Prepare the calcium water:Combine ½ teaspoon calcium powder (from the small packet in the box of Pomona’s pectin) with ½ cup water in a small jar. Screw on a lit and shake until well-combined. You'll have more than you need for this recipe. Store the excess in the refrigerator for use in making additional jam or jelly recipes.
Wash the jars you'll use, making sure each is clean and free of nicks in the rim, which could impede sealing.
Wash the lids and rings in hot soapy water. (If you're using non-Ball brand lids, prepare as suggested by manufacturer.)
Place empty jars in a canning pot or large stock pot with enough water to cover by an inch or two, cover pot, and set on high heat. It can take awhile for the water to heat, so get it started before you begin making the recipe.
MAKE THE RHUBARB JAM
Wash and trim the rhubarb stalks. Cut into 1/2” chunks and place chopped rhubarb into a saucepan with 1 cup of water. Simmer until rhubarb is soft. Use a potato masher to mash the fruit mixture or for a finer jam, use an immersion blender.
4 cups cooked rhubarb
Tie cardamom pods into a piece of cheesecloth.
1 tablespoon whole cardamom pods
Measure 4 cups of the prepared rhubarb, lemon juice, orange zest, ginger, prepared cardamom, and calcium water into a large saucepan; bring to a boil.
Meanwhile, combine the sugar with the pectin until it's thoroughly combined.
2 cups sugar, 3 teaspoons pectin
When the rhubarb mixture comes to a boil, stir in the pectin and sweetener, stirring vigorously for 1 to 2 minutes to dissolve the pectin while bringing the jam back to a boil. Remove from heat when the jam boils.
CANNING THE JAM
Remove empty jars from canner, draining water back into pot.
Ladle hot jam into quarter-pint, half-pint, or pint sized jars, leaving 1/4" head space. A canning funnel makes this easy.
Wipe jar rims to remove any jam that may have spilled. A clean rim is essential to a good seal.
Set jar lids in place. Screw bands on finger tight.
Use a jar lifter to gently submerge jars into hot water in the canning pot. Water should cover the top of the jars by an inch. The water will cool somewhat in reaction to the addition of the jars. Return the water to a boil and then set the timer.
Process for 10 minutes 0-1,000 feet altitude; add an additional minute for every additional 1,000 feet in elevation.
Remove jars from water using the jar lifter and transfer to a solid, towel-covered surface. Allow to cool for 24 hours.
Check seals. Lids should be solid and pulled down tight. (if they flex and pop, the jar didn’t seal; put unsealed jars in the refrigerator and use those first).
Remove rings and wash outsides of jars. Store in a cool, dry place.
Notes
SOURCE: Adapted from guidelines provided by Pomona's Universal Pectin.
This recipe is made using Pomona’s Universal Pectin. This is the only pectin I use anymore as it allows me to use much less sweetener. The standard pectin brands use an obscene amount of sugar in my opinion, often requiring equal amounts of sugar and fruit! This product uses a low methoxyl method and calls for using two different ingredients, which are included in the box: pectin (the large packet) and calcium powder (the small packet).
This recipe calls for using cardamom pods, freshly grated ginger, and orange zest to make a spiced rhubarb ginger jam. If you want a plain rhubarb jam, it is safe to omit the spices.
Store opened jars of home made jam in the fridge for up to a month.
Boiling lids or heating above 180°F as once recommended can damage the sealing compound.
To make rhubarb freezer jam:
Prepare jam as directed. Transfer jam to jars leaving sufficient headspace for expansion during freezing. Use your favorite freezer containers or glass jars. Go here for tips on safely freezing in canning jars. Store for up to six months. Thaw in the refrigerator to use.