jar lip with a damp paper towel, and cover with the two-part jar lids. The jam is a beautiful magenta color, quite different from either raspberry or blueberry jam.
5. Process in a water bath canner for 15 minutes. You can find my step-by-step Water Bath Tutorial on my website.
Yield: 7 half-pints
What kind of berry jam have you made this year? What is your favorite combination?
Renee Pottle is an author, Family and Consumer Scientist, and Master Food Preserver. She writes about canning, baking, and urban homesteading at SeedtoPantry.com
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