Final report for LNE20-410R
Project Information
Problem, Novel Approach, and Justification
The Northeast SARE funded project Centrifuges to Clarify Maple and Walnut syrup addressed the problem of syrup clarity in the production of maple and walnut syrup as well as walnut sap chemical composition. It attempted to develop a cost-effective alternative to the industry standard of filtering using diatomaceous earth as a filter aid. The proposed project promised environmental and health benefits. To achieve that result, the Future Generations University team worked with engineers at the Robert C. Byrd Institute of Advanced Manufacturing as well as engineer and syrup maker Greg Christian in re-engineering an “Extreme Raw Power” centrifuge from WVO designs. To better understand the suspended particulate matter found syrup we worked with the Chemistry Department of Marshall University to centrifuge syrup samples and quantify plug particle size. As research progressed, work on the project pivoted to place a greater emphasis on the second issue of centrifugation to remove pectin from walnut sap.
Future Generations University hypothesized that with the proper knowledge inputs and engineering expertise a basket centrifuge can be designed and constructed to efficiently and safely clarify maple and walnut syrup. Further, the team hypothesized that this device will be a cost-effective improvement on presently used syrup clarification techniques.
It was found that suspended particles in syrup could be greatly reduced, but not entirely eliminated, through centrifugation. Following up on the foaming issue encountered by Charles Chase in his 2017 centrifuge study (Northeast SARE FNE15-823) the team found that the application of vacuum to the centrifuge camber eliminated the problem. Finally, after the pivot to walnut, it was found that centrifugation of the sap allows it to be successfully run through a reverse osmosis unit to concentrate sugars prior to evaporation. The exact nature of the waste from this process and its relationship to what is assumed to be pectin in walnut sap is still being investigated.
Research findings were shared with farmers in the maple syrup production business through presentations at trade shows, and national-reaching trade publications like The Maple News and the Maple Syrup Digest. If successful, Project advisors will also facilitate discussions with maple equipment manufacturing companies to launch broader manufacturing and distribution of the new clarification technology.
To design, test, refine, and scale a cost-effective centrifugal separator for maple and walnut syrup clarification.
The Northeast SARE funded project Centrifuges to Clarify Maple and Walnut syrup addressed the problem of syrup clarity in the production of maple and walnut syrup as well as walnut sap chemical composition. It attempted to develop a cost-effective alternative to the industry standard of filtering using diatomaceous earth as a filter aid. The proposed project promised environmental and health benefits. To achieve that result, the Future Generations University team worked with engineers at the Robert C. Byrd Institute of Advanced Manufacturing as well as engineer and syrup maker Greg Christian in re-engineering an “Extreme Raw Power” centrifuge from WVO designs. To better understand the suspended particulate matter found syrup we worked with the Chemistry Department of Marshall University to centrifuge syrup samples and quantify plug particle size. As research progressed, work on the project pivoted to place a greater emphasis on the second issue of centrifugation to remove pectin from walnut sap.
It was found that suspended particles in syrup could be greatly reduced, but not entirely eliminated, through centrifugation. Following up on the foaming issue encountered by Charles Chase in his 2017 centrifuge study (Northeast SARE FNE-823) the team found that the application of vacuum to the centrifuge camber eliminated the problem. Finally, after the pivot to walnut, it was found that centrifugation of the sap allows it to be successfully run through a reverse osmosis unit to concentrate sugars prior to evaporation. The exact nature of the waste from this process and its relationship to what is assumed to be pectin in walnut sap is still being investigated.
Research
Future Generations University hypothesized that with the proper knowledge inputs and engineering expertise a basket centrifuge can be designed and constructed to efficiently and safely clarify maple and walnut syrup. Further, the team hypothesized that this device will be a cost-effective improvement on presently used syrup clarification techniques.
