22 



method of titration after driving off the volatile acids by steam distillation. Volatile 

 acids were determined by the indirect method of Windisch and by the proposed new 

 direct method of distilling by steam. In the Windisch methods the titrations were 

 made using litmus paper as an indicator and in the method of Sellier, as in the pro- 

 posed new methods, phenol phthalein was used. 



Comparison ofjrtiethodsfor the determination of total, fixed, and volatile acids in wines. 

 [Results expressed as cc tenth-normal acid in 100 cc of sample.] 





Kind of wine. 



Total acids. 



Method 

 of Cali- 

 fornia 

 Wine 

 Associa- 

 tion. 



Meth- 

 od of 

 Win- 

 disch. 



Pro- 

 posed 

 new 

 meth- 

 od. 



Calcu- 

 lated 

 from 

 fixed 

 and vola- 

 tile acids. 



Fixed acids. 



Meth- 

 od of 



Win- 

 disch. 



Meth- 

 od of 

 Sellier. 



Proposed new 

 method. 



Using 

 litmus. 



j Using 

 phenol- 

 phthal- 

 ein. 



Calcu- 

 lated from 

 total and 

 volatile 

 acids. 



Angelica. 

 Claret.... 



Port 



Riesling.. 

 Sherry... 

 Zinfandel 

 Sauterne. 

 Bordeaux 

 Sauterne. 



Port 



Sherrv... 

 Claret.... 



Port 



Sherry... 

 Claret..^ 



4.30 

 7.70 

 5.20 

 6.00 

 4.00 



a 70 



C.70 

 7.10 

 7.70 

 8.90 

 5.50 

 5.60 

 6.80 

 5.90 

 8.50 



4.16 

 7.52 

 5.60 

 6.36 

 4.50 

 7.92 

 7.58 

 8.16 

 8.20 

 8.44 

 5.80 

 10.60 

 6.30 

 6.40 

 8.40 



5.80 

 9.60 

 7.20 

 7.45 

 5.35 

 9.70 

 8.55 

 9.15 

 8.90 

 9.55 

 6.60 

 11.90 

 7.10 

 7.20 

 9.50 



5.80 

 9.55 

 7.15 

 7.50 

 5.35 

 9.75 

 8.60 

 9.20 



11.90 

 7.10 

 7.25 

 9.60 



3.32 

 6.80 

 4.36 

 4.80 

 2.96 

 5.64 

 5.48 

 6.00 

 6.00 

 3.60 

 7.40 

 4.40 

 3.60 

 6.20 

 0.14 



4.90 

 8.00 

 5.90 

 6.15 

 3.95 

 6.75 

 6.40 

 7.30 

 7.75 

 4.80 

 9.60 

 5.50 

 5.70 

 7.90 

 8.20 



3.40 

 7.00 

 5.00 

 5.20 

 3.00 

 5.50 

 5.00 

 6.00 

 6.50 

 3.70 

 8.20 

 4.50 

 4.00 

 6.40 

 6.55 



5.00 

 8.00 

 6.00 

 6.10 

 3.90 

 6.75 

 6.50 

 6.95 

 7.30 

 4.40 

 9.20 

 5.20 

 4.80 

 7.70 

 8.10 



5.00 

 8.05 

 6.05 

 6.05 

 3.90 

 6.70 

 6.45 

 6.90 

 7.25 

 4.40 

 9.20 

 5.20 

 4.75 

 7.60 

 8.05 



No. 



Kind of wine. 



Volatile acids. 



Ratio of volatile to 

 fixed acids. 



Method of 

 Windisch. 



Proposed new method. 



Using 

 litmus. 



Using 



phenol- 



phthalein. 



Calculated 



from total 



and fixed 



acids. 



According According 



to method to proposed 



of new 



Windisch. method. 



1 Angelica.. 



2 Claret 



3 Port 



4 Riesling. . 



5 Sherry.... 

 a 6 Zinfandel. 



67 Sauterne.. 



68 Bordeaux. 

 9 Sauterne.. 



10 Port 



11 Sherry.... 

 12 Claret... 

 <*13 Port 



14 Sherrv 



15 Claret... 



0.84 



.72 



.24 



.56 



.54 



.94 



2.68 



2.20 



2.44 



2.20 



3.20 



1.90 



2.80 



2.20 



1.78 



0.70 

 1.40 

 .95 

 1.15 

 1.20 

 1.30 

 2.10 

 1.70 

 2.00 

 1.90 

 2.40 

 1.60 

 2.00 

 1.60 

 1.40 



0.85 



.55 



.15 



.40 



.45 



.85 



2.70 



2.00 



2.30 



2.20 



2.70 



1.90 



2.45 



1.90 



1.65 



0.80 

 1.60 

 1.20 

 1.35 

 1.45 

 1.80 

 2.65 

 1.95 

 2.25 

 2.20 

 2.70 

 1.90 

 2.40 

 1.80 

 1.60 



:3.95 

 :3.95 

 : 3. 51 

 :3.07 

 :1.92 

 : 2.90 

 :2.04 

 :2.73 

 :2.46 

 :1.64 

 :2.31 

 :2.32 

 : 1.28 

 :2.82 

 3.44 



6.25 

 5.16 

 5.21 

 4.35 

 2. CM 

 3.69 

 2.40 

 3. 47 

 3.17 

 2.00 

 3.41 

 2.74 

 1.96 

 4.05 

 5.06 



o First six wines furnished by the California Wine Association, 1908. 

 6 7 and 8 obtained from local dealers, 1908, St. Paul, Minn. 

 c 9 to 12, inclusive, from a Rochester, X. V., wine company, 1908. 

 <* 13 to 15, inclusive, from a Norfolk, Va., wine company, 1908. 



The results obtained by the California Wine Association method were not satis- 

 factory, the end-point of the titrations being, in most instances, very uncertain. 

 In the angelicas, ports, and sherrys especially, much difficulty was experienced 



