How Not to Test a Sap Transfer Pump

by Tig Tillinghast

That column of water on the left is hitting the ceiling and showering down all over the vacuum room. I had the clever idea to test to see if I’d hooked up the correct plugs by flicking the sap extractor’s electronic trigger. Well, it worked to show me the plug was in the wrong place. Always good to have someone capturing the moment, too.

Today’s run was very, very small. Just enough for a nice shower. Trees are still deeply cold, although tomorrow’s predicted warm rain might change that.

Ellie and I patched up enough vacuum leaks out in the forest to get the Strafford bush up to about 20 bars of mercury. That’s about as high as I want to go. 30 bars of mercury is the vacuum of space. 21 bars of mercury is about where researchers have shown harm can be done to the maple trees (this, despite the fact that the maple equipment dealers insist that 24+ vacuum systems are harmless – they must just know it in their bones). 20 bars is just about right.

Here’s the scale to go by…

0-13 bars – Not much happens (although sufficient for sap ladder construction)

13-15 bars – You might see 125 percent the normal amount of sap

16-19 bars – You’d probably expect to get half again as much sap as you’d get without vacuum

20-21 bars – You might get 180 to 200 percent of the normal sap flow

22-24 bars – Maple equipment dealers get a warm fuzzy feeling. The trees show larger internal staining.

25-29 bars – Maple logs come screaming down your main lines

30 bars – You are in orbit, and you’re unlikely to be making maple syrup

Back in Thetford Center, I got the vacuum system up and going. It started off at 7 bars, which is par for the course. It’s always interesting to see where it’ll settle at first, once the ice melts for the first time in the year. I was able to patch lines (why in the world would a deer want to chew a sap line when my wife’s perfectly good apple saplings are right next to them?) and see the vacuum level rise to 10 bars before it got too late. We’ll get that forest up to 19 or 20 bars by sap time tomorrow. I don’t even want to calculate how far I’ve trudged in deep snow today with tens of pounds of tools on my back. When Spring flirts with us again tomorrow, bringing with her a bevy of sap, it’ll all be worth it.