Gravity tubing system and vacuum question

[ploefstedt]

Hi all-

I have a small setup, with 3/4 " mainlines (2), excellent consistent slope, laterals handling no more than 11 taps per, and only 55 total taps/35 taps on
each mainline piece. Everything is good and tight, sag free, and looks
picture perfect. However, I noticed yesterday that the sap was splurting
out of
the mainline into the barrel; instead of a consistent, smooth flow, it was more like trying to get those last fews drops out in the men's room (sorry for the analogy, but a picture is worth a thousand words).

There is no air at all coming into the laterals or mainline, except at the barrel. I am appalling bad at visualizing these things, but I can't seem to get straight in my mind whether I should be letting air in at the top of the mainline, or trying to keep it all sealed up like this. I keep thinking of the straw in the soda can trick - put your finger over the top, and the soda stays in the straw; remove it (introduce air) and it flows out. Why is my mainline not like the straw?

Any advice welcome! I had expected boo-coo sap yesterday from the line
with the 55 taps, instead I got perhaps 28 gallons.

Many thanks -

Paul Loefstedt
Bedford NH

[maplecrest]

my thoughts are the trees need time to warm up. what did the sap test for sugar content?

[WESTVIRGINIAMAPLER]

Trees put off gas and maybe quite a bit yesterday and the gas was likely causing that.

[royalmaple]

Your main lines are already "vented" the end the sap comes out of is not allowing it to vapor lock in a sense. If you are not running full pipe then it's just the way it is, until you get stronger runs. You may have some slight sags and the sap is building up, then over the threshold of the sag and it kinda siphons the sap out of the sag so that is your rush of sap.

[gmcooper]

28 gallons sap out of 55 taps is not bad for this early in season. Your weather may have been better than ours yeasterday but we only hit 42 and the wind picked up in the afternoon which would certainly cut down the sap flow. Seems a little early to be tapped in your area but maybe your trees are in a warm location. The spurts and small gushes are quite common to see on gravity.

[maple flats]

Do not vent the top or any place. You have a natural vacuum and that is good, it helps get more sap/tap. Leave it like it is.

[ploefstedt]

I appreciate the input...I will wait it out and hope for the best, and
not mess with anything!

Cheers and happy sapping to all -

Paul L.

[Russell Lampron]

With that number of taps on a 3/4" mainline you are not going to get a large volume of sap. My math comes up with 70 taps if you have 35 on each. For as windy and cool as it was here in Loudon yesterday that doesn't sound too bad for this early in the season.

Russ

[Gary in NH]

Hi Paul,

How much sap did you end up with this week? Let me know if you need some help. I'm waiting a little while longer before I tap.

Gary

[3% Solution]

Hi Paul L.,
Won't worry to much about it, still kinda early.
We have two lines on 1/2" mainline, 20 on one, 27 on the other.
They are closed at the top.
Remember, if your mainline is open at the bottom there is air flow up the pipe, because you can't have a vacumn in that situation.
Both run real good when the sap's a flowing.
I would say they run about the size of the lead in a pencil.
That doesn't seem like much, but let that run for 5 or 6 hours and you got some sap.
Did you check your sugar content?
Hey if you need a 2x6 you need more taps, like another 80 or 90!!!!!!!!!!!

Dave

[Uncle Tucker]

What might be happening is like on the windshield of a car that when the drops start off it is slow, but when those drops run into other drops they speed up. That’s why it might cycle.
Who Knows? As long as your getting sap this early in NH I wouldn’t care how it gets there.