Various trade names are used to designate flours, as a 95 per cent patent, meaning that 95 per cent of the total flour is included in the patent; or an 85 per cent patent, when 85 per cent of all the flour is included in that particular patent. If all the flour streams were purified and blended, and only one grade of flour made, it would be called a 100 per cent patent. An 85 per cent patent is a higher grade flour than a 95 per cent patent.
[Illustration: FIG. 41.--SILK BOLTING CLOTH USED IN MANUFACTURE OF FLOUR, MAGNIFIED.]
156. Composition of Flour.--The composition of the different grades of flour made from the same wheat is given in the following table:[62]
COMPOSITION, ACIDITY, AND HEATS OF COMBUSTION OF FLOURS AND OTHER MILLED PRODUCTS OF WHEAT
=========================================================================== |WATER| PROTEIN | FAT| CARBO-| ASH| ACIDITY | HEAT OF MILLED PRODUCT | |(N × 5.7)| | HY- | | CALCUL- |COMBUSTION | | | | DRATES| |ATED AS | PER GRAM | | | | | |LACTIC |DETERMINED | | | | | | ACID | --------------------------------------------------------------------------- | % | % | % | % | % | % |Calories First patent flour |10.55| 11.08 |1.15| 76.85 |0.37| 0.08 | 4032 Second patent flour |10.49| 11.14 |1.20| 76.75 |0.42| 0.08 | 4006 Straight[A] or | | | | | | | standard patent |10.54| 11.99 |1.61| 75.36 |0.50| 0.09 | 4050 flour | | | | | | | First clear grade |10.13| 13.74 |2.20| 73.13 |0.80| 0.12 | 4097 flour | | | | | | | Second clear grade |10.08| 15.03 |3.77| 69.37 |1.75| 0.56 | 4267 flour | | | | | | | "Red dog" flour | 9.17| 18.98 |7.00| 61.37 |3.48| 0.59 | 4485 Shorts | 8.73| 14.87 |6.37| 65.47 |4.56| 0.14 | 4414 Bran | 9.99| 14.02 |4.39| 65.54 |6.06| 0.23 | 4198 Entire-wheat flour |10.81| 12.26 |2.24| 73.67 |1.02| 0.32 | 4032 Graham flour | 8.61| 12.65 |2.44| 74.58 |1.72| 0.18 | 4148 Wheat | 8.50| 12.65 |2.36| 74.69 |1.80| 0.18 | 4140 ===========================================================================
[Footnote A: Straight flour includes the first and second patents and first clear grade.]
In the table it will be noted that there is a gradual increase in protein content from first patent to "red dog," the largest amount being in the "red dog" flour. Although "red dog" contains the most protein, it is by far the poorest flour in bread-making qualities, and in the milling of wheat often it is not separated from the offals, but is sold as an animal food. It will also be seen that there is a gradual increase in the ash content from the highest to the lowest grades of flour, the increase being practically proportional to the grade,--the most ash being in the lowest grade. The grade to which a flour belongs can be determined more accurately from the ash content than from any other constituent. Patent grades of flour rarely contain more than 0.55 per cent of ash,--the better grades less than 0.5 per cent. The more completely the bran and offals are removed during the process of milling, the lower the per cent of ash. The ash content, however, cannot be taken as an absolute guide in all cases, as noticeable variations occur in the amount of mineral matter or ash in different wheats; starchy wheats that have reached full maturity often contain less than hard wheats grown upon rich soil where the growing season has been short, and from such wheats a soft, straight flour may have as low a per cent of ash as a hard first patent flour. When only straight or standard patent flour is manufactured by a mill, all of the flour is included which would otherwise be designated first and second patents and first clear.