Beetroots are notable for their sweetness, they have the highest sugar content of any vegetable, but they are very low in calories. Fresh beetroot also supplies a nutritional bonus, their green tops are an excellent source of beta-carotene, calcium, and iron.

They belong to the botanical species Beta vulgaris, which also includes sugar beets (which are processed for sugar), mangel-wurzels (very large roots used as animal fodder), foliage beets, and Swiss chard (the latter two grown for their greens, not their roots). All these vegetables are descended from a wild slender-rooted plant that grew abundantly in southern Europe. In ancient civilisations, only the green leaves of the beet plant were eaten; the roots, which did not look like modern beets, were used medicinally to treat headaches and toothaches. Beets with good-sized, rounded roots, like those we eat today, were probably developed in the sixteenth century, though it took another 200 years before they gained any popularity as a food.

Buying
Beets are marketed in a range of sizes. Early crop beets are usually sold in bunches with the tops attached, or as clip-topped beets in perforated plastic bags. If those you buy are bunched, choose equal-sized ones so that they will cook evenly. Very small "baby" beets, golf ball sized immature roots that have been pulled to thin the farmer's rows are particularly good. Medium-size beets are fine for most cooking purposes, but very large specimens (over 2 1/2" in diameter) may be tough, with unpalatable woody cores.

Look for smooth, hard, round beets; a healthy deep red color is an indicator of quality. The surface should be unbruised and free of cuts. Avoid beets with soft, moist spots or shriveled, flabby skin. The taproot, which extends from the bulbous part of the beet, should be slender.

If the leaves are attached, and especially if you're planning to eat them, it's preferable that they be small, crisp, and dark green. Leaves that are larger than about 8" are probably too mature to be palatable. Limp, yellowed leaves have lost their nutritional value. However, beets with wilted greens may still be acceptable, because the leaves deteriorate much more quickly than the roots. If the leaves on the beets offered at your market look less than fresh, be sure to check the roots extra carefully for soundness. If the beets are clip-topped, at least 1/2" of the stems (and 2" of the taproot) should remain, or the color will bleed from the beets as they cook.

Storage
To reduce moisture loss from the roots, cut off beet greens before storing, but leave at least 1" of the stem attached (tiny leaf-topped baby beets can be stored for a day or two with their tops intact). Place the unwashed roots in a plastic bag and store in the refrigerator salad drawer for up to three weeks. Store the greens separately in the same fashion and use them as soon as possible; they are perishable and will keep for only a few days.

Preparation
Generally speaking, to preserve their colour and nutrients, beets should never be cut or peeled before cooking them in liquid; otherwise, they will "bleed" their rich red juices while cooking and turn an unappetising dull brown. Scrub the beets very gently and rinse well, but be careful not to break the skin, which is quite thin. Leave at least 1" of stem and don't trim the root.

Beets are done when you can easily pierce them with the tip of a sharp knife. Once cooked, you can peel them; the skin of a cooked beet will slip right off. (However, it's wise to use a paper towel or wear gloves to keep the beet juice from staining your hands.) Then cut the beet in quarters, slices, cubes, or in long, thin strip or, if they're small, serve whole.

Cooked beets hold their colour better if some acid ingredient is added to the cooking water; vinegar or lemon juice, used in many beet recipes, will keep them a beautiful crimson.