A couple of years ago, my mother had four jostaberry plants sent to me for my birthday. If you know me, you’ll know that a fruit plant is always a wise gift to give me! What is a jostaberry, you ask? Well, if you want to get very specific here’s a link to its Wikipedia page, but for the most part it is a hybrid of black currant and two different gooseberries. It’s a hardy, disease resistant plant that yields large, dark purple berries. It’s got the tartness of the gooseberry and some of the complexity of a black currant.
This is the first year that I’ve had a significant harvest, considering last year’s was all of four berries. This year I’ve taken a few pounds already, and there are more hanging on the bush. I believe I am taking them well before they are ready–about a third are dark purple which is the ripe stage, a third are maroon with tinges of green, and a third are green because they just came off. Why haven’t you seen more jostaberries around? Well, I’ve found out first hand: they are hard to pick even though they do not have thorns like gooseberries do. I’m surprised it is said that birds will get them quickly, because the berries don’t seem to want to come off the stem. You really have to pull, hence all the green ones I’ve gotten. I’m going to let the rest of them get really dark and see what happens. As you may know, some unripe fruit is good for a jam. The levels of pectin are higher in unripe fruit, and therefore your “set” (or how firm a jam is) will be easier to reach.
I’m excited to experiment with this fruit, as it seems that they will do well in both sweet and savory applications (I’m thinking pickled jostaberries), but my predilections always run to jam first. My first batch was a real treat: deep garnet in hue, sweet and tart with a chewiness I appreciate. You can detect the black currant undertones, which I can only describe as a mix between deep forest and red berry. There are a few seeds in the berry which I don’t mind, but some may wish to pass it through a sieve. Today I might try a batch with a traditional gooseberry flavoring: the elderflower, which is blooming profusely all around my yard. For now these are the basics of this jam, if you see it at a market I hope you try it!
Yields two 8 ounce jars, plus a bit for the fridge
1 pound of jostaberries (about a quart), topped and tailed
1/2 pound of sugar (1 cup)
1/4 cup water
First, you must top and tail the fruit. I have heard you can leave them in, but the stems and dried flowers are rough and scratchy, so I prefer them off. What exactly does top and tail mean? On one end is the stem, and on the other end is the spent flower–take them both off. You can snip them with sharp scissors, but using your fingers seems just as quick. It’s sort of a pain, but find the zen spot of it.
Put the topped and tailed berries in a pot with 1/4 cup of water. Boil gently for ten minutes to soften the berries. Add the sugar, and return to a boil. The mixture will quickly turn magenta, deepen and start to form large glossy bubbles. It will take about ten minutes to reach the gel stage. If you boil it too long, you may end up with a very firm jam, which might be fine with you depending on your preferences. I use the spoon technique, and watch for two drips. It’s very unscientific, but I’ve found it’s the best indicator of a when jam is done, even more so than the cold plates method, which I find very fussy.
There is no need to add lemon, as the berries are very tart. You may process these in a boiling water bath for ten minutes to keep them on the shelf.