MAPLE SIRUP PRODUCERS MANUAL 



PN-4703 



Figure 7. — This grove shows the effect of heavy grazing, a 

 practice not recommended since it results in reduced 

 sapwood production, stag-headedness, loss of reproduc- 

 tion, and root damage caused by soil compaction. 



PN-170-1 



Figure 8. — Removing overmature trees that produce sap 

 low in sugar content, to encourage growth of young 

 stock. The high cut is made to avoid some of the sap 

 stain and diseased wood associated with old tapholes. 



tree. A mean range per taphole is from 5 to 15 

 gallons {95). However, a single taphole often 

 produces from 40 to 80 gallons of sap in a single 

 year — the equivalent of 3 or more quarts of 

 sirup. 



The sugar content of the sap produced by 

 different trees in a grove varies considerably 

 (45, 110). The sap produced by the average tree 

 has a sugar content of 2° to 3° Brix.^ Frequently 



' The density of sap and sirup is due to a mixture of 

 dissolved solids and not just to sugar. The physical in- 

 struments used to measure the density of sap and sirup 

 do not distinguish between the density due to sugar and 

 that due to other solids. The degrees Brix (° Brix) means 

 that the solution has the same density as a solution 

 containing a percentage of sugar numerically equal to the 

 Brix value. 



trees produce sap with a sugar content of less 

 than 1° Brix, and occasionally a tree produces 

 sap with a sugar content of 9° or even 11° Brix. 

 A conservative estimate is that the sap from 

 four tapholes will yield 1 gallon of sirup. This 

 sap most likely would have a density of 2.2^" 

 Brix. Thus, 10 gallons of sap from each taphole 

 would be required to yield 1 gallon of sirup. 



No device has been developed that will enable 

 a maple sap producer to determine when sap 

 will begin to run. However, sap will flow from 

 the tapholes over a period of several weeks. The 

 greatest yield of sap may be produced in a 

 single run that occurs at the beginning of the 

 period, at any time during the period, or at the 

 end of the period. In 1960 almost all the sap 

 crop was collected in a 24- to 48-hour period and 

 the Brix value of the sap was much higher than 

 2.2°. Many producers reported sap of 5° Brix 

 and higher. Because of the large volume of sap 

 collected in this short period, many producers 

 reported that their buckets overflowed. How 

 much was lost will never be known. This loss 

 would not have occurred had plastic tubing 

 been used for collecting and transporting the 

 sap. 



Because of the large yield of sap in 1960 and 

 its high sugar content, many producers who 

 sold their sap to central evaporator plants re- 

 ceived as much as $1.90 per taphole. A yield per 

 taphole of 10 gallons of 5°-Brix sap having a 

 value of 19.5 cents per gallon gives $1.95 per 

 taphole. On this basis, a sugar grove with only 

 100 tapholes per acre would produce a gross of 

 $195 per acre. This may answer the question 

 that has often been raised as to whether the 

 sugar orchard should be operated to produce 

 sap or should be cut and sold as lumber. 



The yield and sweetness of the sap produced 

 by a tree vary from year to year, but trees that 

 produce sap with a high sugar content and 

 trees that produce sap with a low sugar content 

 maintain their relative positions from year to 

 year {112). It is important to know the exact 

 sugar content of the sap produced by each tree. 

 Measuring the sugar content of sap is not 

 difficult. All that is needed is a sap hydrometer 

 or refractometer and a thermometer. 



To make the reading, float the hydrometer in 

 the sap bucket or in a hydrometer can contain- 

 ing the sap (fig. 9). Also, obtain the temperature 



