One of the best-known citrus fruits, oranges aren't necessarily orange - some varieties are yellow or dotted with red. Types fall into one of two categories - sweet or bitter.
Sweet varieties of orange include the Navel orange, which is named after the navel-like bulge at one end, which contains a tiny, baby fruit. They are seedless, easy to peel, and have a juicy, sweet flesh. Valencia have smooth, thin skins, with very few pips, and are particularly juicy. The skins of blood oranges are tinged with red, and the flesh ranges from golden to a deep ruby - they are juicy and aromatic.
The most well-known bitter orange is the Seville, only around for a few weeks in January. They are too sour to eat raw, but are great for marmalades or cooking with, and have a rough skin.
Various types ripen at different times, so there's year-round availability imported from outside the UK.
Choose the best
Look for unblemished, firm oranges that feel heavy for their size, as they're likely to be juiciest. The rind should look thin and fit tightly - if it doesn't it indicates that it might have a more than usually high level of pith.
Avoid those with any mould or soft spots. Rough, brownish patches (known as russeting) on the skin don't necessarily affect quality.
To juice oranges, halve and use a lemon squeezer. For zesting, the best oranges to use are unwaxed or organic. If you can't find either, scrub the skin well, then use a grater or zester, being careful not to grate down to the pith, which is bitter.
To pare and cut into segments, cut a little from the top and bottom of the orange and then, using a small, sharp knife, cut off the peel in a circular motion (as you would peel an apple), avoiding the flesh.
Alternatively, sit it on a board and cut in downward strokes, following the curve of the orange, working your way round until all the peel is removed. Then, holding the orange over a bowl to catch the juice, cut free each segment by slicing between the membranes to release it from the central core of pith.
Oranges keep for two weeks maximum, either at room temperature or in the fridge.
Add segments to salads or a jug of Pimms or sangria. Use the zest and juice for baking, sauces or marinades. Use when cooking game, chicken or fish. Squeeze the juice for breakfast.
Try clementine, tangerine or lemon.