Small-Batch Blackberry Jam

Blackberry season is one of the busiest times of year for anyone who likes to can. It seems like just about everything is in season and all needing to be processed at the same time. Gardens are bursting with fresh produce, and depending on where you live you can gather more than enough blackberries to make jam from the edges of fields where blackberries grow wild.

This blackberry jam recipe is a simple small-batch jam that highlights the rich, sweet flavors of the berries without adding anything superfluous. When you have perfect, ripe fruit there’s really no need to add other flavors.

Do You Need Pectin To Make Jam?

You may be wondering whether you need pectin to make blackberry jam. In theory, you don’t. If you boil blackberries with sugar long enough the mixture will jell. However, we prefer to use pectin for blackberry jam for two reasons. One, blackberries are a low-pectin fruit, meaning it would take longer to get the jam to the jelling point without pectin. 

Two, longer cooking times change the flavor of the fruit. Because we wanted this jam to have the freshest, brightest blackberry flavor, we use pectin so we don’t have to cook the fruit very long, allowing it to retain more of its flavor.

What Is Pectin?

What Is Pectin Anyway?

Pectin is a perfectly safe food additive. In fact, it comes from citrus peels and is usually sold as a flavorless, odorless powder. You can make your own pectin from citrus or apples and use it instead of store-bought pectin. You will need 3/4 cup homemade pectin for this recipe. Be aware that due to many variables homemade pectin is not as reliable as store-bought, so you may need to boil the jam longer than directed in the recipe.

Testing for The Jelling Point

Even though commercial pectin is very consistent and reliable, it’s always a good idea to test the jam to make sure it is at the jelling point and avoid runny jam. Place a few small saucers in the freezer when you start making the jam. 

When you think the jam is ready, take the pan off the heat and drop a small spoonful of jam onto one of the chilled plates. Place the plate back in the freezer for one minute. Run your finger through the jam slowly. The surface of the jam should “wrinkle” as if a skin is forming on top. When you run your finger all the way through it, the jam should not run back together right away but your finger should leave a trail that very gradually fills in.

If your jam doesn't pass this test, keep boiling it, testing it every few minutes.

Ways To Use Blackberry Jam

Other than the obvious use on buttered toast, use your blackberry jam for:

• One-Bowl Oatmeal Jam Bars
• With yogurt and granola
• Jam Swirl Coffee Cake
• Spread a thin layer between cake layers in addition to the frosting
• Kolache Cookies

Canning Equipment Needed

You will need the following items to make this blackberry jam:

• 4 half-pint glass canning jars with bands and new lids
• Large, deep pot, such as a stock pot
• Canning rack, clean kitchen towel, round cake cooling rack, or a silicone trivet
• Jar lifter
• Potato masher (or other tool to mash blackberries)
• Ladle
• Canning funnel

Recipe Tips

• What is “fingertip tight?”—Screw bands onto jars until you feel resistance when turning, this is fingertip tight. Air must be able to escape from jars while boiling. If air cannot escape, the lids may not seal. 
• Use new lids every time—You can reuse bands but you cannot reuse lids. The compound along the edges of the lids softens during processing. The disturbed layer of compound may fail to properly seal jars if used again.  
• What to do with extra jam—The final amount of jam you end up with can vary depending on the fruit and how long it is boiled. If you have slightly more than four half-pints of jam, you can either refrigerate the excess and use it within a couple weeks or you can sterilize an additional quarter-pint jar (sometimes called a jelly jar) and process the extra jam as well. These tiny jars make great host gifts.
• No canning rack? No problem—You can use a round cake cooling rack, a round steamer rack, a silicone trivet, or even a folded clean kitchen towel if you don’t have a canning rack. 
• How to time jam processing—When canning, start the timer once the water comes to a boil. 
• Checking for a seal—To check if the lid is properly sealed, remove the band and hold each jar by the lid above the work surface.
• Don’t use fresh lemon juice—Use bottled lemon juice, not fresh. Bottled lemon juice has a uniform pH, whereas fresh lemon juice pH levels differ due to the fruit’s variety, ripeness, and age.