My breakfast this morning – Davidson Plum jam on multigrain sourdough toast. Mmmmm
Davidson plums (and kumquats) are just about the only fruit I turn into jam. Mulberries, mangos, peaches, strawberries to my taste are better as not-jam – just very lightly stewed fruit without added sugar, for eating fresh, spread on toast or pancakes or scones.
But fresh Davidson plums are mouth puckeringly sour, and with a jam quantity of sugar they turn into something so memorably good that white-sugar-is-poison doesn’t apply. They’re a rainforest understory plant native to my part of the world. We’ve planted lots of them in the riparian regeneration project I’ve been working in for the last decade. My reward is in – a walk through the rainforest and kilos of Davidson plums.
They make very easy and very superb jam – enough pectin to set reliably without anything added, just two largish easy to remove seeds, a full complex flavour that would be overelaborated by adding spices, and a gorgeous deep clear claret colour.
- Put some jars and their lids on to sterilize by pressure cooking for 5 minutes or boiling for 15. The sugar in jam preserves it from nasty bacteria but sterilizing the jars stops it going mouldy on top if stored for long. Yes, well, maybe we don’t need to worry about that.
- Put a flat plate in the fridge or freezer to cool.
- Remove the two seeds in the fruit. I find this easiest to do by just squishing them and feeling for the seeds. (If they are not ripe enough to squish, they aren’t ripe yet. They should be a deep purple colour and softish.)
- Weigh them, and add an equal weight of white sugar. There are not many situations where white sugar is called for, but that beautiful deep clear colour in the finished jam calls for it. The jam will work with raw sugar but it will lose that jewel brightness. Don’t skimp on the sugar – it’s not there just for sweetness. Reduce the sugar and you have to boil the jam long enough to reduce the fruit juice before it will set.
- Add the juice and pulp (but not the seeds or skin) of half a lemon for each kilo of plums. The pulp has pectin that helps jam set.
- You need a non-reactive pot – the plums are acidic enough to draw a metallic taste out of iron or aluminium. Use stainless steel, enamel, or pyrex.
- Half way through the cooking, when the plums have softened, I use an eggbeater to break them up a bit.
- Keep at a nice steady soft boil, stirring occasionally to stop it sticking, till it turns to jam. How do you tell? Take a teaspoonful out every so often and test it on the cold plate. (Be careful not to take it too far or it turns to toffee – it stiffens up as it cools.) How long it will take to turn depends on the juiciness of the fruit and the pectin level. This batch took about 20 minutes, but I have had it take up to an hour.
- Put a ladle in the jam pot so that it is sterile too. Carefully, carefully (hot jam is one of the worst kinds of burns) ladle the jam into hot jars. Wipe the rim with a clean cloth or paper and put the lids on straight away.