this purpose it would be necessary to collect a series of
samples made from the various raw materials ordinarily used and make a
study of the effect of these raw materials upon the composition of the
finished product.

The investigation seemed desirable for the reason that practically all
of the existing data related to foreign beers, in the preparation of
which a type of malt was used entirely different from that ordinarily
used in the production of American beers. Furthermore, very few of the
existing data relating either to foreign or domestic beers were based
upon samples concerning which exact information was available in regard
to the raw materials used in the wort.

METHOD OF UNDERTAKING THE INVESTIGATION.

It was felt that it would be wholly unsatisfactory to make this
investigation by means of laboratory brewings on a small scale, as the
results thus obtained would not show the true conditions, because it is
not possible in the laboratory to duplicate exactly the mashing or
fermenting processes actually used in a commercial way. It was decided,
therefore, to attempt, with the cooperation of several breweries, to
make this study under the exact conditions prevailing in commercial
plants. Access was secured to several breweries making different types
of products from various kinds of raw materials, under such conditions
that it was possible to obtain a complete history of the beer through
its various stages to the finished product. One of the writers (Riley)
watched the method of manufacture during its whole process and obtained
samples of the product at the various stages of manufacture. Thus, it
was possible to procure finished samples with practically the same
degree of certainty, as regards knowledge of composition and history, as
would have been the case had they been prepared in the laboratory.

In three different breweries manufacturing a wide range of products
samples of the wort and beer were obtained in this manner, the entire
process of manufacture being studied in detail. A record showing the
kind and amount of raw materials placed in the mash and in the cooker
was made of the samples collected from these three breweries. A record
also was kept of the time and temperature of each operation until the
mash was ready to run into the kettle. The filtering and sparging[1] of
the mash, the time of boiling in the kettle, the amount of hops added
and the point at which they were added, and the break[2] o