If I had £1 for everyone who’s asked me what a jostaberry is, I’d have … well, at least £5 by now. For those who don’t already know, a jostaberry is a cross between a blackcurrant and a gooseberry. The fruit is half-way in size between the two and tastes like both. The plant itself is extremely vigorous and productive, is thornless, and is resistant to most of the diseases blackcurrants are prone to, although it can suffer from gooseberry saw fly and jostaberry leaf netting. I’ve been growing a jostaberry for years (you only need the one) and I don’t understand why everyone doesn’t grow it because it’s the mainstay of my late summer jam-making. The fruit, like both parents, is high in pectin so it makes brilliant jams and jellies and, being subtler in flavour than a blackcurrant, is a useful addition to fruit that’s low in pectin, such as blackberries. The one disadvantage is that, like gooseberries, you need to top and tail jostaberries. But the fruit tends to come away without any stalk (so no tailing) and if you open-freeze the berries the flower ends are easy to nip off while still frozen. So, having extolled its virtues, here is my recipe for jostaberry jam:
1 kg jostaberries topped and tailed, 600 ml water, 1 kg sugar. Cook the jostaberries with the water until skins are soft (30-45 mins). Add the sugar, stir until dissolved and bring to a rolling boil. Boil hard until a set is reached – anything from 5 to 15 mins. Test by dropping a little onto saucer chilled in the freezer. Leave for a couple of minutes and push with your finger. If it wrinkles it’s ready to pour into the jars. For blackberry jam I use about 4 parts blackberries to 1 part jostaberries but I cook the jostaberries (1 litre water per kg) for at least 30mins before adding the blackberries. Then I make the jam as above, using 1 kg sugar for 1 kg total fruit.
Of course making jam isn’t the only way to preserve stuff and one of my regular ‘preserves’ is tarragon vinegar. One batch provides a year of salad dressings. Sterilise a tall wide-necked bottle in the oven. Cut enough tarragon stems to loosely pack the bottle. Wash the tarragon to remove beasties and spin it dry. Measure a bottle-full of cider or white wine vinegar (not distilled!) and heat it so that it’s almost boiling. Pour over the tarragon in the jar, cool, cover and leave for about a month. Then strain and bottle into clean bottles. I keep mine for up to a year, although it will throw a deposit by then. Tarragon jelly is another great way of using tarragon. It’s basically an apple jelly with a large bunch of tarragon boiled with the juice for about 15 mins then removed before the sugar is added. It’s wonderful with roast chicken.
Raspberry Gin – this isn’t strictly speaking a preserve but it makes a regular appearance in my ‘still-room’ (a shelf in a cupboard). You can make it at any time of year if you’ve frozen some of your raspberries. I’m growing autumn fruiting raspberries and they are only just beginning to produce a small amount of fruit so I’ve earmarked these for raspberry gin. Take 250 g raspberries, fresh or frozen, add 50g sugar and 500 ml gin. Seal tightly and give it a shake every day until the sugar has dissolved. Keep in the dark for about a month then strain into a clean bottle. Looks great and tastes great, either neat or with tonic and ice. This year I’m going to try it with some of my foraged blackberries. If it works it will be one of my low-carbon Christmas presents, a subject I hope to cover in a later blog. So watch this space ….!