combination of blueberries and rhubarb is less common than the typical
strawberry-rhubarb pairing, but it really shouldn’t be — this lovely, deep blue
jam is a delicious, tangy treat. This recipe was adapted from one by jam-maker Kirsten
Jennings, who first tried it at a local restaurant and liked it so much that
she figured out how to make it at home herself.
Before You Begin:
calcium water. To do this, combine 1/2
teaspoon calcium powder (in the small packet in your box of Pomona’s pectin) with 1/2 cup water in a
small, clear jar with a lid. Shake well.
Extra calcium water may be stored in the refrigerator for future use.
Yield: 4 to 5
half-pint (8-ounce, or 236 ml) jars
1 pound (455 g) blueberries
1 pound (455 g) trimmed rhubarb
1/2 cup (120 ml) water
1/4 cup (60 ml) lemon juice
2 teaspoons (10 ml) calcium water
1 1/4 cups (250 g) sugar
2 1/2 teaspoons (7.5 g) Pomona’s pectin powder
1. Wash your jars,
lids, and bands. Place jars in canner, fill canner 2/3 full with water, bring
canner to a rolling boil, and boil jars for 10 minutes to sterilize them. (Add
1 extra minute of sterilizing time for every 1000 feet above sea level.) Reduce
heat and allow jars to remain in hot canner water until ready to use. Place
lids in water in a small sauce pan, heat to a low simmer, and hold until ready
blueberries, remove stems, and mash in a large bowl. Set aside.
rhubarb, slice stalks lengthwise into thin strips, and then dice. Combine diced
rhubarb in a saucepan with the 1/2 cup (120 ml) of water. Bring to a boil over
high heat, reduce heat, and then simmer, covered, for 5 minutes, or until
rhubarb is soft, stirring occasionally. Remove from heat and mash rhubarb.
4. Measure out
2 cups (473 ml) of the mashed blueberries and 2 cups (473 ml) of the mashed
rhubarb (saving any extra for another use), and combine the measured quantities
in a saucepan. Add lemon juice and the calcium water, and mix well.
5. In a
separate bowl, combine sugar and pectin powder. Mix thoroughly and set aside.
6. Bring fruit
mixture to a full boil over high heat. Slowly add pectin sugar mixture,
stirring constantly. Continue to stir vigorously for 1 to 2 minutes to dissolve
pectin while the jam comes back up to a boil. Once the jam returns to a full
boil, remove it from the heat.
Your Jam: Remove jars from canner and ladle jam into hot jars, leaving
1/4 inch of headspace. Remove trapped air bubbles, wipe rims with a damp cloth,
put on lids and screw bands, and tighten to fingertip tight. Lower filled jars
into canner, ensuring jars are not touching each other and are covered with at
least 1 to 2 inches of water. Place lid on canner, return to a rolling boil,
and process for 10 minutes. (Add 1 extra minute of processing time for every
1000 feet above sea level). Turn off heat and allow canner to sit untouched for
5 minutes, then remove jars and allow to cool undisturbed for 12 to 24 hours.
Confirm that jars have sealed, then store properly.
can substitute frozen berries for the fresh, and if you don’t have a lot of
time, this is a good option. Simply defrost the berries, and then mash them as
the recipe calls for. After defrosting, the berries will be in a lot of juice,
but don’t drain them–simply incorporate all of the juice into the mashed