Bottled Light

If you buy, forage or find a boxful of ripe plums, greengages, blackberries or cherries, their taut skins full to bursting of the warm south, then the first thing you should do is sit at an outside table and eat them, greedily and alone, with sticky chin and stained fingers, until you feel nearly ill; this is the appropriate response to abundance. The next thing you should do, though, is make jam. I’m not really a fan of half-cooked fruit, soggying cakes, hanging around with pancakes and meringues. The ripest of raw materials loses a lot of itself when just partially cooked (think of miserable grilled tomatoes), regaining its isness only through thorough boiling; the fact that you can keep the product long into the winter is a definite bonus, although it takes a certain amount of self-restraint.
I always find raspberry and strawberry jams a little too frivolous. Blackberries, if you find them wild (and if you don’t, you have more money than sense), should more properly be made into a jelly, unless you like picking the woody pips out of your teeth all morning; a spreadable jelly, that is, not a wibble-wobble one – although that would also be an option. Clear, jewelled jellies are a fine thing, but take a little more investment of time and equipment than a simple jam, for which the best starting point is the fat, fleshy stone fruit of later summer and early autumn, with their complexities of sweet-sour juice and bitter almond, all of which can be played up, down or with in the cooking process.
I must have read a hundred recipes for jam, often lengthy and enlivened with rose petals or various boozes, which is ridiculous when you consider that there is really only need for one, which could be expressed as a haiku –
weigh prepared ripe fruit,
an equal weight of sugar,
cook, add sugar, boil –
although I suppose recipe writers need to make a crust somehow. Where else would they spread their jam? If you are entering a WI competition or are very fussy about your set, you might need to follow particular recipes or at least guidelines for different kinds of fruit; if you stick to stone fruit, and add a couple of lemons to help the pectin along, though, you should be fine, although I suppose there are a few extra guidelines I normally follow.
I stress prepared fruit, as the stones (especially if you are decadently making peach jam) add quite a bit to the weight. Don’t believe recipes that tell you to skim the stones off during cooking, either – it is a nightmare without end. Always cook the fruit to the consistency you want before adding the sugar, which seems to stiffen them; the slow cooking needed to bring them back to softness will caramelise the sugar, introducing a taste you don’t want – unless you do, in which case ignore this advice. A few well-chosen spices, added with the fruit, can really lift a jam. Don’t just reach for the vanilla pods; Vanilla Is Not A Universal Seasoning (a rule to live, or at least make dessert, by there), and in any case its heady sweetness isn’t really what you want in something so sugary. A star of anise adds a lovely boiled-sweet note to a simple plum jam, but in general I like to add ‘savoury’ spices – peppercorns, cloves, bay and cardamom all contribute a tiny bitterness to the mix. Put in a pinch of salt too, as you should with everything.
Setting point, assuming you have cooked the fruit enough and your proportions were correct, is 108°C. It’s useful, if you have a probe thermometer, to use it alongside the plate test or that thing with the spoon, as one day the battery to your probe thermometer will run out or rust, and you will never buy another. I can never remember how to do that thing with the spoon, but the plate test is easy. Before you start cooking, put a plate in the fridge, then, when you think the jam might be ready, turn off the heat and put a spoonful onto the cold plate. Let it cool and poke it. If it jellifies, wrinkles, and otherwise looks like jam, it is ready; if not, cook for a bit longer and keep testing. Resist the urge to try the hot jam. I forgot to say you should be cooking in a really big pan – if you didn’t, it will probably have boiled over, ruining your hobs and possibly badly burning you, so make sure you do.
The jam should be bottled while hot, a process which again requires a certain amount of care and attention. I suppose once you have poured boiling jam over your foot you will, for one reason or another, never do it again. Of course you should sterilise your jars in some fashion, but if you don’t, just keep the jam in the fridge – although this would be a shame, as jams, jellies and cordials should all really be stored where the winter light can stream through them, casting stained-glass shadows on the kitchen floor.