Color.--The highest grades of flour are white in color, or of a
slight creamy tinge. Dark-colored, slaty, and gray flours are of
inferior quality, indicating a poor grade of wheat, poor milling, or a
poor quality of gluten. Flours, after being on the market for a time,
bleach a little and improve to a slight degree in color. Color is one of
the characteristics by which the commercial value of flour is
determined; the whiter the flour, the better the grade, provided other
properties are equal[9]. The color, however, should be a pure or cream
white. Some flours have what is called a dead white color, and, while
not objectionable as far as color is concerned, they are not as valuable
for bread-making and general commercial purposes. One of the principal
trade requirements of a flour is that it possess a certain degree of
whiteness and none of the objectionable shades mentioned.

To determine the color of a flour, it is compared with a standard. If it
is a winter wheat flour, one of the best high-grade winter patents to be
found on the market is selected, and the sample in question is compared
with this; if it is a spring wheat patent flour, one of the best spring
wheat patent grades is taken as the standard. In making the comparison,
the flours should be placed side by side on a glass plate and smoothed
with the flour trier, the comparison being made preferably by a north
window. Much experience and practice are necessary in order to determine
with accuracy the color value of a flour.

162. Granulation.--The best patent grades of flour contain an
appreciable amount of granular middlings, which have a characteristic
"feel" similar to fine, sharp sand. A flour which has no granular
feeling is not usually considered of the highest grade, but is generally
a soft wheat flour of poor gluten. However, a flour should not be too
coarsely granulated. The percentage amounts of the different grades of
stock in a flour can be approximately determined by means of sieves and
different sized bolting cloths. To test a flour, ten grams are placed in
a sieve containing a No. 10 bolting cloth; with a camel's-hair brush and
proper manipulation, the flour is sieved, and that which passes through
is weighed. The percentage amount remaining on the No. 10 cloth is
coarser middlings. Nearly all high-grade flours leave no residue on the
No. 10 cloth. The sifted flour from the No. 10 cloth is also passed
through Nos. 11, 12, 13, and 14 cloths[63]. In