Chestnuts
Chestnuts are large, deciduous trees in the beech family (Fagaceae) found in several temperate climates around the world. The trees produce starchy, edible nuts that can be processed into various foods. The nuts are enclosed in a spiky burr, which falls to the ground and opens up when the nuts are ready. The number of nuts in each burr depends on the species of chestnut.
There are four main species of chestnut: the European chestnut (Castanea sativa), the American chestnut (Castanea dentata), the Japanese chestnut (Castanea crenata), and the Chinese chestnut (Castanea mollissima). The American chestnut is nearly extinct; nearly all of the trees in its native range were wiped out in the 20th century by a fungal disease called chestnut blight.
In addition to these tree species, there are also shrubby species that are commonly known as “chinquapins”.
Species
Chestnuts
European chestnut (Castanea sativa)
American chestnut (Castanea dentata)
Chinese chestnut (Castanea mollissima)
Japanese chestnuts (Castanea crenata)
Chinquapins
Alleghany chinquapin (Castanea pumila)
Ozark chinquapin (Castanea ozarkensis)
Chinese chinquapins (Castanea seguinii and Castanea henryi)
Chestnuts
There are no native chestnut species in the Pacific Northwest. However, the region (and the West Coast in general) is extremely well suited to growing the European chestnut.
The European chestnut is found throughout France, Italy, Northern Spain and Portugal, the Balkans, and the lower Black Sea region. These regions share a high degree of similarity to the Pacific Northwest.
All chestnut tree species are considered drought-tolerant and prefer acidic, well-draining soils, which are found throughout our region. The Asian and American species generally prefer hotter, more humid summers than what we have to offer, and are better suited to the eastern side of the Rocky Mountains. Most of the European varieties have also been cross-bred with Chinese and Japanese species to provide additional disease resistance.
Efforts are underway to save the American chestnut tree, and the lack of chestnut blight in the Pacific Northwest means the area lends itself to those efforts, but in my opinion, for culinary purposes at least, the European chestnut makes for sense for the Pacific Northwest. Granted, I might be a little biased as these are the ones that I grew up collecting and eating.
Currently, there are a handful of chestnut orchards in the Pacific Northwest. I hope to see more of them pop up over time. Their popularity in the US does seem to be heavily tied to the immigration of Italian, French, and Swiss populations, but I think that a lack of knowledge or awareness of the nut is the main obstacle to its widespread adoption in our region.
Chestnut orchards can often be combined with livestock rearing, in particular pigs, which in traditional systems are often allowed to feed on leftover, undesirable nuts that weren’t picked during the harvest season.
Other chestnut species
The American chestnut, Castanea dentata, was once widespread in the eastern side of the United States, a major component of forests of the Appalachian mountain range. The American chestnut is the largest chestnut tree species, but has the smallest nut size other than chinquapins (shrub species).
Unfortunately, chestnut blight (Cryphonectria parasitica), a fungal disease, entirely wiped out the American chestnut in the 20th century. It is believed that the disease was accidentally introduced to the US around 1890 via Chinese and Japanese chestnut trees, selected for their smaller size to use in orchards. The disease was first noted in 1904, in the Bronx Zoo, and by the 1950s, the native population was essentially extinct in its original range. It is estimated that somewhere between 3 and 4 billion trees died.
Currently, isolated American chestnut trees can be found in the Pacific Northwest where they were planted by people. Chestnut blight has been found in our region but our climate is not conducive to its spread; our dry summers keep the fungus at bay. In fact, we have several champion trees in Oregon and Washington. Oregon’s champion tree, located in Gladstone, is about 100 ft tall. To be fair, though, historical trees were known to reach nearly double that size.
Breeding efforts have been undertaken to confer disease resistance to American chestnuts by crossing them with the blight-tolerant Chinese and Japanese species, which evolved alongside the chestnut blight fungus.
The Chinese chestnut (Castanea mollissima) and Japanese chestnut (Castanea crenata) can be grown across most of the United States. In the Pacific Northwest, their main limitation is their preference for hot and humid summers, though considering the number of varieties available in their native regions, it is highly likely that a good fit for the parts of our region with hotter summers could be found. Currently, one of the most important roles these two species plays is in its use for breeding blight-resistant varieties of chestnuts.
Chinquapins
Shrub-type chestnut species are commonly known as chinquapins or chinkapins. Chinquapins produce smaller nuts than chestnuts and though edible, they are generally not cultivated. However, they are sometimes collected in the wild for consumption.
There are two American chinquapin species: the Alleghany chinquapin (Castanea pumila) and the Ozark chinquapin (Castanea ozarkensis), thought to be the ancestor of the other American chestnut species. All are susceptible to chestnut blight and were heavily affected by the disease.
In Asia, there are two shrubs known as Chinese chinquapins: Castanea seguinii and Castanea henryi.
To make matters more confusing, several other tree species are commonly known as chinquapins, including species in the genus Castanopsis, Chrysolepis, and Quercus (oaks).
False chestnuts
Several other species share the common name “chestnut”, but are unrelated to plants in the genus Castanea.
Horse chestnut: the horse chestnut comes off of a large tree that is commonly planted as a city tree (and can be found throughout the Pacific Northwest). The tree produces inedible, toxic nuts covered in a smooth capsule with large spikes. They can be easily differentiated because true chestnuts are covered in a completely prickly capsule that is reminiscent of a hedgehog’s back.
Water chestnut: this name is used to refer to either Chinese water chestnuts (Eleocharis dulcis) or water caltrops (Trapa natans, Trapa bicornis, and Trapa rossica). None are true chestnuts, but all are aquatic plants that produce starchy edible seeds. Eleocharis dulcis is a tropical and subtropical plant, but water caltrops can easily be grown in the Pacific Northwest, and are considered a noxious weed in Washington state.
Cooking with chestnuts
Chestnuts are high in starch and fairly sweet as well. I like to think of them as something like a “potato nut”. To eat, they must first be separated from their shells, which are somewhat soft and can be pierced with a knife.
The simplest preparation for chestnuts is to roast them; in regions they are popular, chestnuts are often sold roasted by vendors. The shells must be scored before cooking or the nuts will explode when roasted. A small “x” is usually cut into them. A chestnut knife, which has a short, curved blade, can be used.
Chestnuts can also be dried and ground into chestnut flour. Chestnut flour features prominently in the cuisine of Corsica, where traditionally it was a staple cooking ingredient. Chestnut flour was used to make breads, cakes, and “pulenta” (a chestnut-based polenta).
The nuts can be mashed and mixed with sugar to create a paste or purée, which is commonly used in desserts and pastries. A classic dessert from France is the “Mont Blanc”, which features chestnut purée, whipped cream, and meringue. In Japan, chestnut purée is used similarly to bean paste as a filling for various sweets.
Candied chestnuts are a delicacy found in various northern Mediterranean countries but are especially famous in France and Turkey. In France, specifically larger varietals, referred to as “marrons” rather than “châtaignes”, are used for candying.
