DEVELOPMENT OF ACIDS DURING FERMENTATION.
A comparison of the amounts of volatile and fixed acids in the worts and in the finished beers shows that normally there is no appreciable development of volatile acid during fermentation and only a slight increase in the fixed acid. This increase in fixed acid averages in the case of the beers 0.049 per cent, while in the case of the ales the increase averages 0.103 per cent.
DECREASE IN PROTEIN, ASH, AND PHOSPHORIC ACID.
A general study of the preceding tables will show that there is an appreciable loss of protein, ash, and phosphoric acid during the fermentation. Table VI has been prepared to show the average loss during fermentation of the various classes of worts with respect to their protein, ash, and phosphoric acid contents.
[ Table VI.]—Average loss during fermentation.
![[ Table VI.]](#1508760487148995903_table6.png.id-5458081185437861227.wrap-0.html.html){kind=link}
| Kind of wort. | Protein. | Ash. | Phosphoric acid. |
| Grams per 100 cc. | Grams per 100 cc. | Grams per 100 cc. | |
| Beer worts (all-malt) | 0.209 | 0.017 | 0.015 |
| Beer worts (malt and rice) | .210 | .045 | .014 |
| Beer worts (malt and corn) | .168 | .014 | .013 |
| Porter worts | .213 | .031 | .017 |
| Ale worts | .275 | .029 | .019 |
The results given in Table VI show a great similarity in the changes in all of the products, as there is about the same amount of loss of protein, ash, and phosphoric acid in the beer, ale, and porter worts. There does not appear to be any appreciable loss, however, of either protein or phosphoric acid during the storage or aging period as is shown by the few samples which we have analyzed after storage. This is practically in agreement with the experiment of Bertschinger, [1] whose results show only a very slight increase in alcohol and loss of sugar during the storage period.
[1] Z. angew. Chem. (1890), p. 670.