- literature review of maple and walnut syrup composition
- lab analysis of maple and walnuts syrups and sap composition
- photometric analysis of syrups filtered through centrifugation: Hanna Instruments maple syrup grading photometer
- review of "off the shelf" option for centrifuge as filtration system: "Extreme Raw Power" Centrifuge
Lab Research performed at Marshall University:
Treatments:
- 100 2 ml-samples of unfiltered maple syrup and walnut syrup were centrifuged in a laboratory bench batch centrifuge at set speeds between 3,000-15,000rpms, to separate the suspended solids, niter, from clarified syrup.
- Likewise, 2 ml-samples of unprocessed walnut sap was centrifuged at set speeds (size and speed to be determined by experimentation) to separate the dissolved pectin (molecular weight 60,000 – 130,000 gr/mole) from the approximately 2% predominately sucrose (molecular weight 342 gr/mole).
- For each sample set, turbidity was monitored to determine pre- and post-centrifuged sample clarity, pectin will be identified and examined, and elemental analysis was performed to quantify metals that may be present in maple and walnut niters.
Methods:
To determine the degree of clarity of the centrifuged syrup, and the characteristics of the settled solids (necessary to design a continuous flow commercial size syrup clarification centrifuge):
- Clarified liquid was decanted and light transmittance, a characteristic of syrup clarity, will be determined using UV/vis spectroscopy. This indirectly measures light scattering, which can indicate how much material centrifugation has removed.
- Wet weight of the settled solids (syrup niter) was determined for each sample run at each speed by weighing the samples prior to centrifugation and after decanting the clarified liquid. Each pellet of settled solids was then be dried and weighed to determine dry weight.
- Mass spectrometry (ESI and MALDI-TOF) was used identify galacturonic acid, the main component of pectin, present in any pelleted material strata. A pectin layer, if visibly identified, was extracted for positive identification.
- An inductively coupled plasma optical emission spectrometer was used to detect heavy metals.
- A randomly drawn sub-sample of various set speeds was examined and photographed under microscope to determine particle size remaining in the syrup.
Walnut sap samples were also analyzed to determine effectiveness of centrifugation in removing pectin from the sap by determining the concentration of pectin in the sap prior to and after centrifugation at the various speeds.
Data collection:
- Percent light transmittance of the clarified syrup recorded through UV/vis spectroscopy and compared across set speeds. An increase in light transmittance indicates higher clarity.
- Wet and dry weights of the pellet collected to determine amount of materials separated following centrifugation at various speeds.
- Charge-to-mass ratios from mass spectrometry that can be compared to databases to determine unknown molecules.
- A standard curve will be used to quantify heavy metals of interest in ppm.
- Visual analysis of the pellet and microscopic analysis of the clarified syrup.
Replications will allow a statistical analysis of the results to show the degree of clarity achieved at each set speed and the physical nature of removed solids.
Centrifuge design at RCBI:
Separation by centrifugation is dependent on: 1) characteristics of the input mixture (viscosity and particle size to be removed); and 2) the independent design parameters of the centrifuge (rotational speed, bowl diameter, basket slope, and centrifuging duration). Each of these design parameters must be optimized for the machine’s specific use. Using an iterative approach, we studied the effect of each of these parameters for maple and walnut syrup and considered variations on the design for optimization.
Once the initial chemical analysis was in-hand, the team experimented with existing centrifuges and considered custom design opportunities. This process consisted of the following steps:
- Testing an Extreme Raw Power centrifuge to duplicate Charles Chase’s 2017 study. This provided a baseline by which to compare proposed design modifications.
- Modifying the Extreme Raw Power unit to achieve desired outputs based on the results in the above testing, chemical analysis conducted by Marshall University, and advice from collaborating engineers at RCBI.
- Initially, the methodology intended for a design and fabrication of a prototype syrup centrifuge to take place. The optimal design will be a centrifuge that:
- Produces clarified syrup that meets the light transmittance thresholds for various syrup grades as set by the International Maple Syrup Institute.
- Produces syrup at a rate equal to or greater than that obtained through filtration clarification methods.
- Achieves manufacturing and operating costs comparable to a commercial maple syrup filter press, including costs of the consumable filter paper and DE required for its operation.
Methods:
- After testing an Extreme Raw Power with a Cleaning Booster centrifuge, the design team will reverse engineer that machine, analyzing its design, materials, and architecture.
