Are all types of pine nuts edible?

According to the United Nations Food and Agriculture Organization, only 29 species provide edible nuts, while 20 are marketed locally or internationally because the size of their seeds is large enough to make them worth harvesting; in other pine trees, the seeds are also edible, but they are too small to have any significant value as human food. You may be familiar with pine nuts, the delicious little teardrop-shaped nut often used to make pesto and to cook other dishes.

Pine nuts

(also called pignoli) are the edible seeds of pine trees. Seeds are the inner part, usually edible, of a hard, inedible shell.

Many species of pine trees produce edible pine nuts. These nuts are actually the grains that are released when pine seeds break, and each cone usually has numerous seeds. Different pine species have seeds of different sizes, different ease of cracking and different flavors; the worst flavor is that of turpentine. Pine nuts are highly nutritious and have been an integral part of the native diet in many parts of the Northern Hemisphere for thousands of years.

There are at least 18 species that produce edible nuts. However, only four species have been cultivated for their seed crops: Pinus pinea and P. Other species are regularly collected in native forests. Some of these sources, especially in China, are declining as forests are cleared for wood.

The pine nuts normally found in stores almost always come from stone pine (Pinus pinea) from Italy or Korean pine (Pinus koraiensis) from China. Several species of pine trees that produce edible nuts grow well in New Zealand, and the drier parts of the South Island are renowned for their good seed production. The pineapple is the most common species here and is occasionally described as a possible commercial species. However, much more research needs to be done before we can make informed predictions about a potential pine nut industry.

The easiest way to get the pine nuts out of the cone is to place the pine nuts and let them dry on their own. This will cause the remaining pine nuts (those that haven't eaten the bugs yet) to fall off the pineapples and fall onto the canvas. This condition, called “pine nut mouth” or “pine nut syndrome,” means that simply eating pine nuts makes the other foods you eat taste bitter and metallic. Species with larger nuts are worth exploring and saving yourself some trouble with peeling.

I wouldn't recommend breaking the pine nut shell because you'll probably also break the small nut inside. Most of the world's pine nut-producing species can be cultivated in New Zealand, and there is evidence that some species can produce good nut production. Since the pine nuts are ready to harvest about 10 days before the cone starts to open, they are very difficult to remove. This soil is likely to contain fungi that live in close physical association with pine, for their mutual benefit.

From a commercial point of view, the cost of production, time of cultivation and perceived prices are currently barely sufficient to create a viable industry, and the immediate market prospects for edible pine nuts grown in New Zealand are not promising. Korean pine is interesting because its cones fall intact, making it less expensive to harvest than other pine trees. If the growth is exuberant, such as in fertile soils, remove approximately one out of every two branches so that the flow of sap is not prevented, thus preventing the formation of nuts.