18.1 Berries and citrus

Berries

Berries are small and juicy, with thin skins and lots of seeds, often too tiny to notice. They grow on bushes and vines all over the world. The kitchen group does not match botany exactly: raspberries and strawberries are not true berries, while bananas and grapes are, though they are sorted elsewhere.

Berries stop ripening the moment they are picked, so they must ripen fully on the plant. When you buy them:

• Choose plump berries with full color.
• Pass over any box stained with juice, and any berries with gray-white or black spots of mold.
• Keep every kind of berry in the refrigerator and use it soon.
• Wash berries only just before you need them. Water takes away some of their aroma and makes them soft.

Berries are good eaten plain, and they go into breads, soups and sorbets. They make especially good jams and compotes.

• Blackberries look like large, glossy raspberries, deep purple to black. Their thorny vines grow wild in many places, and few are farmed. Loganberries, Marionberries, olallieberries and boysenberries are all crosses of the blackberry.
• Blueberries are small and firm, blue to nearly black outside and gray-blue and juicy inside. Farmed high-bush berries are usually bigger than wild low-bush ones. They come from North America, and their season is short: mid-June to mid-August.
• Cranberries are firm, sour berries with a blotchy red skin, grown on low vines in bogs. People seldom eat them raw. They go into sauce, relish, breads, pies and pastries, and they are easy to find frozen or as canned jelly sauce. Color does not tell you if a cranberry is ripe, so sort through them before cooking and throw out soft or bruised ones.
• Currants are tiny, sour berries that hang in bunches like grapes. Red ones are the most common; black and golden (white) kinds exist too. Every kind goes into jams, jellies and sauces. Black currants also flavor a liqueur, crème de cassis. The dried "currants" sold for baking are not these berries but a kind of dried grape.
• Raspberries may be the most fragile fruit of all, tart and velvety. A ripe one slips easily off its white core and leaves a hollow in the middle. Red is most common; black, purple and golden kinds are also sold. They crush easily and go moldy fast, so most of the crop is sold frozen.
• Strawberries are bright red and heart-shaped. The tiny black seeds on the outside, called achenes, are in fact the plant's true fruits. Pick berries with good red color and a green leafy cap (the hull) still on; a paring knife lifts the hull out. Avoid soft or brown spots. Very large berries look good but are often hollow, with little juice or flavor.
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Citrus

Citrus fruits include lemons, limes, oranges, grapefruits, tangerines, kumquats and several crosses. Each has a thick rind. Most of the rind is a bitter white layer called the pith, or albedo. Over it lies a thin colored skin called the zest. Inside, the flesh is juicy and divided into segments. Citrus is acidic and strongly scented, and it can taste bitter, sour or sweet.

Like berries, citrus fruits ripen fully on the tree and do not ripen any more once picked. Keep them in the refrigerator for the longest life. Choose fruit that feels heavy for its size, with a thin, smooth skin. Avoid fruit with big marks or damp spots.

• Lemons are the citrus cooks reach for most. They are too sour to eat raw, which makes them ideal for flavoring desserts and sweets. The juice goes into many sauces, above all for fish, shellfish and poultry, and the zest is candied or used as a garnish. A useful trick: rub a sugar cube hard over the peel of any citrus fruit. The sugar pulls out much of the scented oil, and you can then crush or dissolve the cube into a recipe.
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• Limes are small, with thin skins from yellow-green to dark green. They are too sour to eat raw and often stand in for lemons. They are juiced, or used in cocktails, curries and desserts, and grated lime zest adds color and flavor. The key lime is a small, sour lime from South Florida, the base of key lime pie.
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• Oranges can be sweet or bitter. Valencia and navel (a seedless kind) are the best-known sweet oranges. Use the juice for drinks and sauces, and the flesh raw, in salads, in cooked desserts or as a garnish; grate or cut the zest into thin strips for sauces and garnish. Pick plump, heavy fruit with clean skin. A green rind is no problem: skin color depends on the weather and does not change the flavor inside.
• Blood oranges are small sweet oranges with a rough, reddish skin and flesh streaked deep red. They are mostly a winter fruit, eaten raw, juiced, or used in salads and sauces.
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• Bitter oranges, such as the Seville and the bergamot, are grown mainly for the oils in their zest. Bergamot oil flavors Earl Grey tea. Seville oil goes into orange liqueurs such as curaçao, and into orange flower water, and Seville oranges are made into marmalade and into sauces for meat and poultry.
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• Grapefruits are large, round and yellow, with a thick rind and sour flesh. They began in the 18th century as a cross between the orange and the pummelo. White-fleshed grapefruit gives the best juice; pink or ruby grapefruit is sweeter. Grapefruit is best raw, or sprinkled with brown sugar and broiled for a short time.
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• Tangerines, also called mandarins, are small and dark orange. The loose rind peels away easily from sweet, juicy, fragrant segments. They are mostly eaten raw, and canned ones are sold as mandarin oranges. Tangelos are a tangerine and grapefruit cross, about the size of a medium orange, with a swollen stem end and few or no seeds.
• Kumquats are tiny, oval and orange. The skin is soft and sweet and the flesh a little bitter, so you can eat them whole, raw or kept in syrup. They also go into jams and preserves.
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For the knife work of sectioning a grapefruit or taking off zest, see the earlier chapter on knife work. see chapter 4: Techniques for particular foods