- Depict proposed modifications for initial prototype and subsequent iterations using CADD drawings, 3D inventor files, and 2D CADD available through RCBI’s computer facilities.
- Machining the first prototype and subsequent iterations will take place at RCBI facilities. This state-of-the-art automated machine shop will allow for fine-tuning of the centrifuge design with each subsequent iteration.
Data Collection:
The following data will be collected when testing the various iterations of the syrup centrifuge: All testing will be done on well-mixed samples of maple and walnut syrup.
- Measure weight of the syrup before and after centrifugal clarification and weight of the niter removed
- Residence in centrifuge (duration of centrifugation) and speed set
- Light transmittance, as measured by a spectrometer, before and after each
- Each syrup sample will be graded using IMSI maple syrup grading standards before and after each test.
- Total machining costs
Centrifugation studies
- 3,000 rpm was a threshold speed for separating solids (called niter or sugar sand) from syrup.
- 8,000 rpm was a threshold speed for pellet (presumed pectin) formaton in walnut sap.
- Late season sap spun at 8,000 rpm results in a gel (presumed pectin) as part of the pellet.
Centrifuge studies
- The Extreme Raw Power centrifuge, spinning at 6,000 rpm, removes a significant portion of the niter or sugar sand. Issues remain with foaming.
- Pectin can be spun out of walnut sap; higher efficiencies are expected with the proper filter aid.
Future Generations University received notice that the project was funded and less than one month later, project partners, Marshall University and RCBI were shutting down in reaction to the COVID-19 situation. This caused unforeseen delays in the research timeline and meant that most of the research work was not able to begin until their facilities reopened in June. At this point, a progress report brought everyone up-to date and a 6-month work plan was developed. The meeting was also important in that walnut sap and syrup needed for the lab work was delivered to Derrick Kolling at Marshall University.
Kolling was able to move forward by hiring undergraduate chemistry student Hayden O’Dell to begin the lab analysis on walnut sap and maple syrup. Additionally, an “Extreme Raw Power” centrifuge was purchased for Greg Christian to begin experimenting with the workings of an “off the shelf” machine. Also purchased was a Hanna Instruments Maple syrup grading Photometer for Marshall University to test the clarity of their centrifuge experiments.
In the summer of 2020, Marshall labs were more-or-less closed, therefore O’Dell worked on a literature review focusing on the chemical composition of maple say and syrup and in the lab on the maple and walnut syrup particle analysis whenever possible.
On September 24, 2020 a second research team meeting was held at RCBI. By this time, particle analysis work was nearly complete, and the analysis prepared by Hayden was reviewed. This analysis gave Christian the information he needed to use with the results of his experimentation with the Extreme Raw Power centrifuge and plan the modifications to move forward with the centrifuge redesign.
With the Marshall University labs reopening over the summer, 2021 was a much more productive year for this research. The focus of the research continued to be two pronged.
The pectin problem: Work with Marshall University focused on practical and field applicable ways to identify and reduce the amount of pectin in walnut sap. With pectin in the sap, walnut syrup producers are not able to concentrate the sugars using reverse osmosis (RO), a technique commonly used in the maple industry. Pectin also makes filtering of the syrup very difficult. Focusing on pectin was a pivot in the analytical work from a more general understanding of the chemical composition of walnut and maple sap and syrup to solving a problem holding back the advancement of the walnut tapping industry
Clarification of syrup: At Tom’s Creek Maple, work continued using the “Extreme Raw Power” centrifuge to overcome problems with using centrifugation to remove niter (sugar sand) from maple syrup.
2021 Research Results:
Pectin:
- Over the summer of 2021, Hayden O’Dell discovered that it was possible to use a lab centrifuge to separate and quantify small quantities of what is presumed to be pectin from walnut sap. Up to this time, these centrifugation studies at Marshall had focused on a size particle analysis of niter from maple syrup. It was known from previous studies at West Virginia State University that a distinct gray layer of presumed pectin separated in the centrifuge plug of walnut syrup. Through dry weight analysis, O’Dell was then able to quantify the pectin in the plug at various speeds and spin durations (figure 1). This is the first time that the small quantities of pectin found in sap could also spin out, opening the possibility of reducing the quantity of pectin in walnut sap through centrifugation (Appendix 1 Walnut Sap Dry Mass 9-9-2021)
Figure 1. Dry weight analysis of centrifuge plug for early and late season walnut sap.
