24. Seville orange

My wife is a cook. She’s very good at it, and she enjoys it, which means I’m rarely called upon to do day-to-day cooking. Instead, I go for longer-term and more esoteric projects: pickling, preserving, steeping and infusing; the kind of cooking that is about turning seasonal gluts into a year of good eating. This blog began with me picking blackberries in late summer, which ended up in vinegars and crumbles and jams. In May, I will turn elderflowers into cordial. And each January, I make marmalade.

You can only make proper marmalade in January. That’s because it calls for the Seville orange, a citrus hybrid with a season that stretches for just a few weeks. In Europe, Seville oranges are a single-purpose fruit: they are too bitter to use for much other than marmalade-making. In this way, they tell a story, about how humans hunter-gatherers hung up their spears, picked up their ploughs, and turned a few unprepossessing wild plants into a bewildering array of crops.

Every citrus fruit we eat comes from just four wild species: Citrus reticulata (the true mandarin), Citrus maxima (the pummelo), Citrus medica (the citron), and Citrus micantha (the papeda). Clementines and oranges and lemons and limes and grapefruit are all hybrids of the first three, while yuzu, the Japanese ingredient du jour, is derived from a papeda.

Hybrids are a bit like a musical equalizer: over generations, you can mix in more or less of different species for different effects. This, broadly, is how we ended up with sweet oranges, rosy apples, plump strawberries, and sweet plums. It’s also why commercial wheat yields far more flour than any wild variety: over dozens of generations, we have bred the strains that feed us best. (You may enjoy this comparison of modern fruits and their wild counterparts.)

The truth is, most wild plants are a faff to eat, and opinion is divided on whether they would have provided enough energy density to feed early man. Hybrids made us human.

Which brings me back to the Seville orange. One we’d accomplished the basic task of making wild plants more nutritious, we started getting clever, and picky.

The reason you can make marmalade with it is the higher pectin content: most other jams require fortification with apples, or with commercial pectin. And whereas other plants would wilt under the fierce sun of southern Spain, Citrus × aurantium thrives. It’s a plant bred over centuries to occupy a very specific niche – the British appetite for a jam made from an all-but-inedible Spanish fruit, and a powder (sugar) shipped halfway across the world. If that doesn’t tell you anything about the wonder of human civilisation, I don’t know what will.


Marmalade recipe

I make my marmalade to a recipe from Bulletin 21 (Domestic Preservation of Fruit and Vegetables), first issued by the Ministry of Agriculture and Fisheries in 1933. It is my Bible, and as far as I’m concerned, it trumps any modern recipe book. I will write about it in more detail in a future post.

That said, all marmalade recipes are pretty much the same. Here’s a basic one. It calls for a sugar thermometer (they’re dead cheap), and the biggest pan you can lay your hands on.



  • 2kg Seville oranges
  • 4kg granulated sugar
  • 4.5 litres of water
  • Two lemons
  • A knob of butter



  1. Halve the oranges and lemons and juice them into a jam pan.
  2. Scoop the seeds and pith out and tie them up in a muslin bag.
  3. Cut the peel into thin strips.
  4. Add the water and peel to the juice, and dangle the muslin in. Boil for at least two hours, until the peer is tender and translucent. (You can pause at this stage for a day or two if you need.)
  5. Add the sugar, then heat the mixture while stirring continuously, until you hit a rolling boil. A creamy scum will start to form on the top. You can skim it off, or just ignore it.
  6. To create a firm marmalade, you need to be sure that all of the marmalade has hit jam temperature (105ºC – it will be marked on your thermometer). This can be tricky. The marmalade will normally get to around 100ºC then climb very slowly as the water boils off. Keep stirring, be patient. I tend to wait ‘til I’m getting a consistent reading of 106-107ºC. (Don’t go too high, though, or you’ll end up with a firm caramel.)
  7. Take the marmalade off the heat. Add a knob of butter and stir in to disperse the scum.
  8. Let the mixture cool for 15 minutes, then pour into sterilised jars. Fill them right to the top before sealing.

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