288 POOD AND FOOD ADULTERANTS. 



SACCHARINE MATTER. 



The saccharine matter in beer consists principally of maltose and 

 dextrin, with probably a small proportion of dextrose. The greater 

 part of the entire extract is composed of these different carbohydrates. 

 The proportion of maltose to dextrin is of considerable importance in 

 judging of the quality of a beer. The dextrin contributes to the " full- 

 ness "(vollmiiudigkeit) of the taste, and a larger proportion of dextrin 

 to extract makes a beer of good ''body." The method of brewing is said 

 to have an important influence upon the relative proportions of maltose 

 and dextrin. The determination of the percentages of these sugars 

 is, therefore, quite an important one as showing the nature and quality 

 of the sample, though not of much utility in detecting adulterations. 

 The usual method is to estimate the maltose by Fehling's solution, and 

 the dextrin, if it is reported at all, is obtained by difference from the 

 total solids. So little is known of the saccharine bodies already existing 

 in the grain and of the products of the conversion of starch into sugars, 

 that their separate estimation is rather unsatisfactory.' The dextrin may 

 be determined directly by precipitating with alcohol, washing and weigh- 

 ing. The results are sufficiently accurate for commercial purposes, ac- 

 cording to J. West Knights, 2 who employed it upon worts. 



Graham estimates the maltose and dextrin in beer worts by the use 

 of Fehling's solution before and after inversion. 3 The cupric oxide re- 

 ducing power is determined gravimctrically, lOcc. arc measured out and 

 diluted to lOOcc. ; 20cc. of this solution are used to 30cc. Fehling's solu- 

 tion. The weight of Cut) obtained, multiplied by 0.7314 gives the 

 amount of maltese in the quantity of diluted liquid employed. The 

 maltose having been determined, lOcc. of the wort are mixed with 3cc. 

 of sulphuric acid, diluted to lOOcc. and inverted by heating to 100 

 C., for 3 to 4 hours in a flask furnished with a long tube. The vol- 

 ume of the solution is again made up to lOOcc., lOcc. carefully measured 

 or weighed, neutralized with sodium carbonate, and the reducing power 

 determined by heating with Fehliug's solution, in the same way as be- 

 fore. The percentage of dextrin is then calculated as follows : Mul- 

 tiply half the weight of CuO, obtained by the action of Fehling's solu- 

 tion on 2cc. of the original wort by 1.72, and subtract the product from 

 the CuO obtained from the inverted solution (= Ice. of the original). 

 The difference multiplied by 40.8 gives the grams of dextrin in lOOcc. 

 of the original wort. 



This method was applied to the samples analyzed with very unsatis- 

 factory results. In some cases the sum of the maltose and dextrin 

 determined in this way exceeded the amount of total extract, while in 

 other cases the per cent, of dextrin was a minus quantity. This 

 method was therefore abandoned. The results given were obtained by 



1 Recent work on this problem lias been published by O'Sullivau, Jour. Cheui. Soc., 

 Jan., 1886, p. 53. 



4 Allen's Organic Analysis 1, 274. 

 'Analyst?, 211. 



