How to tap black walnut trees for syrup
I had no idea you could tap black walnut trees, did you? These trees can be tapped in late winter to produce a syrup similar to maple syrup? If you have access to black walnut trees, this is a great way to put them to use.
Black walnut trees are unique in that the sap runs in winter, spring and autumn. The trees produce sap that runs easily and prolifically any time the day and night time temperatures are in the proper range -- a few days of freezing temperatures, followed by temperatures that are below freezing at night and well above freezing during the day. That said, for syrup making purposes, the best time to tap black walnut trees for syrup making is in late winter, generally between January and March. There is significantly more sap produced during this time of year than any other.
In 2003 and 2004, the forestry division of the University of Kansas undertook an experiment where they tapped twenty black walnut trees and measured the amount of sap they produced in comparison to maximum and minimum daily temperatures, wind speed and more. The excellent studyincludes detailed information on how to tap trees and the results of all of their analyses, including the results for various tree diameters, the sugar content variances between trees and more.
A more in-depth study was performed at in four sites in New York, Pennsylvania, and Indiana during the winter of 2014. This study found that the yield of sap for black walnut syrup was lower than that of maple trees, making it less likely to be successful for a business enterprise. They concluded that it could still be profitable because black walnut syrup is "a unique, novelty item that can potentially sell at much higher prices than maple syrup," especially when sold in small, decorative bottles for the gift market.
A member of Maple Trader described tasting the syrup from one of those test sites:
I have had walnut syrup at the maple school at Paul Smiths college, that was sponsored by Cornell university. It was very good, a lot like maple. If I remember correctly, the walnuts don't produce as much sap as sugar maples, but the syrup was awesome.
I had read that one can tap black walnuts. Finally did it yesterday. They flow just as well as maples, and have quite a bit of sugar in the sap to boot. When finished, the color was a very light yellow color, similar to vegetable oil. The taste... sweet, with the essence of walnut.
The way that black walnut trees are tapped for syrup making is basically the same as the way sugar maple trees are tapped. You can find detailed instructions for tapping trees at Ohio State University's Fact Sheet. For directions specific to black walnut trees and lots of photos, Homestead Honey also has a detailed tutorial. If you plan to harvest your walnut trees for lumber, she recommends tapping lower to the ground. Others choose to tap walnut trees that are imperfect or not bound for the lumber market.
Some people recommend plugging up the hole after tapping is complete, but the UnderStory, a site maintained by ecologist Katie Burke, says:
A bit of upfront myth-dispelling is in order: Trees heal pretty quickly from holes poked in them for tapping. To a big tree, this is a super small hole. It’s not that different from you having blood drawn for a blood test. At some point in the past, people starting plugging up holes from tapping or tree increment coring (for tree ring research), using a variety of materials and chemicals to plug up the hole. But comparisons of plugged and not-plugged trees show that it doesn’t really do anything to help the tree (See here and hereand here), although it probably does make the person feel better. It’s generally best to let the tree heal on its own.
The taste of black walnut syrup is described as similar to maple syrup, but nuttier. Michael Jaeb, owner of Simple Gourmet Syrups in Ohio, described the syrup to Farm Show:
It looks like a Grade B, dark maple syrup on steroids. It has a robust, earthy flavor that’s a little smoky. People buy it because of the flavor and because it’s so rare.
The researchers of the Kansas study undertook a taste test between walnut syrup, walnut syrup mixed with sugar syrup, maple syrup and a commercial maple-flavored table syrup made with high fructose corn syrup and artificial flavors (Log Cabin). They found that testers did not prefer either tree syrup over the other and 85% of the taste testers preferred the artificial syrup. They wrote:
Descriptive sensory analysis showed that the table syrup's profile was clearly different from that of either walnut or maple syrup, whose profiles were relatively similar to each other. The pure walnut syrup samples from both years were characterized by nutty, musty/earthy, and woody attributes.
If you like the taste of maple syrup, you're likely to also enjoy the taste of walnut syrup. It's also worth noting that maple syrup contains dozens of beneficial vitamins and minerals. While no nutritional studies have been done on black walnut syrup, the sap was once used to treat inflammationand the vitamins, minerals and antioxidants are likely to be similar to those in maple syrup.
In addition to black walnuts and sugar maples, there are many other trees that can be tapped for syrup making. Other maple varieties can also be tapped, though the sap is typically less sweet. Birch trees can be tapped for syrup that is quite smoky tasting and delicious, though it's not as well suited for sweet uses like pancake syrup. Box elder trees can also be tapped, as can many others. Trees with higher sugar content in the sap will make the best syrups.