A STUDY OF THE INFLUENCE OF INOCULATION UPON 
THE FERMENTATION OF SAUERKRAUT 1 
By 0. R. Brunkow, W. H. Peterson, and E. B. Fred, of the Departments of 
Agricultural Chemistry and Agricultural Bacteriology , University of Wisconsin 
INTRODUCTION 
The older literature on the subject 
of sauerkraut fermentation is concerned 
chiefly with a study of the micro¬ 
organisms found in kraut without 
devoting much attention to the kinds 
and amounts of fermentation products. 
A review of this literature has been 
given in a previous publication 2 and 
need not be repeated here. In papers 3 
published from these laboratories the 
chief fermentation products contained 
in sauerkraut were found to be: Lactic 
acid, 0.93 to 1.65 per cent; acetic acid, 
0.22 to 0.47 per cent; ethyl alcohol, 
0.14 to 0.84 per cent. The variation 
in composition depends upon many 
factors such as the age of the kraut, 
the type of organisms present, and the 
temperature and completeness of the 
fermentation. 
The success which has attended the 
use of selected cultures of bacteria in 
the butter and chebse industry and in 
the growing of nitrogen-assimilating 
legumes suggests the use of similar 
methods in the kraut industry. 
Some data were submitted in a pre¬ 
vious paper 4 to show that the quality 
of the kraut and the quantity of the 
fermentation products could be in¬ 
fluenced by the use of selected cultures 
of lactic acid bacteria. This work has 
been continued on a larger scale for 
the past two years and the results 
obtained are presented in this paper. 
EXPERIMENTAL DATA 
It was planned to study the chief 
bacteriological and chemical changes 
which take place at different times 
during the fermentation in both an 
uninoculated and inoculated kraut. 
The organism selected for the inocula¬ 
tion of the kraut was a strain of 
Streptococcus lactis originally isolated 
from milk. The use of this culture had 
consistently given a better quality of 
kraut than any of the other organisms 
tried and also better than the uninocu¬ 
lated control. 
The shape of the organism, the forma¬ 
tion of a smooth firm curd in milk, and 
its failure to ferment xylose increased 
the possibility of its detection in kraut. 
Its chemical products are also dis¬ 
tinctive. It has been shown that this 
strain of Streptococcus lactis ferments the 
common sugars with the formation of 
active lactic acid and the production of 
little or no carbon dioxide, alcohol, or 
acetic acid. 
Although some of the results pre¬ 
viously reported were obtained on 
kraut made under factory conditions, 
much of it was made in large percola¬ 
tors of 3-liter or 4-liter capacity or 
small 2-gallon stone jars. In order 
to simulate factory conditions more 
closely, two large cypress vats about 5 
feet high and 2 feel in diameter were 
constructed. A small well was built on 
the inside of each vat. This was made 
by attaching a V-shaped trough, made 
from two 3-inch boards, to the inside of 
the vat, so that the brine could rise 
freely in it. Samples of brine could be 
taken from these wells at any time 
during the fermentation period with¬ 
out distrubing the contents of the vat. 
It was found that as the fermentation 
proceeded the acidity of the brine in 
the wells was not the same as that of 
the brine in the vat, so a hole was 
bored through the side of the vat about 
2 feet from the bottom and samples of 
the brine were drawn from here through 
a glass tube inserted through a rubber 
stopper. In order to obtain the tem¬ 
perature of the brine, a theremometer 
was suspended deep in the well. 
The vats were filled with 250 pounds 
of cut cabbage at a kraut factory near 
Madison, Wis. The cabbage used for 
filling the vats was the same as that 
used in the factory and was prepared 
1 Received for publication July 26, 1924: issued July, 1925. Published with the permission of the Direc¬ 
tor of the Wisconsin Agricultural Experiment Station. 
2 Brunkow, O. R., Peterson, W. H., and Fred, E. B. the influence of certain factors upon the 
chemical composition of sauerkraut. Jour. Amer. Chem. Soc. 43: 2244-2255, illus. 1921. 
3 Peterson, W. EL, and Fred, E. B. an abnormal fermentation of sauerkraut. Centbl. Bakt. 
(II) 58: 199-204, illus. 1923. 
4 Fred, E. B., and Peterson, W.H. factors determining quality in kraut. Canning Age 1924 
(Illus. Conv. Digest): 161-165, illus. 1924. 
Journal of Agricultural Research 
Washington, D. C. 
( 955 ) 
Vol. XXX, No. 10 
May 15, 1925 
Key No. Wis—30 
