Taps

[BigPine]

I have a mix of taps, but over the years have gone mostly to the "tree saver" taps with the check valve (little ball in it).
I am exclusively drop lines to buckets.
Without looking, I think the "tree savers" are 5/16".

Is there a "vented" version of plastic taps?
Looking at a receipt from Leader in 2012 I bought 10 taps ... item #4778S description ...Spout UNVENTED 7/16".

What about when you go with Drop lines to a mainline and it is gravity only (no vacuum), should the line be vented?
Any input will be appreciated.

[TerryEspo]

Hello BigPine:

Don't vent.


Terry

[maple flats]

At one time venting was done, but testing soon showed that venting was a bad idea. The tap holes dry up sooner when vented and you get less sap.

[BigPine]

At one time venting was done, but testing soon showed that venting was a bad idea. The tap holes dry up sooner when vented and you get less sap.That is what I thought I read somewhere. Does that mean the 'check valve' type taps will produce more sap - for the same reason?
This is a lot of questions, but - the 'check valve' taps I have are 5/16". My other taps are 7/16". Why not have 7/16" with a check valve? How does hole diameter come into play?
Appreciate any input.

[Thompson's Tree Farm]

That is what I thought I read somewhere. Does that mean the 'check valve' type taps will produce more sap - for the same reason?
This is a lot of questions, but - the 'check valve' taps I have are 5/16". My other taps are 7/16". Why not have 7/16" with a check valve? How does hole diameter come into play?
Appreciate any input.

The internal scarring in a tree tapped with a 5/16 hole is about 1/2 that of a 7/16 hole. Studies show yields with 5/16 under gravity are about 95% of 7/16 yield and about equal if the tree is under vacuum. 95% of the sap with half the tree damage is a no brainer.