Producing black walnut syrup shares similarities with the traditional process of making maple syrup, yet it presents unique challenges that necessitate research and the development of innovative methods. Like maple syrup, the extraction of black walnut sap involves tapping trees and collecting the sap during the early spring, when the sap flow is at its peak. However, black walnut trees have distinct characteristics and properties, leading to specific challenges in the syrup-making process. One of the primary obstacles lies in the chemical composition of black walnut sap, which differs from that of maple trees. The presence of pectin, a natural compound found in black walnuts, poses challenges in processing, filtering and achieving the desired consistency in the syrup. To overcome these challenges, Tonoloway Farm collaborates with Virginia Tech and Future Generations Universities, as well as the wider community of black walnut syrup producers, to test innovative production methods and conduct comprehensive studies on the distinctive harvest and production process of black walnut syrup. We are committed to advancing the understanding of black walnut sap extraction, refining syrup production techniques, and addressing the specific challenges associated with this unique forest food. Our research partnerships involves joint research initiatives, knowledge-sharing forums, and practical field trials aimed at optimizing the quality and efficiency of black walnut syrup production. By leveraging the expertise of academic institutions and engaging with fellow producers in the community, Tonoloway Farm aims not only to enhance its own syrup-making practices but also to contribute valuable insights to the broader community of black walnut syrup enthusiasts, fostering a culture of shared learning and innovation within the industry.
Research into Designing a Walnut Specific Spile, April 2020, by Mike Rechlin, Christoph Herby, “Chip” Matheny, and Karen Milnes:
This report details an initiative conducted through the 2019-2020 sap flow season to design and test a spile specific to walnut trees. Drawing off of findings from the 2019 “Walnut Sap Flow and Syrup Making Field Trial” the longer, more highly tapered spile design aimed to counteract problems identified in the previous study. This research was conducted with support from the Northeast Sustainable Agriculture Research and Education program. Download
The Effect of Vacuum on Walnut Sap Flow, April 2020, by Mike Rechlin, Kate Fotos, Christoph Herby, and Mat Cabral:
This report details an initial study on the effects of vacuum on walnut sap production. With low vacuum, averaging 8-inches Hg, sap flow doubled (p<0.05). Late in the season, the research team connected a larger pump, which pulled 20-inches Hg. Though not enough runs were conducted to determine a statistical difference, in initial observations, walnut trees produced over double the sap under higher vacuum. This research was conducted with support from the Northeast Sustainable Agriculture Research and Education program. Download
Walnut – Observations on The Timing of Tapping, 2020 Sap Flow Season by Mike Rechlin and Christoph Herby:
This report discusses an initial study on the proper time to tap walnut trees. Walnut trees are anatomically different from maple trees, indicating that they may have a different sap flow season. In the initial study, the data shows that walnut trees run concurren to maples. However, a single tap placed in late April produced an equal amount of sap in half a day as a tap did on average over the whole maple sap season. This research was conducted with support from the Northeast Sustainable Agriculture Research and Education program. Download
2022-2024 Virginia Tech / Southern SARE Research on walnut sap vacuum measurement and walnut syrup flavor profiling: (VT-SARE Research summary and reports coming soon)
Additional Resources:
Future Generations University web site on tree syrup research
Virginia Tech Department of Sustainable Biomaterials
Facebook Black Walnut Syrup Makers group
The Sugarmaker’s Companion, by Michael Farrell, the book that taught us to make syrup:
Contact us to plan a visit
Staunton VA: City Market
Starts April 6th
Richmond VA: RVA Big Market at Bryan Park
Saturdays 8am-12pm (year round)
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Saturdays 10am-1pm
