The first jam I ever made was plum jam. There were two plum trees in the backyard of the house I was renting and I almost killed myself picking two hundred pounds of plums that year. The thing is, it wasn’t very good jam. As I remember, it was so rubbery you might have bounced it like a ball. But we all need to start somewhere, and I was proud of my first efforts.
This blackberry lime jam was the first good jam I ever made. I don’t use boxed pectin very often these days, but I always begin blackberry season by making a batch of this jam with Pomona’s Pectin. I do it for the love of nostalgia and because I’m grateful to my friend Margaret, who first encouraged me to make jam, convinced me there was nothing to be scared of, and told me about Pomona’s. She didn’t know she was creating a jam-making maniac.
Blackberry Lime Jam with Pomona’s Pectin
4 cups mashed blackberries with half of seeds removed (about 3 1/2 pounds to start)
zest of 3 limes, minced
1/4 cup lime juice
2 cups sugar
3 teaspoons Pomona’s calcium water
3 teaspoons Pomona’s pectin powder
About calcium water. Calcium water is an essential part of Pomona’s Pectin; it activates the pectin powder. The calcium water mix and the pectin powder are both contained in the Pomona’s Pectin box. The box insert explains how to prepare the calcium water before you make your jam. (Don’t worry, it’s easy!)
1. Sterilize your jars.
2. Rinse the blackberries only if necessary. If I’ve picked mine in a field far from any road — which I try to do — or if they’re organic berries from a known source, I don’t rinse them. Doing so waters them down. But if the berries have been subject to car exhaust or pesticides, by all means give them a good rinse.
3. Use a food mill to remove the seeds from half of the berries. Removing seeds is optional, but our California blackberries can be a little crunchy, so I’ve started to do this with all of my wild blackberry jams. To get the maximum pulp from my berries, I let the food mill sit over a bowl while I prepare my other ingredients. Every five minutes or so I scrape the bottom of the food mill with a small silicone spatula and give it another crank.
Important note about pectin! I’ve calculated and tested the amount of Pomona’s Pectin you’ll need for a batch of jam with half the seeds removed. If you include more seeds, you’ll need less pectin — only 2 teaspoons each of calcium water and pectin powder for a full-seed jam. The reverse is also true. If you remove all of the seeds, you’ll need more pectin. Experiment with the seeds if you like, but know that it will affect the set of your jam.
4. Gently mash the remaining berries. If you picked them ripe they’ll already be soft, so you won’t need to do much to them. You can use any number of good mashing tools but, as I’ve confessed a number of times, I like to use my own thoroughly washed paws. You’ll get messy, but you’ll also have the opportunity to pull out any stray stems or unripe bits. I always use my hands with blackberries I’ve picked myself, because they can be full knobby little surprises. (I hate to even mention it, but do be especially vigilant about stray thorns. I once found one of those.)
5. Zest the limes and finely mince the zest.
6. Squeeze the zested limes and set aside 1/4 cup of juice.
7. Measure the sugar into a bowl. Thoroughly mix the pectin powder into the sugar and set the bowl aside.
8. Add the strained blackberry pulp to the mashed blackberries, then measure 4 cups of the berry mixture into your jam pot.
9. Add the lime zest, lime juice, and calcium water to the berries in your jam pot. Bring the mixture to a boil.
10. Fold in the sugar with the pectin mixed in. Stir the mixture vigorously for 1-2 minutes to dissolve the pectin.
11. Return to the mixture to a boil and remove it from the heat.
12. Ladle the hot jam into your sterilized jars, leaving 1/4-inch head space. Process 10 minutes in a hot-water bath canner. Yields about 6 half pints.
More to come! Our blackberries were slow to arrive this year, but our everywhere bushes — the invasive but delicious Himalayan variety — are busting out with one of the best crops I’ve ever seen. Just this week I’ve picked fifteen pounds. This month I intend to post several blackberry jam recipes, including a basic blackberry jam sans pectin and a refined version of my blackberry mojito jam, with plenty of rum, lime, and mint. Stay tuned!
This jam won a ribbon at the 2010 Marin County Fair! You can find all of my ribbon-winning recipes in H2H Prizewinning Recipes 2010.