Pine Nut

Pine nuts are the seeds of about 20 species of pine whose seeds are large enough to be worth harvesting. They develop inside woody cones and, in many species, are protected by a hard shell. Mediterranean stone pine produces long, slender, ivory seeds, while Korean pine and Siberian pine yield shorter, plumper kernels, and North American piñon pines produce small, round seeds. Because it can take about 18 months to three years for cones to mature, and the seeds must be extracted by hand or by machine, they are among the most costly nuts. The flavour is mild, resinous and sweet.

Edible pine nuts come from several regions. The Mediterranean stone pine (Pinus pinea) has been cultivated in Italy, Spain and Portugal. Korean pine (P. koraiensis) is harvested in north-east China, Russia and Korea, and supplies much of the world's pine nut trade. Chilgoza pine (P. gerardiana) grows in the western Himalayas, and piñon pines (P. edulis and others) grow in the south-western United States and Mexico. Most pine nut harvesting is still from wild or semi-wild stands, with cones collected by hand.

Pine nuts have been gathered by people since prehistoric times, and stone pine seeds have been found at Roman and earlier sites. They appear in Roman cookery and in medieval Mediterranean cooking. Native peoples of the American Southwest, including the Navajo and Paiute, relied on piñon nuts as a major source of food, gathering them in the autumn and storing them for winter.

Pine nuts have remained a prized ingredient in Middle Eastern, Italian and Spanish cuisine, and are used in sweet and savoury dishes alike. In the late twentieth century the popularity of pesto and Mediterranean cooking led to an increase in demand, and the trade broadened to include Chinese and Russian supplies. Prices have fluctuated with poor harvests, and some people have reported a temporary bitter, metallic taste after eating nuts from certain sources, a condition known as pine mouth.

Pine nuts are blended into pesto alongside basil, garlic, olive oil and cheese, and toasted for salads, grain dishes, stuffings and roasted vegetables. In the Middle East they garnish rice, kibbeh and meat dishes, and in Italian and Spanish sweets they are used in pastries and biscuits such as pinoli cookies. They can be ground into sauces and spreads. Toast them briefly in a dry pan over moderate heat and watch closely, since they burn quickly. Store in the refrigerator or freezer to avoid rancidity.

Pine nuts contain mostly unsaturated fats, including pinolenic acid in some species, and modest amounts of protein. They provide vitamin E, vitamin K, magnesium, manganese and zinc. Research on pinolenic acid suggests possible effects on appetite hormones, but the evidence in people is limited. As with other nuts, portions are small because of the calorie density. They are best used as a garnish or flavouring rather than a main source of protein.