Mustard-Seed comes from Russia, Germany, England and Holland, and to
some extent from California. There are two chief divisions, yellow and
brown. The brown seed comes largely from Italy and is known as Bari. The
term Trieste is frequently applied to all brown Mustard-Seeds.
Mustard-Seed contains two oils, known as Essential and Fatty. The
Essential Oil is soluble in water. In flavor and odor it closely
resembles horseradish. The Fatty Oil is mild and tasteless, insoluble in
water, and is sometimes used in place of olive oil.
In manufacturing Mustard-Flour the seed is warmed, subjected to
hydraulic pressure, which releases from fifteen to twenty-five per cent
of the fatty oil. The residue is called Mustard-Cake. It is ground and
bolted on fine sieves, separating the Mustard bran or hulls from the
interior, making ground mustard or flour. Brown seed contains a larger
percentage of the essential oil, and, therefore, makes a hotter or
stronger flour than the yellow variety, and must be blended with flour
from yellow seed.