I’ve been thinking about wild blackberry jam. There’s nothing at all wrong with a basic approach: combining blackberries with sugar and lemon juice and cooking the mixture until it sets. You don’t need to add pectin, you can keep the volume of sugar relatively low, and you’ll get a fine result. (You can find some examples of this simple process in other posts on this blog: Blackberry Chambord Jam, Boysenberry Jam, and Tayberry Jam.) But blackberries have been bugging me, anyway.
They’re one of my favorite fruits, a summertime sine qua non. That means I want to love the jam as much as I love the blackberries themselves — but I don’t, quite. When I imagine wild blackberry jam, I want it to be luscious and soft, even though it still has some seeds. (I usually remove about half of them.) But the reality is usually a jam that’s a lot firmer and much more dry than my dream jam should be.
One way to change the texture of the jam would be to significantly increase the amount of sugar in the recipe, but I tried that and really couldn’t stand it. I decided to find out whether strawberries would work to smooth and plump up the texture, and I do like how it turned out. This jam is mostly blackberry, and it tastes that way, but the strawberries work a little bit of magic in the jar, enriching the flavor and easing the gritty tendencies of those wild California fruits.
Join me in the experiment, if it appeals to you . . .
Blackberry Strawberry Jam
3 pounds wild blackberries
1 pound strawberries
2.5 pounds sugar
4 tablespoons lemon juice
1. Sterilize your jars and put 5 teaspoons on a plate in the freezer, to test your jam for doneness later.
2. Carefully pick over the blackberries, removing any stray thorns or brambly bits. Rinse them only if necessary — that is, only if they’ve been sprayed or subject to vehicle exhaust. (Better to pick them in an unmolested spot far from the road.)
3. Rinse, hull, and roughly chop the strawberries (unless they are small to begin with, in which case you can leave them whole)
4. Combine the berries, sugar, and lemon juice in a large glass or ceramic bowl, cover tightly, and let rest in the refrigerator for up to 24 hours. (By allowing the fruit to macerate in this way, you’re creating a flavorful, pectin-rich juice while at the same time allowing the sugar to initiate the preserving process. It’s much better than letting those berries sit on their own in the fridge.)
5. When you’re ready to make the jam, transfer the contents of the bowl to your jam pan. Heat the mixture on medium, stirring frequently until the sugar is fully dissolved. Then turn up the heat and bring the mixture to a boil, stirring as needed to prevent sticking or burning. (If it really wants to stick, turn down the heat a bit.) Use a shallow, stainless-steel spoon to skim the stiff foam off the top of the mixture as it cooks. In my 11-quart copper jam pan, the total cooking time is about 25 minutes. Watch the mixture and test it when it starts to thicken up, the foam settles down, and the bubbles become small and shiny.
To test your jam for doneness: Remove the pan from the heat. Use one of your frozen spoons to scoop up a little bit of jam — not a whole spoonful. Return the spoon to the freezer and wait 3 minutes. Retrieve the spoon and hold it vertically. If the mixture just fails to run and is thick and gloppy when you push it with your finger, it’s done. If the jam isn’t ready, cook it a few minutes more.
6. When the jam is done, bring it back to the point where it just begins to boil and immediately remove it from the heat. Extract some of the seeds from the jam by quickly pressing 3-4 cups of the very hot mixture through a stainless steel sieve. I use the back of my wooden cooking spoon to work the jam through the sieve, holding it directly over the pot. (This entire step is optional; you can make fully seeded jam if you prefer. If you do remove some seeds, consider this: Instead of discarding them, you can toss those jammy leftovers into a quart jar with a few cups of vodka and an extra handful of sugar. Shake the jar once or twice a day and, ten days later — you’ll have blackberry strawberry liqueur.)
7. Ladle or pour the jam into sterilized jars, leaving 1/4-inch head space. Wipe the jar rims clean and secure the lids. Process 10 minutes in a hot-water bath canner.
Yields about 6 half pints.