When growing chestnuts at home, it is important for the grower to distinguish between the "real" chestnut trees and those trees producing horsechestnuts and buckeyes. The real chestnuts (CASTANEA spp.) belong to the Fagaceae family (beech), while the horsechestnuts and buckeyes belong to the Hippocastanaceae family. The seeds of the latter two are potentially poisonous, thus they should not be eaten. To distinguish between the edible chestnuts and the others, it is helpful to look at the fruit and leaves.
A comparison of characteristics includes:
Chestnuts | Horsechestnuts, buckeyes, etc ------------------------|-------------------------------- VERY prickly burr, which| A few, short, flexible prickles enclose the nuts | (easily handled). (1-3 nuts per bur) | (use leather gloves | to handle.) | | Fruit (bur) divides | Fruits divide into 3 parts. into four parts. | | Long, narrow, leaves | Leaves palmately compound with teeth at the end | buckeyes: 5 leaflets. of each major vein | horsechestnuts: 7-9 leaflets. | Starchy, edible | Bitter taste taste |
Today's varieties are similar to the native American chestnut, but are generally resistant to the blight that killed the American trees. They are easily grown in southern Michigan and are usually of Chinese or Korean origin. Those chestnuts available in stores during the fall are usually of European origin.
After harvesting the chestnuts, they should be seasoned for several days to remove excess moisture, and to retard mold formation while being stored or shipped. While seasoning, it is recommended to spread the nuts 1 or 2 layers deep on trays made of 1/2" mesh hardware cloth. If seasoned 1 to 2 weeks under warm, dry, windy conditions, the nuts may dry more than what is desired. A nut which has dried too much is indicated by a shell which can be pushed in a considerable amount. If chestnuts are to be cooked within several weeks after they are picked, they do not need to be air-dried. If they are to be eaten raw, they need a few weeks for the starch to slowly change to sugar (this occurs in both air drying and refrigerated storage). If the nuts are eaten right away, they may have an astringent taste. Green nuts of Korean origin are more palatable than green nuts of Chinese origin.
Chestnuts can be kept in a refrigerator for several months. The nature of the air should be noted: chestnuts dry quickly in dry air and mold quickly in damp air. When using refrigerator storage, the nuts should be placed in in a closed paper sack and left for 1 to 2 days, until they have reached refrigerator temperature. They should then be transferred to a sealed plastic sack and about a dozen holes punched in the plastic with a medium nail.
Some helpful suggestions for harvesting include: placing the harvested nuts in milk cartons, each layer separated by dry peat moss, as it comes from the package. After the package is tightly closed, the nuts should last for several months. The use of freshly dug sand has also been suggested. The sand should be dried in the sun with occasional mixing until it is only VERY SLIGHTLY damp. The sand should be cooled before it is used in the milk carton. Sand keeps chestnuts in good viable condition for 2 years by storing the freshly picked chestnuts in sealed plastic bags and maintaining a temperature of 26-30 degrees F.
If molding occurs in the refrigerator, wash and/or scrub the nuts to remove the mold, and then place on paper toweling. After one or two paper changes, allow them to room dry for several hours. After drying, replace the nuts in a paper sack in the refrigerator until they are chilled and then transfer them to a clean plastic bag with holes punched in it. If mold persists, the kernel may become "off-color" and no longer edible. If mold has been present, any bad kernels can be spotted by cutting the nuts in half before cooking.
The most popular method of cooking chestnuts is roasting. DO NOT roast a chestnut until one or two holes have been punctured in each shell. If not punctured, the build-up of steam pressure within the shell can lead to the explosion of the nut, with considerable noise and force. When roasting chestnuts over "an open fire", it is safe to use a covered utensil with a long handle. If using a conventional oven, heat the nuts at 300 F for about 15 minutes. It may be necessary to experiment with this. Leaving one nut unpunctured will determine when the nuts have been roasted enough--when it explodes, the other nuts should be done.
Boiling is another method employed in the preparation of chestnuts. Before boiling, cut the chestnuts in half with a sharp knife. Using a rather shallow pan with a cover, add only enough water so the nuts are not completely covered. Bring the nuts to a boil and then reduce the heat and boil for 15 to 20 minutes. After, drain, allowing them to cool a bit. When cooled, the kernels should come out readily. The longer the nuts are cooked, the mealier the kernels become and the more they crumble upon removal from the shell.
Another method of boiling includes boiling the chestnuts somewhat vigorously in a deeper kettle with more water. After a few minutes, the kernels will begin to fall out of the half shells. After draining, remove the rest of the kernels from the shells and then cook as much as desired in another kettle of fresh water.
Steaming the chestnuts is the best method for easy removal of the kernel, and works well for nuts which have dried too much. To begin, cut the chestnuts in half. An initial steaming time of 8 to 10 minutes is recommended. Following steaming, drain and cool the nuts a bit and remove any kernels which haven't already fallen out.
Using the microwave oven easily separates the kernel from the shell. The flavor of the nuts resulting from this method depend on the number of nuts being cooked, the degree of dryness of the nuts, the temperature setting, and the length of time cooked. This method also begins with cutting the nuts in half. The nuts are then placed cut end down on a double layer of paper towels. For a start, try using eight medium-sized nuts and a roast setting for two minutes. The nuts may be covered with butter, garlic, salt; or used in other recipes.
Cooked chestnuts may be kept in the refrigerator in jars for a considerable period of time, or in the freezer for an even longer time.
Although Buckeye and Horse Chestnuts are not considered "true" chestnuts and are not suggested for eating, these varieties are included in both "Edible Wild Plants of Eastern North America" and "Poisonous Plants of the United States and Canada." In actuality, their nuts are quite bitter, which prevents most people from eating them. At one time, the Indians roasted, peeled and mashed the nuts, and then leached them for several days before using them. It was reported in 1860 that "The powdered seeds and bruised branches, if thrown into small ponds and stirred awhile, will so intoxicate fish that they rise to the surface and may be taken by hand." In general, is is wise to consider all species of buckeyes and horse chestnuts as potentially toxic to stock and humans.
Early fall is the time of year to collect edible native nuts and fruits such as black walnuts, butternuts, hickory nuts, papaws, buckeyes and horse chestnuts. Collecting should begin with the location of bearing trees that have high quality fruit. These nuts should have good kernels inside, which can be used for a number of decorative purposes.
Lee Taylor, Hortopics: 10/84 Hortopics: 9/81 Michigan State University
Contributor: Norman C. Higgins, Michigan Nut Growers Association