As a result of interest exhibited by maple producers, a study was established in 1999 at the Uihlein Field Station to evaluate sap volume yield, sap sugar concentration, rate of taphole closure, and amount of discoloration zone associated with use of the small diameter spout compared to the traditional spout.
Small diameter is on the left.
The study consisted of 80 taps in replicated lines of 10 taps each installed in the Uihlein Field Station sugarbush. Vacuum levels were maintained at 15 to 18 inches of Mercury at the tap. To reduce the effects of tree variation, the spout treatments were alternated between years. Overall results of the two year study suggest sap volume yield under vacuum from small diameter spouts is comparable to that of conventional spouts. For the two year study, no significant difference in sap sugar concentration was noted for sap collected with small diameter spouts and conventional spouts.