L. J. HENDERSON, W. O. FENN, AND E. J. COHN 



395 



The importance of these results in bread making depends upon their 

 relation to a variety of other facts. First, it has long been known 

 that bread possesses a distinctly acid reaction. This is due to the 

 fact that beginning with an acid dough of hydrogen ion concentra- 

 tion 10-^ N or more, the process of fermentation produces an aug- 

 mentation of acidity. The observations of Jessen-Hansen in the 

 Carlsberg Laboratory confirm this fact by quantitative measurements 



O.OC> 0,l2 



O.JO OJt, 



0. 4-& dS-^ 0.6 



Fig. 4. 



and lead their author to the conclusion that about 10"^ N hydrogen 

 ion concentration is the most favorable for bread making. Obser- 

 vations of our own (except with a very weak flour) agree with those of 

 Jessen-Hansen. We have also made numerous measurements of the 

 hydrogen ion concentration of bread procured in the market, which 

 are entirely consistent with this view. 



Second, our studies reported in another paper of the rising 

 of dough and the carbonic acid production during fermentation 



