Seville Orange

A popular bitter Orange grown in the Northern California region. It has a thick, rough skin and an extremely tart, bitter flesh full of seeds. Because of its high acidic content, the Seville is not and eating orange but , because of that same acidity is extremely popular for making marmalades as well a liqueurs. Packed in 40-pound cartons.

Although the Seville orange's sweeter sisters may grace our shelves all year round, the Spanish fruit has all but disappeared by the end of February. Marmalade-makers await the season eagerly, while other people may not even be aware of its passing. This is largely because underneath the Seville's thick, rough skin, the flesh is extremely tart and packed with seeds; it is not an eating orange, but its high acidity offers perfect setting power for preserves.

Bitter oranges originated in the northeast of India and neighbouring areas of China and Southeast Asia. During the first centuries of their empire, the Romans took a great interest in the fruit; however, as their domination of Europe ended, so did the cultivation of oranges. By this time, Arabs had established both themselves and the bitter orange in Spain. With the Moors' irrigation technology, the fruit flourished in the once-dry land.

Some believe that the British passion for the fruit – or rather, the fruit transformed to marmalade – began with a happy accident in 1700, after a young Dundee grocer named James Keiller took a risk on a large consignment of oranges that were en route from Seville, on a ship sheltering against a storm in Dundee harbour. The oranges were cheap, but Keiller couldn't sell them: the flesh was far too sour. His shrewd wife, however, used the oranges to make a spreadable preserve. The jars went on sale in Keiller's shop and soon demand became so high, the family had to order a regular shipment of oranges from Seville. By 1797 they had opened Britain's first marmalade factory.

Despite the huge number of bitter oranges that are grown in Seville, none is available to buy in the shops or markets; the people of Seville can pick the fruit freely from the trees anyway, so there's little point trying to sell them. But the Spaniards use few in cooking and they aren't big marmalade-makers, so the bulk of the harvest is exported to Britain. That said, the sisters of the San Leandro and Santa Paula convents make bitter orange preserves, to traditional recipes that have been handed down the years, to be sold alongside their famous pastries.

Marmalade aside, the tart juice of the Seville orange can also be used to create tangy salad dressings and fabulous sauces to cut through the richness of meat and game. The classic French bigarade is a delicious example: a dark, port-enriched, orange-flavoured sauce that is traditionally served with roast duck and for which dessert oranges would prove far too sweet.

The juice makes a great alternative to lime or lemon juice in ceviche, a Latin American fish dish in which the citric acid has a similar effect to heat on the protein bonds in the tissue and 'cooks' it by marination. Firm white fish, plump meaty scallops and oily, omega-3-rich fish such as salmon and mackerel work especially well. Simply slice the fish thinly and marinate in a mixture of bitter orange juice, lightly seasoned with salt and freshly ground black pepper, with some sliced or chopped onion, crushed garlic, maybe a chopped chilli or two – even a grating of ginger. Leave in the fridge or another cool place for a couple of hours or so, until the flesh turns opaque – and that's all it takes. Just ensure the fish you are using is ultra-fresh.

To create versatile flavoured oils and vinegars, just drop a piece or two of oven-dried peel into the bottle and leave for a while to infuse. They will beautifully complement zingy, peppery leaves such as rocket, spinach and watercress.