Introducing the Heartnut!
People who taste the heartnut for the first time are immediately impressed with the mild sweet walnut flavor. Most notice that there is no bitter aftertaste often found in the Persian or English walnuts that dominate the walnut industry. This lack of bitterness alone provides greater culinary opportunities to the discriminating cook and thus a reason for this unique cookbook, the first cookbook for the heartnut ever published.
Originally from Japan, the heartnut Juglans ailanthifolia var. cordiformis is considered to be a natural "sport" or genetic oddity of the more common Japanese walnut, Juglans ailanthifolia. Almost all of the characteristics of the two tree are identical except for the shape of the nut. Instead of the normal egg shaped nut, the heartnut is a flattened locket or heart shape, thus the name heartnut. This heartnut form appears to be quite unstable genetically. A heartnut seed planted to grow a tree will just as likely produce a normal Japanese walnut as it will a heart shaped nut. Even the heart shape and nut size are quite variable from tree to tree grown from the same parent stock. Some are almost perfect "Valentine" heart shaped while others can be narrow, lacking any resemblance to the heart shape. Heartnuts can vary in nut size from "penny" size to greater than silver dollar size. Variability is so great that one would think that, "God isn't finished with this tree yet!"
This trait of variability offers the breeder wonderful opportunities to develop improved cultivars. The Japanese walnut has little value as a commercial nut tree, simply because the nuts are difficult to crack and extract the kernels. They have internal shell membranes that bind the kernel pieces. The most desirable heartnuts on the other hand open like a locket on the seam when they are cracked, releasing the kernel whole or more often in two pieces when they split at the top of the kernel. Most heartnuts grown from seed will not open and drop the kernel freely, but need to be pried out. Occasionally, a heartnut will have an internal cavity that is so round and open that there is no part of the shell that can pinch and bind the kernel. It is these trees that are valued as commercial cultivars. Once grafted trees of these cultivars are established, orchards of heartnut trees can be planted to produce these easy cracking nuts. Commercial cracking facilities then can process these "designer" nuts and sell the kernels.
The shells can also be marketed. Half shells have applications for craft use, while ground shells, unlike sand, are non abrasive so they can be used in the metal industry in an air blast application to clean, polish or finish delicate metal surfaces. Ground shell can also be added to the rubber in automobile tires, providing better traction.
The heartnut is best adapted to a northern, temperate, maritime climate like its native land, Japan. The mildest fruit growing regions of eastern North America, particularly near the Great Lakes in Ontario, New York and Michigan are the ideal areas of North America to grow this fine nut. They produce best where summers are warm, winters are moderate, spring frosts are minimal and moisture is abundant.
The heartnut is resistant to bacterial blight which limits the commercial production of the Carpathian or Persian walnut in the east. Spring and summer rains are welcomed by the walnut trees, but the blight also thrives in such a condition, limiting the potential of this commercial nut in the east. In California, where the Persian walnut is grown, spring and summer rains are almost non-existent, saving these trees from infection. In the California hot dry climate, on the other hand, the heartnut is less happy.
Though cultivars with interesting names like Imshu and Locket exist, there is still room for more selections through breeding. The heartnut is a close relative of the North American native butternut, Juglans cinerea with which it crosses freely. The butternut is our most hardy walnut, growing widely across eastern North America from Manitoba to New Brunswick. Crossed with the butternut, the heartnut gains the butternut hardiness, the heartnut resistance to disease, along with hybrid vigour, a very inviting combination. Though few crosses have been selected with the heartnut shape, the potential for the serious breeder is exciting.
Ernie Grimo - Taken from Nuts About Heartnut Cooking, - A Heartnut Lovers Delight
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SONG Members would like to thank the CanAdapt Small Projects Initiative 2000. Without their assistance this project would not have been possible.
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