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Efficiency Checklist

September 21, 2018
  • General rule of thumb is to keep the sap depth about 2 inches deep. This will keep your pans and syrup safe. Running the pans deeper than 2″ demands more from your fire and it will not boil as hard.
  • Consider preheating your sap before it enters the evaporator pan. (ie. Feed Pan or Preheater)
  • Forced Draft will be more efficient than natural aspiration and will allow you to burn firewood that is less than prime. To maximize with natural aspiration, adjust the Draft (Located under the Firebox Door) to make sure the fire is receiving enough oxygen.
  • The bed of your arch should raise up to be within 1″ from the bottom of the pan/flues in order to force the heat into the pans/flues. (Not applicable to StarCat, Dauntless evaporators. Corsair evaporators include an optimizing bed riser when applicable.)
  • Your pans’ construction also greatly influences efficiency. More flues = more of the pan’s surface area coming in contact with the fire = higher efficiency. Also, the thinner the stainless steel is, the better the heat transfer. (That is why Smoky Lake uses 22 ga. stainless steel. It is more efficient than competitors’ 20 ga.)
  • If using a wood-fired arch, use well-seasoned hardwood, and cut to smaller diameter. This is by far the most common culprit to a weak evaporation rate. See links for more details.
  • If using a wood-fired arch, make sure to add more fuel at consistent intervals. Keep the fire HOT. Corsair evaporators include a Peep Window that allow you to monitor what’s happening in the firebox.
  • Add raw sap to the pan in a consistent trickle. In contrast, adding large dumps of sap by hand will kill the boil.
  • If you have a continuous flow pan, do NOT scoop or mix the sap in the pan. Let it move through the system on its own. Control foam with a drop of canola oil, and NOT by scooping. Scooping/mixing will mess up your density gradient.
  • Reverse Osmosis Systems can concentrate your sap so there is far less boiling time.
  • Your Stack Pipe needs to have sufficient draw. The minimum height is generally 2 times higher than the length of your pans, up to 12 feet. For example, a 2 x 4 pan would need 8 feet of stack pipe. The base stack is counted as part of that height. If height is sufficient but you are still having problems with the draw, see our article about back draft. Also, make sure the stack pipe is clear of any debris.
  • Use Rail Gasket between your evaporator pan and your arch. This prevents cold air from being sucked into the firebox and cooling the pans. Stiffened Gaskets (applicable to Corsair and Silverplate evaporators) span the width of the arch and also help seal up openings for the same reason.

Related Articles

Understanding Stack Temperature

How To Get The Most Out Of Your Firewood

Flat Pan Vs Divided Pan