116 



AGRICULTURE HANDBOOK l.'?4. U.S. DEPT. OF AGRICULTURE 



Table 17. — Key for interpretinx) results of color test for invert siigar content of five dilutions of 



maple sirup 



[- indicates negative reaction; + indicates positive reaction; ♦ indicates doiibtlul reaction! 



Reactions for 5 test dilutions 



Invert-sugar content of sirup 



Suitability of sirup for making into 

 cream 



Percent 



Less than 2 Suitable. 



More than 2, less than 3 Suitable. 



More than 2, less than 4 Suitable if sirup is heated 2 to 4 



degrees higher than usual in cream- 

 making. 



More than 3, less than 4 Not suitable. 



More than 3, less than 5 Not suitable. 



More than 4, less than 5 Not suitable. 



More than 4, less than 6 Not suitable. 



More than 5, less than 6 Not suitable. 



More than 5, less than 7 Not suitable. 



Above 6, may be 7 or more Not suitable. 



THE CErNTRAL EVAPORATOR I'LAINT 



Before 1955 no market existed for maple sap. 

 The sap crop had to be converted to sirup or 

 some other product on the farm where it was 

 produced before it became marketable. Maple 

 sap, therefore, occupied a unique position in 

 American agriculture because all other farm 

 crops are marketable as produced. 



This practice contributed little toward devel- 

 oping the maple industry or toward moderniz- 

 ing sap production to make it competitive with 

 dairying, stock raising, or gi-ain farming. 



The cuiTent trend toward central evaporator 

 plants (figs. 124 and 125) has marked a new era 

 in the maple industry. No longer do all sap 

 producers have to be skilled sirupmakers; in- 

 stead, the central plants are operated by and 

 staffed with specialists not only in sirupmaking 

 but also in marketing. Other advantages of- 

 fered by the central evaporator plants are: 



(1) The central plant eliminates the former 

 duplication on each farm of invested capital for 

 evaporator and related equipment and for an 

 evaporator house. 



(2) The farm plant often was too small to be 

 operated economically and was wasteful of la- 

 bor. A small evaporator having an output ca- 



pacity of 1 to 5 gallons of sirup per hour re- 

 quires as many man-hours for its operation as 

 does the central evaporator plant that produces 

 15 or more gallons of sirup per hour. 



(3) Thousands of farmers with stands of ma- 

 ple trees that they had not previously used for 

 sap-sirup production now find it practical and 

 economical to produce and sell a sap crop. 



(4) A more uniform and better quality prod- 

 uct can be produced in a central plant. This 

 tends to stabilize the market. 



PN-1S20 



Figure liJ,. — This central evaporator plant at Ogema, 

 Wis., has one evaporator. 



