the cooking time may also affect the set – and that varies wildly among recipes, from 4 minutes from Jamie to a rather more dedicated 3 days from Thane Prince. The recipe in her book Jams and Chutneys is credited to her friend Sue, and requires the cook to macerate the fruit, sugar and lemon juice for 24 hours, before bringing the mixture to the boil and simmering it gently for 5 minutes. It's then left to mature in the pan for a couple of days, before being reheated and cooked until set to the cook's satisfaction – "the jam will always be quite soft, so I boil it until it thickens to my liking" Thane says. (Incidentally, Christine Ferber, la fée des confitures or jam fairy of Alsace, uses a similar method – and her jam is swooned over by the likes of Alain Ducasse.)
I'm expecting something spectacular, but although the results are certainly rich in flavour, the dark jam isn't as bright and fresh as, say, the Ballymaloe version: it's a sophisticated, grown-up take on what, in my opinion, should be a simpler pleasure. Although the hour's simmering advocated by the Preserved boys does help thicken the jam, it also leaves it with a slightly caramelised flavour – the 15 minutes suggested by Ballymaloe seems perfect: long enough to set the jam without robbing it of all freshness.