Spinach is a green vegetable used as an accompaniment to main dishes, and as an ingredient in many other dishes (the term florentine in a recipe indicates the presence of spinach). Young leaves can be eaten raw in salad, tacos, and burgers. Frozen spinach goes well on pizza.
Plain cooked spinach is best served steamed or boiled in a minimum amount of water for no more than five minutes. The bulk of the leaves reduces enormously in cooking. Allow about 100 g per serving and use the biggest pan you have. Serve with lemon juice, or perhaps with salt.
Spinach can be bought loosely or in prepackaged bags. You can get better quality when you buy loosely, because you can examine all the leaves. When examining the leaves, pick the ones that are smaller and have a good green color to them. Leaves that are crisp and spongy are of good quality. Do not pick leaves that are wilting, brown or yellow. Fresh spinach should smell sweet, never sour or musty. Look for stems that are fairly thin and coarse. Thick stems indicate overgrown spinach, which may be leathery and bitter. If only bagged spinach is available where you shop, check whether the contents seem resilient when you squeeze the bag.
Spinach loses much of its nutritional value with storage of more than a few days. While refrigeration slows this effect to about eight days, spinach will lose most of its folate and carotenoid content. This is worth considering when purchasing spinach out of season. If the product has been "in transit" (picked, cleaned, shipped and shelved) for more than one or two days it will need to be used almost immediately to have much nutritional benefit. This is in spite of the taste and appearance of the plant which may still seem fine.
Fresh spinach should be cleaned thoroughly and then can be stored loosely in an unsealed bag in the crisper tray of the refrigerator for a few days. Even at 4°C, spinach loses much of its nutritional value by eight days so for longer storage it should be fresh frozen, cooked and frozen or canned. Storage in the freezer can be for up to eight months.
It is sometimes discouraged to reheat spinach leftovers since poisonous compounds are formed during this process. What is behind this advice is that certain bacteria can grow on prepared nitrate-rich food, such as spinach and many other green vegetables. These bacteria can convert the nitrates into nitrites, which may be especially harmful to infants younger than six months. The nitrate-converting enzymes produced by the bacteria can convert even more at elevated temperatures during the second heating. For older children and adults, small concentrations of nitrites are harmless, although formation of nitrosamine compounds from the nitrites could be of concern for adults as well. 
- The oxalic acid contained in spinach can react with the calcium contained in milk to produce a deposit on your teeth. You may wish to avoid serving milk with spinach.
- The oxalic acid contained in spinach is bad for cast iron pans and carbon steel pans. Spinach will turn black when cooked in such pans.
|Seasonality tables|Autumn|Winter|Spring|Summer|All year|
Spinach is a 'cool season' crop, which means it's best planted in cold ground, at the end of the winter, making it available from early spring. Many spinach cultivars can also be planted in the late summer months for a fall crop. In cooler climates, the season may last throughout the summer. In the beginning and end of the year spinach grown in greenhouses (which has smaller leaves) is available. Frozen spinach is also a popular alternative out of season.