Once upon a time, so long ago that she has no doubt long forgotten it by now, a lady named Alianore expressed interest in a recipe for raspberry jam. This summer is the first season since then that I’ve made raspberry jam, as I don’t usually have surplus raspberries for preserving (thanks to the local blackbirds).
The lemon juice contains pectin which helps the jam to set, and also adds a slightly sharp flavour to the finished jam. I like the sharp flavour, but if you don’t, you could use commercial pectin instead of lemon juice. I’ve never used commercial pectin so I can’t give you any advice, but the instructions on the packet should tell you how to use it. If you don’t use either lemon juice or commercial pectin, raspberry jam can take for ever to reach setting point, and this is usually a Very Bad Thing as long boiling tends to result in a rather dark and excessively sticky jam. So I strongly recommend you add pectin in some form or other.
All the books tell you to use perfect and slightly under-ripe fruit for preserving. I am sure they are right. However, I tend to use jam as a repository for the berries that get squashed during picking and transit, and I can confirm they work perfectly well in this recipe (but see above for the importance of adding pectin in some form).
Here’s the recipe.
1 lb (approx 450 g) raspberries
1 lb (approx 450 g) granulated sugar
Juice of half a lemon
Remove the stalks from the raspberries and check that the fruit is in good condition. A bit squashed is OK.
Put the fruit and lemon juice in a large saucepan. If liked, you can add the lemon zest as well.
Heat gently for a few minutes until the juice starts to come out of the raspberries.
Add the sugar and a small piece of butter (about the size of a hazelnut), and stir until the sugar has dissolved.
Bring to the boil. Don’t lean over the pan and keep any children or pets out of the way. Boiling jam will sometimes spit, and as it is both hot and sticky it can give an unpleasant burn.
Boil at a full rolling boil – this means lots of bubbles across the whole surface of the liquid – until setting point is reached. To test for setting point, scoop out a teaspoonful of jam and drip it onto a cold plate. It will form a pool. (If it forms a bead, your jam is ready – take it off the heat straight away and proceed to the next step). Wait for the pool to cool (30 seconds or so), then push it horizontally with your finger. If the surface wrinkles, the jam is ready. If the pool stays liquid, keep boiling for another 2 minutes and test again. I usually find this jam reaches setting point after about 10 minutes boiling.
(I am told that a sugar thermometer makes it easier to recognise setting point. I’ve never used one, so can’t comment. The old-fashioned way works for me.)
Remove the jam from the heat, and pour into clean glass jars. I find the easiest way to do this is to pour from the pan into a heatproof jug, then use the jug to fill the jars.
Seal the jars immediately. I seal jam jars with a layer of cling film and then a screw-top lid, but you can use any method of your choice as long as it is air-tight.
Let the jars cool, label them, and store in a cupboard until needed. It doesn’t need to mature so you can start eating it the following morning if you like.
This quantity makes about 1.5 lb of jam (two medium-sized jars). You can scale it up as you see fit, but remember that you need plenty of space in the pan for the jam to boil without boiling over. If the pan is about half-full after you put the sugar in, that should be about right.