- Hayden’s work was on a bench centrifuge using 2ml samples. To be practical for a syrup maker the centrifuge would have to be a continuous flow machine. The most readily available and reasonably priced continuous flow centrifuge is a cream separator. Cream is light and floats on the heavier milk. Observations from the previous year indicated that pectin floats or rises to the top of the boiling syrup. A question raised is does pectin, with a high molecular weight, when moving into a matrix with sugars in the sap (gelling) form a layer that is lighter than the sap? To probe these questions and test an inexpensive continuous flow machine we did several experiments using commercial pectin with a cream separator (Appendix 2 Cream Separator). These experiments showed that, based on color, a separation did occur and that it could occur in a continuous flow machine.
- The next step was to see if that translucent gray layer in the centrifuge plug is in fact pectin and then to do it in a way that is field applicable in a sugarbush. The team was looking for a technique that could be used to determine if the sap pectin level was low enough for it to be concentrated with an RO. Because what is refer to as “pectin” is comprised of a variety of similar but chemically different molecules; its analysis is complex and requires the sophisticated instrumentation of an organic chemistry lab. Something is needed that could be done in an environment more similar to the back of a barn.
Because pectin is a polysaccharide, made up of long chains of monosaccharides which are simple sugars, a refractometer was tried. Refractometers are found in every sugarhouse and are used to measure the brix (% sucrose, a simple sugar) in the sap. The hypothesis was that changes in sucrose concentrations could be used as a proxy for pectin. Hayden conducted several experiments over the summer and found that, although an interesting idea, it did not work (Appendix 4 Walnut Sap and the Pectin Problem).
With the discovery that it seemed as though pectin plug could be spun out from walnut sap using centrifugation, attention turned from “the barn” back to the chemistry lab to see if it was possible to positively identify and quantify pectin in the centrifuge tube plug. A literature review of analytical tools to identify and quantify pectin led to an acid/base titration method (Ranganna, 1995) as the preferred method due to its simplicity and applicability without the need sophisticated analytical instrumentation. O’Dell proved the technique using commercially available pectin but found that it could not be used with the small sample quantities available from centrifuging 2ml sap samples.
- In the meantime, project PI Mike Rechlin wrote a literature review and summation of the issues related to pectin in a document “The Pectin Problem” (Appendix 4 Walnut Sap and the Pectin Problem). This was done to get a more wholistic view of the problem we were addressing, from tree to syrup, synthesize our research to date, and to provide direction moving forward towards solving the problem.
- With the possibility of using centrifugation to reduce or eliminate pectin from walnut sap and Marshall University’s chemistry labs now open, the team moved forward in the fall of 2021 with an experiment that combined the field work at Tom’s creek Maple with the analytical work at Marshall University. In November, project PI Mike Rechlin and Greg Christian at Tom’s creek spun the limited quantity of walnut sap still on hand (frozen from last sap flow season) through the “Extreme Raw Power” continuous flow centrifuge spinning the sap at 6,000 rpm (approximately 4,000xg) at a slow feed rate. The raw walnut sap and the sap that had been centrifuged were then taken into Marshall’s lab where Hayden O’Dell used his desktop analytical centrifuge and spun both samples at 8,000rpm for 5 minutes. A visual analysis of the resulting centrifuge plugs showed a marked reduction in the size of the plug that had been spun in the extreme raw power machine, indicating that pectin levels could be reduced by centrifugation in the raw walnut sap (Appendix 5 Centrifuge Studies at Toms Creek).
