+ Reply to Thread
Page 2 of 2 FirstFirst 12
Results 11 to 16 of 16

Thread: maple research

  1. #11
    Join Date
    Mar 2020
    Location
    Springfield, MA
    Posts
    12

    Default

    Has there been any research on the effects of localized water quality issues on sugaring? Some examples like a high sulfur content in the water (like in the Moosehead Lake Maine area - filters required for drinking water at the cabin we rent in the summer) , having a property next to but uphill from a transfer station (nice piece of land for sale), or in areas where perfluorinated carbons, better known as PFAS had been used in firefighting foam (this is a local issue impacting fresh water drinking wells surrounding our National Guard Airbase now), or even former farming pastures.

    I've Googled a bit and can't seem to find anything about that sort of thing. I assume the impact would be a negative to sugaring, but with all the boiling perhaps that removes the issues normally associated with drinking it straight.

  2. #12
    Join Date
    May 2015
    Location
    Vermont
    Posts
    5

    Default

    I have 2 questions. 1 is related to equipment and the other related to production.

    Equipment related question.
    Has there been a test done using water to water heat pumps relating to increased productivity in the RO field? Raw sap goes through an RO faster when it is warmer, so it would make sense that if water (raw sap) was pre-heated with a heat pump using the rejected heat to cool the concentrate you could both increase the production time of your RO and by volume have cooler concentrate than the raw sap coming in. This may sound like an odd question, but if the manufacturers could offer this as an add on to any RO than for the people that are outgrowing there current RO would have another option that would be less expensive than buying a larger on. Specifically in this study I would be interested to see if spoiling time changes, and what the bacterial growth would be. With the technologies in the heat pump field over the last 10 years this may end up being a savings in electricity as well (it is on paper but real world testing always proves a little different)

    Production related question.
    I understand that high vacuum is proven. To my understanding (please correct me if I am wrong) is because it changes the barometric pressure in the tree. Has there been a study done on varying the vacuum level throughout the day to see if increasing and then reducing the barometric pressure in a tree actually changed production?

  3. #13
    Join Date
    May 2009
    Location
    UVM Proctor Maple Research Center, Underhill Ctr, VT
    Posts
    5,025

    Default

    Quote Originally Posted by Aaron Stack View Post
    Has there been any research on the effects of localized water quality issues on sugaring?
    It depends almost entirely on the substance in question. PFAS compounds don't seem to be taken up by trees. Neither is lead. Some pesticides are translocated systemically in the tree. The best answer is that it depends upon what substance/pollutant you are referring to.

    Turns out this response is my 5,000th. I'm no Dave Klish (maple flats), but seems like a good bit to me.
    Dr. Tim Perkins
    UVM Proctor Maple Research Ctr
    http://www.uvm.edu/~pmrc
    https://mapleresearch.org
    Timothy.Perkins@uvm.edu

  4. #14
    Join Date
    May 2009
    Location
    UVM Proctor Maple Research Center, Underhill Ctr, VT
    Posts
    5,025

    Default

    Quote Originally Posted by ecp View Post
    Equipment related question.
    Has there been a test done using water to water heat pumps relating to increased productivity in the RO field?
    I assume you mean heat exchangers? If so, we did some work several years ago using hot water off the Steam-away to preheat incoming sap. It raised the efficiency by a good amount. I do know some sugarmakers who have used heat exchangers to preheat sap before the RO and thought it helped a good bit. There is no question that it would help increase RO efficiency, and if used on the concentrate side, would cool the concentrate. The real question is whether the additional cost would justify the expense of the exchanger and the added plumbing required. Probably not for small-moderate producers, but for larger operations it might well be worth it. But the answer to your specific question is "no", I don't know of any research on the subject pertaining to sap/concentrate specifically.

    Production related question.
    I understand that high vacuum is proven. To my understanding (please correct me if I am wrong) is because it changes the barometric pressure in the tree. Has there been a study done on varying the vacuum level throughout the day to see if increasing and then reducing the barometric pressure in a tree actually changed production?
    Sap moves in response to pressure gradients, from areas of high pressure to areas of low pressure. You can think of it as water running downhill. The steeper the gradient, the faster the sap (or water) will flow. By artificially increasing the gradient from the inside of the tree to the outside of the tree (within the tubing system using vacuum), you make the sap run out faster and can pull more of it out within a flow period. Pulsation of the pressure (increasing and decreasing pressure within the tree or the tubing system) will not produce any beneficial effect.

    Vacuum is a weird thing. It simply means "below atmospheric pressure", and so we have to phases we think of: pressure above atmospheric (which the tree is in immediately upon thawing), which is thought of in PSI, and vacuum, which is pressure below atmospheric, measured in inches of Hg, but really in terms of physics there isn't that distinction. It is simply pressure on a continuous scale. The pressure in a tree is high right after thawing, and falls to a lower pressure as the sap flows out until it equilibrates with the external pressure...either the pressure of the atmosphere (for gravity collection) or the pressure in the vacuum tubing system.

    The actual difference in gradient is important as this will dictate how much sap will flow out after a sufficient period of time. If the vacuum is high enough, sap flow might not stop, but you'll enter a phase where water can be pulled from the ground, into the roots, up the stem and out of the taphole. Sap sugar will steadily drop when this happens. The strength of the vacuum also influences flow RATE. This comes into play when you have periods during which the thaw is not long enough to fully equalize the pressure in the tree to the outside. Another analogy -- a garden hose. Turn it on a little (low pressure) and it'll take a while to fill a tank. Turn it on full blast (high pressure) and the tank will fill faster. If there is a steep gradient (because of vacuum), then the sap will flow out faster during a short thaw and you'll get more sap before the spigot is shut off by a freeze.

    Finally, given a long enough flow, with vacuum, the pressure on the inside of the tree will get low, that is...get below air pressure, and you can have vacuum develop WITHIN the tree. This isn't bad for the tree -- the xylem (wood) in trees is under negative pressure most of the time when there are leaves. But "vacuum" or pressure below atmospheric does "get into" trees on vacuum systems if the thaw is long enough. This probably actually enhances water uptake during the freeze period.
    Dr. Tim Perkins
    UVM Proctor Maple Research Ctr
    http://www.uvm.edu/~pmrc
    https://mapleresearch.org
    Timothy.Perkins@uvm.edu

  5. #15
    Join Date
    Mar 2020
    Location
    Springfield, MA
    Posts
    12

    Default

    Great to hear on the PFAS compounds - I won't have to change my plans for next year.

  6. #16
    Join Date
    May 2009
    Location
    UVM Proctor Maple Research Center, Underhill Ctr, VT
    Posts
    5,025

    Default

    Quote Originally Posted by Aaron Stack View Post
    Great to hear on the PFAS compounds - I won't have to change my plans for next year.
    Note that I cannot certify that there is no PFAS in your or any particular syrup without it being tested, however in the testing that the Vermont Department of Environmental Testing did of maple syrup made from trees within the area of concern, PFAS was below the detection limit.

    https://vtdigger.org/2016/04/13/mapl...on-tests-show/

    https://dec.vermont.gov/sites/dec/fi...ts.N.Benn_.pdf
    Last edited by DrTimPerkins; 06-23-2020 at 08:08 AM.
    Dr. Tim Perkins
    UVM Proctor Maple Research Ctr
    http://www.uvm.edu/~pmrc
    https://mapleresearch.org
    Timothy.Perkins@uvm.edu

+ Reply to Thread
Page 2 of 2 FirstFirst 12

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts