Step 1

Fill a canning pot with water, set the lid in place, and heat on high heat until boiling. It can take awhile for the water to come to a boil, so get it started before you begin making the jam.

Step 2

Gather the jars you'll use, making sure each is clean and free of nicks in the rim, which could impede sealing.

Step 3

Bring a small pot of water to a simmer and turn off the heat. Drop the rings and lids into the water and leave them there until you're ready to screw them onto the filled jars.

Step 4

Combine ½ teaspoon calcium powder (from the small packet in the box of Pomona’s pectin) with ½ cup water in a small jar.

Step 5

Screw on a lit and shake until well-combined. You'll have more than you need for this recipe.

Step 6

Store the excess in the refrigerator for use in making additional jam or jelly recipes.

Step 7

Measure the grape juice, lemon juice, and 4 teaspoons of prepared calcium water into a large saucepan; bring to a full rolling boil. (Save the remaining calcium water in the fridge for a future batch of jelly.)

Step 8

Meanwhile, combine the sweetener with the pectin until it's thoroughly combined.

Step 9

When the grape 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 jelly back to a boil. You can use your immersion blender to do this, if you have one. Otherwise, whisk vigorously.

Step 10

Remove from heat when the jelly boils.

Step 11

Ladle hot jam into quarter-pint, half-pint, or pint sized jars, leaving 1/4" head space. A canning funnel makes this easy.

Step 12

Wipe jar rims to remove any jam that may have spilled. A clean rim is essential to a good seal.

Step 13

Set jar lids in place. Screw bands on finger tight.

Step 14

Use a jar lifter to gently place jars into hot water in a canning pot equipped with a rack. 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 simmer and then set the timer.

Step 15

Process for 10 minutes 0-1,000 feet altitude; add an additional minute for every additional 1,000 feet in elevation.

Step 16

Remove jars from water using the jar lifter and transfer to a solid, towel-covered surface. Allow to cool for 24 hours.

Step 17

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).

Step 18

Remove rings and wash outsides of jars. Store in a cool, dry place.

Step 19

If you'll use the jelly within a month or so, you can just refrigerate it. In this case, you can fill the jars to within 1/4" of the top.

Step 20

To freeze, use straight-sided jars and only fill them 3/4 full to allow room for expansion when frozen.

Step 21

Screw on lid and allow to cool before placing jelly in the refrigerator or freezer.