Vacuum idea

[Ittiz]

So I've been sugaring for a couple years now as a hobby. One of the types of trees I tap is birches, but their sap burns easy and it's only 1%. Anyway I made a vacuum still (can pull 29.9" of Mercury at sea level at about 3cfm) partly to boil the sap at a lower temp so it doesn't burn. At the moment the max batch I'd be able to do is 2.5 gal of sap, not a lot.

I hadn't heard of the idea of using a vacuum line to pull sap out of the trees until I came on here. It gave me an idea. Why not attach a vacuum line directly to the trees from the vacuum chamber? Run it at around 28" of mercury. At that pressure the sap would stay fluid while it was traveling the cold line. Then when the sap entered the vacuum chamber it would be heated to about 80F at which point the water would boil away. Eventually the vacuum camber would fill with syrup. I'd probably still need one large vacuum chamber for the waste water, it's not good to run steam through the pump. I probably wouldn't try an implement the idea till next year at the moment I'm doing regular tubing into a 55 gal drum. I've never tried vacuuming directly from the trees so anyone see any flaws with my idea or any input?

[Scribner's Mountain Maple]

I'm not sure about using Vac to produce sap into Syrup. I do know that Mike Farrell from Cornell research told me that he didn't see any additional affect from using Vacuum on Birch trees to increase production. Essentially to me, what he was saying was that using Vac for producing Birch Syrup is not needed. However, using an RO is.

Works good for Maples however. Good luck.
Ben

[Ittiz]

The point is the lower the pressure the lower the boiling point. With the right set-up most vacuum pumps could boil water well below 212F. I've already used it to boil water at about 60F. The big thing is I don't like wasting propane to boil the stuff, and it's a fire hazard. Which lead to me looking for a low temp route. Not RO, I already experimented with that and was not happy with the results and the price was high.

[325abn]

I believe I have read about using vac to boil maple. Maybe in an old Maple Producers manual??

[BreezyHill]

I recall seeing something about pat of maples flavor is from caramelizing of the sugar, that requires higher heat than 60-80. I don't see a problem with the concept but the fesability of having that large of a container to " cook the product".

But...what about using a zero tank to get to 20" of vac and using a wood boiler to heat the container thru the old vacuum coils in the vessel?

I plan on trying to dry some wood this summer using a vacuum kiln consisting of greenhouse plastic and a pump.

For several years we vacuumed our corn silage pile to pack it and pickle it. It worked great and cornell did research in the 1960 and earlier about this. The vacuum would produce more weight per sq inch than any tractor around.

So I would seal the wood in the same way we did the silage with 6-8 inches of gravel on top of the plastic edges around the wood pile.
Clear plastic will allow the sun to heat the wood and the vac will pull the moisture out.
We located a plastic pipe in the pile of corn and got very little moisture from the 70% silage so I think most of the water wood settle to the ground rather than into the pump. A fan on the pump would be a must if having to run high vac in summer heat. But a vfd may keep the pump cool since you only need to drop the vac and maintain on a leak free system.

Ben

[Ittiz]

BreezyHill,

Well I guess vacuuming the sap might produce a lighter flavor, "Grade A Ultra Light" I suppose at least for early season.

The issue with vacuuming boiling a large amount of anything is the pressure from the weight of the substance. As something gets deeper the weight increases the pressure, so only what's near the surface will boil after a few inches of depth. Also if your trying to dry something there are other considerations. I put a live plant in my vacuum chamber at near vacuum for an entire night once. In the morning I checked it and it wasn't even wilted. This is because of the turgor pressure inside the plant was high enough to keep the water from boiling away. Also the plant can detect conditions of increased evaporation and close its stoma to prevent water from escaping. Another thing is of course I wasn't running the pump all night, so as the water evaporated from the plant it increased the pressure in the container.

Anyway from what I can see as long as the concentrated sugar doesn't prevent the water from boiling at low temps once it get concentrated down I should be good. Even if it does it should remove the vast majority of the water before that happens.

[lpakiz]

But you still must expose the sugar to heat higher than (guessing here) 212, or maybe as high as 219, at least for some period of time. An RO can get your sap to 67 brix, but there is no taste other than sweet, because maple sugar must carmelize, and adequate heat is the only way to do this. However, this could be used much in the same way an RO, to reduce the amount of water you need to boil off.