334 Bulletin 167 



its duration depend upon weather conditions. The sap is more 

 likely to flow in the daytime than at night; and the more im- 

 portant runs are confined to what are spoken of as 'good sap 

 days.' These occur only after the air temperature has remained 

 below freezing for some time. If, following such a cold spell, 

 the temperature rises materially above 32 F. a good run is like- 

 ly to ensue. Excessive warmth and high winds check the flow. 

 Freezing nights followed by moderately warm, cloudy days, and 

 the absence of excessive sunshine and heavy winds, are the 

 meteorological conditions which characterize the best sugar 

 weather. So long as the air temperature remains essentially 

 constant, whether warm or cold, little or no sap is obtained." 



"The buckets in which the sap is caught are made of wood, 

 tin, or galvanized iron; and, in the better works, are covered to 

 keep out rain, snow and other foreign material. The sap is col- 

 lected after each day's run ai?d taken to the boiling house, tech- 

 nically known as the sugar house where it is concentrated into 

 sirup in large shallow pans over a n?. arui §' wood fire as rapidly 

 as the capacity of the equipment will permit." 



"Maple sap is a sweet liquid containing a varying amount, 

 averaging from 2 to 3%, of sucrose, and, usu^ 11 ^ traces of in- 

 vert sugar. In addition to these carbohydrates it-- contains small 

 amounts of proteids, of mineral matter, mainly lime\ and P otasll > 

 and of acids, mainly malic acid. The sap of the earliei" flows is 

 water clear and transparent, and possesses a clean, sweet / avor - 

 With the advance of the season, however, it undergoes a ma\O rked 

 change. As the days grow warmer and night freezes are k° ss 

 severe and less frequent, the sap gradually becomes cloudy am 1 

 discolored and unpleasant flavors develop. Such sap 'while 

 usually containing only the normal amount of acid, is popularlv 

 termed -sour.' It rapidly deteriorates when stored even for 

 a few hours. Several types of sour sap are recognized by suw 

 makers, to which the descriptive terms 'milky,' 'stringy ' 'red ' 

 and. particularly, 'green" are commonly applied. Green' sap is 

 almost always secured just before the close of the season, when 