Syrup Clarification
Having the size particle analysis from Marshal University at hand, work at Tom’s Creek Maple focused on the removal of niter or sugar sand from the syrup. This work was conducted on the Extreme Raw Power commercially available continuous flow centrifuge, with 6,000RPM and achieving approximately 4,000xg, and a cost of approximately $1,600. The use of an off-the-shelf centrifuge instead of designing one from scratch was to have a tool that was affordable for the average syrup maker. The design strategy focused on modifying this existing product to make it better for clarifying syrup.
- A 2017 syrup centrifuge study by Charles Chase (FNE 15-823) had problems with foaming of the centrifuged syrup. This research worked to eliminate this problem by the application of vacuum to the centrifuge chamber. The theory being that without air present foam would not form. The experiments were largely successful, removing most of the foam from the samples. This technique has the potential to eliminate all the foaming problem with a larger vacuum pump.
- Niter removal studies continued with attempts to clarify maple and walnut syrup. This included designing and 3-D printing a basket to hold filter paper and diatomaceous earth, or other filter aid, to chelate the finer niter particles. These studies are continuing.
Figure 2 - 3-D printed basket that could be used with filter paper and a filter aid to clarify syrup.
2022 Research results
Following the third year Novel Approaches grant workplan (attached) the project team took what was learned about sap and syrup clarification in a lab setting into the field. Because there had been little success clarifying maple syrup in the lab experiments, work focused on scaling up efforts at using centrifugation to remove pectin from walnut sap.
Walnut pectin removal, concentration and boiling:
The field site was Mongold’s Walnut Syrup Farm, West Virginia’s largest walnut syrup producer. Gary Mongold has between 700-800 walnut trees tapped. During the 2022 sapflow season he made approximately 13 gallons of walnut syrup. Because it was his first year of commercial tapping, research was not able to be set up until mid-season. At that time, the team installed an Extreme Raw Power (ERP) centrifuge—similar to the one that had been used at Tom’s Creek Maple in the maple syrup clarification experiments—and began centrifuging walnut sap at a rate of 1 gallon/minute. Lab experiments completed in years 1 and 2 of the project had produced a pectin like substance plug and shown that running through an ERP centrifuge markedly reduced the size of that plug. The question this year is whether the removal was sufficient to then concentrate the sugars in the sap with a Reverse Osmosis (RO) unit.
The experiment consisted of spinning the sap at 6,000 RPM at a rate of 1 gallon per minute. The “depectinated” sap was then run multiple times through a Next Generation RO, increasing its sugar concentration from approximately 1 brix to approximately 2.5 to 3 brix. The exact sugar concentrations changed with each sap run. Raising the sugar concentration with two passes through the RO reduced the volume to be evaporated to ¼ the original, cutting Gary’s evaporation time and fuel consumption (he is using a propone evaporator) to a quarter that of running raw sap. This experiment was run multiple times for each sap run for remaining in the season. Having pre and post treatment data allowed the team to document the production savings to his operation.
The results of this work showed that:
- Sap run through the centrifuge could then be concentrated with an RO before boiling. The accepted knowledge was that the pectin would restrict the flow through the RO making sugar concentration not possible. Result: It was possible, it was done at Mongold’s.
- Concentrating the sugars dramatically would cut production time and expenses, making walnut sap and syrup production much more commercially viable.
Literature consulted:
“Analytical tools used for the identification and quantification of pectin extracted from plant food matrices, wastes and by-products: A review.” Antonela Nivcevic Grassino, Francisco J. Barba, Miaden Brucic, Jose M. Lorenzo, Luigi Lucini, Suzana Rimac Brncic. Food Chemistry. 2018.
“A Rapid Method for quantitative Determination of Pectic Substances.” N.P. Shelukhina and L.G. Fedichkina. Actra. Bot. Neerl. June, 1994.
Centrifugation to Clarify Maple Syrup:
Although laboratory results indicated that producers would not be able to completely clarify maple sap with a centrifuge that would be cost effective to a small- to medium-sized maple syrup producer, the possibility still existed that they could remove a portion of the sugar sand (niter) could be removed while still relying on a filter press and diatomaceous earth filter aid to polish the finished product. This would partially achieve the syrup processing and environmental benefits the team had hoped to realize with this project.
