Micro-organisms of Maple Sap IT- 



. Summary 



i. All inoculating- organisms used ( with a single ex- 

 ception, sirup number 12) had previously been obtained from 

 'maple sap and the so-called natural infection due to carel< 

 methods of gathering and handling may result in the introduction 

 of any or all of the organisms employed in this investigation, 

 with similar results as regards quality of product. 



2. The conditions are more favorable to bacterial, yeast and 

 mold contamination in the sap toward the close of the sugar 

 season than earlier because of the higher temperatures, bare 

 ground, rain, interrupted runs, less cleanly utensils, etc., which 

 then obtain. 



3. The relation of cleanliness in all operations and of 

 promptness in collecting and boiling the sap to the maintenance 

 of a high quality of product are strikingly shown by the results 

 secured in this investigation. 



4. The several forms of micro-organisms used in this study 

 exerted apparently little or no effect on the ash content or the 

 malic acid value of the sirups. 



5. Slightly low ash contents and malic acid values were 

 often obtained on individual samples of the better grades <>t 

 sirup, which, however, represented the product from but a few 

 trees. They occurred mainly when increased concentration be 

 yond the eleven-pound gallon standard was followed by a pro 

 longed sedimentation or thorough clarification. 



6. The deficiencies noted in ash contents or malic acid 

 values are not extreme and are due wholly to exceptional con- 

 ditions of manufacture which would not obtain in commercial 

 practice. 



7. Standard maple syrup should weigh 11 pounds to the 

 gallon, should carry between 34 and 35$ of water, should give 

 a Baume reading of 35>4 to 36 at 6o G F., and should contain, 

 calculated to a moisture-free basis, a total (maple syrup) ash of 

 0.77%, an insoluble ash of 0.23$ and a malic acid value ol 



