It’s the season for blood oranges. Here’s how to make the most of them

Blood oranges can take you by surprise. In 1988, a Californian woman named Merleen Smith became convinced that her neighbour was poisoning the Valencia orange tree in her backyard. Smith could not understand why the flesh of her oranges, which had always grown orange before, was now a shocking dark red. She reported the neighbour’s crime to the local farm adviser, who suspected something else was going on. After analysing a sample, plant researchers confirmed that Smith’s tree had spontaneously mutated into a new form of sweet blood orange, now known as the Smith Red Valencia.

It isn’t hard to see why Merleen Smith might have been shocked at the sight of blood oranges. Compared to an ordinary orange, they are so luridly and gloriously red (although the peel is often deceptively orange). “Oranges soaked in sunsets” is how they were described by the Italian writer Carlo Emilio Gadda. Their deep colour has given them a new cachet in this age of Instagram. Dried blood orange slices have become the cocktail garnish of choice, and a glowingly beautiful blood orange and olive oil cake was the cover image on Dessert Person by Claire Saffitz, which was one of the cookbook bestsellers of 2020 in the US. Saffitz’s blood orange cake — a simple upside-down cake in which many overlapping slices of the fruit are made still redder with a mixture of blood orange juice and sugar — has been much imitated but not yet bettered.

But the real surprise of a blood orange is that however exciting the colour may be, the flavour is even more so (or at least it can be, if you get a good one). Sometimes they are called “raspberry oranges”, an apt name. There is something perfumed and almost winey about them, which makes them one of the great citrus treats of this part of the year (Sicilian blood oranges are in peak season from January to April, a time when so much other fruit is uninspired — too late for apples and too early for berries). Their flavour is more complex than an ordinary orange. The first written description of a blood orange in Italy comes from a book on citrus fruit by Giovanni Battista Ferrari published in 1646. Ferrari referred to a purple-fleshed orange with a grapelike flavour which had travelled from China to Sicily.

Sicily is still the great home of blood oranges and the reason for this is climate. One blood orange grower on the island told fruit expert David Karp, “You can take this orange — bloody, bloody, bloody — and plant it only 10 kilometres away . . . but you may well get no red fruit at all.” What makes an orange bloody is not heat but cold. The red of a blood orange, as well as its berrylike taste, is due to chemicals called anthocyanins, which are also found in other deep-coloured fruits such as blackcurrants and blueberries.

These anthocyanins are only triggered in most varieties when the night-time temperature is at least 10C cooler than the day time during autumn and winter. Hence the fact that they grow so well at the foot of Mount Etna, where autumn temperatures drop sharply at night. By contrast, in hotter citrus-growing regions such as Florida, growers have only succeeded in growing blood oranges consistently by using new varieties such as Ruby Valencia.

Italians recognise that the princes of all oranges are the arancia rossa of Sicily. First in the season comes the Moro variety, from December to February. This is the darkest blood orange: bloody on the rind as well as inside (unlike the Sanguinello, which is streakier) and much-used for making a wine-dark juice, although sometimes it can be excessively sour, with slightly musty notes. The supreme Italian blood orange is the Tarocco, which is harvested from January to May. In her lovely ode to Italian citrus, The Land Where Lemons Grow, writer Helena Attlee praises the Tarocco for its “meltingly soft flesh” and a flavour that “unfolds slowly, subtly, beguilingly”. Apart from their magical flavour, blood oranges also have health benefits. The Tarocco, for instance, is higher in vitamin C than any other citrus fruit, and rodent studies suggest that drinking blood orange juice appears to limit weight gain compared to juice from ordinary oranges.

So how are blood oranges best eaten? The season is short enough that it almost seems a waste to have them any way except just as they are, juices staining your hand, Lady Macbeth-style. Then again, a caramelised blood orange can be very pleasing. In Sicily, cooks slice them thinly into a salad along with olive oil, fennel and salt. Vinegar is redundant because the orange itself provides both sweetness and acidity, but a milky mozzarella is a good addition. I’m also fond of a Lucas Hollweg dessert, from his book Good Things to Eat, consisting of a lemon posset served with a compote of blood oranges made with caramelised sugar and a pinch of cinnamon. Against the pale posset, the blood oranges cannot fail to excite. They look like fire but taste like spring.

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