It was determined that the modifications to the Extreme Raw Power centrifuge did not result in discernable improvement, therefore no longer justifying the need or cost to develop a syrup-specific centrifuge.
Future Generations University learned that Gary Bilek of Triple Creek Maple in Carnesville, PA has been working with this concept for the last 4-5 years. Gary has installed a centrifuge similar to the ERP machine in the float box between his sap and finishing pans. The project team visited him in the fall of 2022 and learned that by spinning the concentrating sap before it enters his finishing pan that he was able to remove a portion of the sugar sand, and that resulted in a reduction in the amount of filter aid that he is using, keeping his syrup pan cleaner, reducing cleaning time. Gary is an innovative syrup producer, but not a trained scientist. His observations would need to be quantified before any solid claims are made. Towards this end, and at the very end of this Novel Approaches project, one of the project’s collaborating producers—Dr. Keith Heasley PE, of Heasley Homestead Maple— agreed to use the ERP centrifuge and quantify the niter reduction observations. Unfortunately, this work is being completed in the 2023 maple season.
Centrifugation to Remove Pectin in Walnut Sap:
It was concluded that centrifuged walnut sap would not damage the RO membrane, meaning that, after centrifugation, there was no reason not to use the RO to concentrate sugars prior to evaporating walnut sap. RO membranes are expensive, and it was not known if the pectin built up on the membrane surface could be cleaned or if it would degrade the long-term membrane effectiveness. Standard operating practices for the RO were followed by desugaring each night after use with the RO concentrate and soap then washing at the end of the season. (Note: generally membranes are soap washed more frequently, but with less sap being run through, a soap wash was only done after the last sap run.) During each experimental run flows were monitored volumetrically from the RO concentrate and permeate lines while keeping a constant pressure on the RO gauge. Pressure varied by run from 180-200psi but was kept constant during each experimental run. The team did not find a measurable drop in flow rates between experimental runs. At the start of the 2023 sap flow season, the team checked the membrane efficiency by measuring the conductivity of the of the permeate and found it to be less that the recommended limit of 10 micromhos/cm2 showing that it was not passing sugars.
The question that remained was whether the centrifugation process was removing pectin from the sap? The work had shown that sap could successfully run through the RO after it have been centrifuged and had shown that doing so would not damage the RO membrane. But the work had yet to quantitatively prove that in the field was that centrifugation reduced the pectin level in the sap. The problem was that pectin levels in walnut sap were so low that the accepted analytical methodologies were not sensitive enough to detect a change. Hayden Odell at Marshal had tried different analytical techniques with no success. Also, there was still a gel substance in the filtered syrup. However, it was not known how much pectin would be needed for gel formation to plug a membrane filter. And whether enough pectin was being removed to RO the sap but allowing enough to pass to form the gel in the filtrate. Fortunately, the now presumed-to-be-pectin was concentrated in the filtrate gel. This has allowed the team to proceed with investigations the dilute samples would not allow.
Walnut and Maple research beyond the Northeast SARE Novel Approaches Grant period:
Because the field season for sap and syrup production is so short (6 to 8 weeks), it is often impossible to predict and adjust to changes in the application of bench and laboratory research findings before the season is over. In this project, the Future Generations University research team and project partners were restricted to field application in the last year of grant funding. And, because of COVID lab closures at Marshall University and RCBI, it was impossible to be ready for field application until the third year of the project.
The last work on this project was to contract with the Food Science Lab at Virginia Tech to conduct a nutrient analysis of walnut syrup to include a quantification of pectin in the gel filtrate. Unfortunately, not enough of the substance remained from the 2022 season. Future Generations University and field partners anticipate producing quantifiable volumes of the substance in the 2023 sapflow season and having results of analysis in the spring of 2023.
Future Generations University is committed to taking what was learned in the Northest SARE Novel Approaches project and continuing field studies and extension to the sap and syrup industry.
Specific proposed follow-up activities include:
- Quantifying sugar sand removal using an ERP centrifuge.
- Completion of the Virginia Tech pectin analysis in walnut syrup
- A third year of RO studies on walnut sap that has been centrifuged.
