To Vent or Not

[MaineMapleDave]

I know this has been addressed before, but there does not seem to be a clear consensus, so thought I'd bring it up for more discussion.

I have groups of trees that do not produce much sap and are hard to get to, so I have created 5 mini-pipelines. Basically, laterals with 3 to 5 taps feeding into it.

The land is fairly flat, so I introduced as much pitch into the lines as I could, and the buckets that they drain into are all as low as possible (actually on the ground, but sort of buried in snow right now!). The longest lateral is probably 25-30 feet from the first tap to the downhill bucket.

There is sap in the buckets. There is sap in the lines, but it seems like the only thing driving the sap through the lines is pressure from the tree and a bit of gravity.

There's no way that I have enough pitch to introduce any sort of natural vacuum, nor is the sap flow ever going to be that great.

Sooooo...... would I increase the sap flow if I vented the laterals at the farthest "uphill" point, or would I be wasting my time?

All advice kindly appreciated........

[WESTVIRGINIAMAPLER]

I think you may increase the production some, but hard to say without seeing setup. If the gas is building up inside the lines, then it will decrease the flow.

Experiment with it and see what works best! :D

[mapleman3]

can't hurt to try, you can always plug the vent later, at the highest point add a tee with a 5/16 line for a vent.... who knows right?

[WF MASON]

I've heard the argument both ways , natural vacum created by the flow of sap through the line , lamb does make the vented spout , I've seen many people use these on the last tree out to vent the line. One guy up in Derby used a small drill bit and drilled the side of head of the last tap out.
Vent or Not.
Dropped or Raised , we may never know.

[themapleking]

Natural vacuum is there such a thing :?: Has any one ever installed a vacuum gauge at the mainline to see if there is vacuum :?: I never did until I installed a vacuume pump system.
Just wondering if any one has done it :?

[mapleman3]

try sucking on a vac gauge tube... no way, can't move the needle... ok I admit I tried :lol:

[themapleking]

Thats because your a man :oops:

[mapleman3]

aint that the truth... like the red button they tell you NOT to press :lol: :wink:

[WESTVIRGINIAMAPLER]

I don't think there is such a thing as natural vaccum in tubing unless the grade is steep and the line is continuously full of sap to pull a vaccum.

You will never convince me that tubing without vaccum will run as much as buckets. :?

[mapleman3]

Brandon, I have to agree with you on that, Barton St never ran for me last year, 100 taps, 3/4" main at least 3-4% grade, just didn't do it, maybe more grade would have helpd on the laterals... who knows, once I find another Vac pump and mechanical releaser for next to beans I will run that bush... but not on "natural" vacuum

[themapleking]

I agree with that. When I first installed tubing I got about half the sap than when I had buckets.
But after the vacuum pump I'm getting about twice the sap compared to buckets. Got another 625 gals today. Glad I'm on vac this week. Looks like we're going to get all the sap this week.

[WESTVIRGINIAMAPLER]

With the sap I ran on the ground and the syrup that got ruined by my dad in the pan, I would still be around 1 quart per tap and it wasn't a great year, but a fairly good year. I have aproximately 25 taps that are on small trees and that run very little. I will probably only tap these every other year. They didn't produce much, but every little bit helps. I really was only at 400 taps this year, but I did get some sap from the other 25, but not very much. :? Both of these two groups of trees that make up the 25 taps are right in the perfect location of my tanks or I wouldn't fool with them. :?

[Vermonster]

Vented versus Closed 5/16” Tubing: It is widely recommended that tubing systems be closed rather than open or vented. It is
common to see 5/16” lines full of sap that appears to be stagnant. It is true that when the end spout is pulled on a so-called stagnant
line the sap will drain out rapidly leading producers to believe that lines need to be vented to allow them to drain properly. After
close observation, vented lines move a little sap and a great deal of air very rapidly while closed lines move at a reduced rate yet
produce much more sap due to the fact that they are moving sap and not air. The stagnation effect is an illusion. While sap runs
faster through vented compared to non-vented tubing systems, venting of tubing resulted in a 32% loss of sap production, probably
due to faster drying of tapholes and loss of natural vacuum on slopes. Stowe Isselhardt NAMSC
http://www.uvm.edu/~pmrc/Research05.pdf

[brookledge]

I have to agree that proctor's results make the decision easy
no venting.
But I can't test it for myself because I'm all vacuum now.
Everybody should read all the test results that they have done. Case in point was the issue a few months ago reguarding buying used tubing and reusing it. Proctor has tested and found over two years a loss of 10 to 30 percent of sap. I know that buying new tubing is more expensive but if you make 10 to 30% more syrup then it will pay for itself.
Many more interesting test that they have done.
Keith

[Vermonster]

they sure have ..... they also have dispelled many a myth.
I found their research about spouts (sizes, placement, etc. ) and tap hole depth as it relates to harvest and damage most interesting.
Thanks ....

[treefinder]

i tell you what guy's i just went to leader today to pick up my new steam hood. and i asked fred about vented spouts and he said to throw them away! he said it has been proven that the flow is slower and the tubing will make like a back suction on its own .. beleave or not thats what they say.i have some vented spouts and i'm going to use them anyways but i wouldn't go buy any i'll just plug the hole..

[powerdub]

Do not vent. I have seen sap go up hill as much as thirty feet and out the top. That is, a vetical feet, straight up a vented line. Path of least resistance is all I can explain. If you have one or two sags in your mains, and they don't need to be big sags, just enough to make a trap, then the sap will run out the other end. no one is perfect and niether is thier tubing system. Don't vent. take it or leave it.

[H. Walker]

Check out this site on venting. Granted the testing was done in the 70's, I don't think the physics has changed.

www.nysaes.cornell.edu/pubs/fls/OCRPDF/FLS-014.pdf