Researchers Tap Birch, Walnut as Syrup Alternatives
ITHACA, N.Y. — Maple syrup is an important part of the North Country economy, but producers are facing more and more challenges, including high production costs and poor sap seasons.
But researchers at Cornell, the University of Vermont and the University of Maine are studying an enterprise that could help keep syrup producers in the Northeast economically solvent: birch and walnut syrup.
Birch syrup has been produced successfully for some years in Alaska, British Columbia and other parts of Canada.
“Birch provide a significant financial opportunity for a valuable forest crop,” said Michael Farrell, director of Cornell’s Uihlein Sugar Maple Research and Extension Field Station in Lake Placid, N.Y.
Maple sap flow depends upon the freeze/thaw cycles to produce adequate stem pressure. However, birch sap flow depends on root pressure, which develops once the soil warms to about 50 degrees F. This means that birch sap is flowing just as the maple season is finishing, thus providing a potential complement to maple syrup production, Farrell said.
“When you hear the spring peeper, this marks the beginning of birch sap flow, which continues until the leaves open,” he said.
The equipment needed is identical for both the maple and birch sap and syrup processes; however, since birch sap is acidic, the use of metal containers and other stainless steel is discouraged in favor of plastic, Farrell said.
Birch sap is 1 to 2 percent sugar, so the evaporating process is slow and needs to be done carefully to prevent scorching. The sugars in the sap are fructose and glucose, which will burn at about 70 degrees C. The low sugar content also means that about 100 gallons of sap is need for 1 gallon of syrup.
“I wouldn’t even consider trying to make birch syrup without concentrating the sap first with a reverse osmosis system,” Farrell said.
The three most common birch species in North America are paper (white), yellow and black birch; any can be used for syrup production. However, David Moore, who has been producing birch syrup at The Crooked Chimney in New Hampshire since 2008, has shown paper birch has the highest sugar content, ranging from 1.6 percent down to 0.6 percent.
The low sugar concentration is a disadvantage from a production cost standpoint; however, birch sap products do have some health advantages over maple products, since fructose is the primary sugar compared to sucrose in maple. Fructose is more easily digested and assimilated by the human body, has a low glycemic index and is more suitable for diabetics.
Farrell said he was surprised more sugarmakers haven’t expanded their operations by producing birch syrup once the maple season has ended.
“At the Uihlein Forest in Lake Placid, we tap about 700 trees and are probably one of the largest birch syrup producers in the eastern U.S,” he said.
Birch syrup sells for about $20 for an 8-ounce bottle. The Alaska birch sugarmakers export their products to Italy and cannot keep up with demand, he said.
American Indians made syrup from black walnut, (Juglans nigra), something that is rarely heard of today. In Appalachia and the Midwest, the black walnut tree is reasonably common, but in the Northeast it is not as prevalent and is found primarily in fertile river bottoms.
As it is one of the most valuable timber species in North America, owners of black walnut may not even consider drilling trees; however, if the trees are not prime sawlog or veneer trees, drilling them for syrup could be worth considering, Farrell said.
There has been very little research performed on walnut syrup, its chemical make-up or aspects of the production process. All Juglans species produce the very toxic chemical called juglone, with black walnuts having the highest concentrations. However, since it is water soluble, it is not likely to be present in syrup, Farrell said.
Farrell did a workshop in Vermont on black walnut syrup production. After tasting the syrup — which Farrell described as surprisingly similar to a light or medium amber maple syrup, but with more butterscotch and nutty overtones — most of the participants were planning to go home and plant trees for tapping, he said.
It is not known if syrup from nut trees would be a problem for people with nut allergies, so it is very important to clearly label the product, he said.
There could be a niche market for walnut syrup, although it not as likely to be an additional source of income for the maple syrup producer since the sap needs to be collected at the same time as maple sap and it is unlikely that there would be many trees close to the sugarbush.
The yield of sap from black walnut trees is low, possibly due to the trees having a lot of heartwood and little sapwood, Farrell said.
“Maple syrup is not the only species that has a fake syrup substitute. Many of the black walnut syrups’ are actually just cane syrup with natural walnut flavor’ added,” he said. “To my knowledge there is only one commercial producer of walnut syrup.”
Other Juglans species are possibilities for syrup production. Syrup produced from Butternut (Juglans cineria) is described as having a nutty and almost fruity overtone. However, butternut trees are rare and are declining due to the butternut canker.
Information on the Uihlein studies will be published in “Sustainable Sugaring: Making the Most of Your Maple, Birch and Walnut Trees,” by Farrell, due to be released this summer by Chelsea Green Publishing.