Education & Outreach Activities and Participation Summary
Educational activities:
Participation Summary:
2020 Outreach activities, just like the research process, were curtailed by the pandemic. However, RCBI held a new syrup producer workshop in November at Tom’s Creek Maple at which the work of this project was explained.
2021 (year 2 outreach) consisted of two webinars/presentations and the publication of an article in the Maple Syrup Digest on walnut sap flow, that included reference to the pectin issue, and an article promoting walnut syrup production in National Woodlands magazine. Additionally, the team worked on the establishment of a 1,000 tap walnut tapping operation that will be used in the year 3 research.
The first webinar was a presentation and round table discussion with researchers/technical service providers, and farmers/producers participating in current walnut research in the region. The second webinar was directed at the current and potential syruping community through a regular webinar series held monthly by Future Generations University.
Appendix 6 – “Tapping into Sappy Non-Timber Forest Products for Fun and Profit.” National Woodlands Magazine. Autumn 2021. (Appendix 6 Sappy_Rechlin_Autumn2021-lr (1))
Appendix 7 – “Tapping Walnut Trees: Studies in Walnut Sap Flow.” Maple Syrup Digest. September 2021. (Appendix 7 Maple Digest Walnut)
Appendix 8 – “There's Gold in them there Hills” Black gold, that is. West Virginia Walnut Syrup is giving maple a run for its money. Winter edition, West Virginia Living Magazine 2022. https://wvliving.com/tapping-into-traditions/
Cornell Maple Program: Sugar Maple Research and Extension. Podcast: Sweet Talk: All things Maple, Episode 16, Sweet Talk about Walnut Syrup with Mike Rechlin, Maple Commodity Specialist with Future Generations University. August 2022. https://podcasters.spotify.com/pod/show/maple-program.
Learning Outcomes
National Woodlands has a circulation of 46,000. The Maple Syrup Digest is circulated to members of 13 state affiliates, reaching 3,000 syrup producers. It is estimated that at least 2000 producers and 100 technical service providers gained new knowledge and awareness about tappable tree species and alternative uses for walnut trees as well as knowledge about resolutions to solve production issues in walnut syrup.
Project Outcomes
There is a new large-scale (1000 tap) walnut syrup producer in West Virginia as a result of this work; this is the largest producer in the region, and one of the largest in the US.
“It all started at a Friday night social at McDonald’s,” says the owner of Mongold Walnut Farm. “There’s a group of us men that get together every so often to just shoot the breeze. On this particular Friday, my buddy [who makes maple syrup] told us that, if anybody knew of folks with some walnut trees, Future Generations University was looking to experiment with walnut tree tapping—and walnut syrup was selling for around $500 a gallon, as opposed to maple syrup that was selling for only $40 a gallon. You could say that piqued my interest... I’m a self-employed mechanic, and I don’t have a 401(k). This is my retirement plan.”
The project team continues to provide support to new and existing walnut syrup producers in
As the project moved forward in 2021, work pivoted to focus more on walnut sap and pectin. The reasoning behind the pivot included that by 2021 February, walnut sap-flow season was underway and there was a ready supply of fresh sap to experiment with.
The Marshall University team, Kolling and O’Dell, worked with other faculty in the chemistry department to come up with analytical procedures to measure the amount of pectin in the sap. Meanwhile, Greg Christian (Toms Creek Maple), tapped walnut trees and collected the sap for further analysis. After the second and third years of work, the team has concluded that the complete elimination of all niter compounds will not be possible using centrifugation. Depending on the site and the conditions under which the syrup is made, particles imparting cloudiness to syrup vary down to the point of being almost colloidal. Although centrifugation is theoretically possible, it is not practical or cost effective with a reasonably priced off-the-shelf centrifuge. It is believed that is it possible to remove the vast majority of the suspended particles but that the syrup will need to be polished using standard filtration techniques. In the last year of project, activities planned include determining the percentage niter that can be removed with a centrifuge and the reduction in the use of diatomaceous earth that results from centrifuging syrup prior to filtration.