My mom and I have made this jam together for the past two years. We use Pomona's pectin because it works well with recipes that use less than the standard amount of sugar (typically 6 cups or more). Trust me--you won't miss the added sugar in this jam. And isn't 4 cups more than enough, anyway? You could probably even use a lot less than that and still have very tasty jam. The lemon balm is optional; it does add a little lemony brightness, but this would be great raspberry jam even without it.
Yield: approx. seven 8-oz jars, with a little left over
5 half-pint baskets of raspberries (we used a mix of red and golden raspberries)
4 c. sugar, divided
1 t. butter
3 t. Pomona’s Universal Pectin
3 t. Pomona’s calcium water (calcium powder is included with Pomona’s pectin; instructions are in the box)
1 bunch lemon balm (optional)
Sort out any stems, leaves, and mushy or moldy berries. Crush the berries in a large pot (a potato masher works well). You want them fairly uniformly crushed but not lumpless. Add the butter and calcium water to the berries. Mix ¼ c. of the sugar with the 3 t. pectin and add to the berries. Tie lemon balm with string and place in mixture. Bring mixture to a full boil over high heat, stirring often. When mixture is at a full boil (one that cannot be stirred away), quickly stir in the remaining 3 ¾ c. sugar. Return mixture to a full rolling boil and continue boiling for 1 minute, stirring constantly. Remove from heat and test to see if the jam is setting properly (see below). Remove lemon balm. Skim off foam if necessary. Ladle jam quickly into sterilized jars (see below), filling to within ¼-inch of tops. Wipe jar rims and threads to remove any jam remnants. Cover jars with hot lids (see below) and rings. Tighten rings (not too tight). Place jars in canning rack. Lower rack into canning pot filled about half-full with almost-boiling water (you'll need more water if you're using large jars). Top off with hot water if necessary to bring water level 1 to 2 inches above jar tops. Start timing when water comes to a boil. Remove canning rack full of jars after about 5 minutes (10 minutes max). Place jars on a towel to cool. After a couple minutes, press the center of each lid to check for a true seal. The lid should not flex at all in the center if you’ve got a true seal.
To test if the cooked jam is setting properly: Put a metal spoon in a glass of ice water. When the spoon is cold, use it to scoop up a little of the cooked jam. Let that sit for a minute and then check if it seems set to a jam-like consistency. If not, add more pectin to the jam and bring to a boil again.
A note on jars: Avoid 4-ounce jars, because they tend to fall out of the canning rack. It’s also best to use a uniform jar size.
To heat lids: Place lids in a pan of hot water over low heat. Do not let the water come to a boil. The point is to help the sealing compound get soft and gummy.
This jam is delicious.