The world's favourite root vegetable, the potato comes in innumerable varieties. A member of the nightshade family, like tomatoes and aubergines, it originated in South America and has been grown in Europe since the 16th century.
Shapes vary from small ('finger') potatoes like Anya to large, round types like the King Edward. Most have pale brown skins and cream or yellow flesh, but some speciality varieties are differently coloured, like the Purple Peruvian.
'Waxy' potatoes such as Charlotte are great used in salads, while 'floury' potatoes such as Maris Piper are ideal for mash and baking.
Choose the best
Look for firm, blemish-free potatoes. Avoid those that are cracked, have sprouts, wrinkles or green tinges. The fine, filmy skin of new potatoes can rub off, but other potatoes should have no bald patches.
Choose your potato according to how you want to cook it.
Older potatoes should be scrubbed well in cold water, and any eyes should be dug out with the tip of a peeler or a small, sharp knife. Much of the nutritional content is stored in or just under the skin, so leave it on if possible. Otherwise, peel very thinly with a potato peeler, then rinse. New potatoes just need a scrub in cold water - the skin is too thin to warrant peeling.
If any area of an old or new potato is tinged with green it should be scraped or cut off, as it is mildly toxic.
Keep all potatoes in a cool, dark, well-ventilated place as, if exposed to light, they'll sprout green shoots. They should be kept in paper, rather than plastic bags, as the latter will make them go mouldy. Stored this way, old potatoes can last weeks, while new potatoes should last for a good few days.
Bake whole (50 minutes -1 1/4 hours); chop into big chunks and roast (45-60 minutes for old, 30-40 for new); chop into big chunks and boil (15-20 minutes for old, 12-15 minutes for new).
Try sweet potato.