Wheat Flour Milling, Second Edition
Pages 291-327
DOI: https://doi.org/10.1094/1891127403.009
ISBN: 1-891127-40-3
Abstract
The flour-handling system can be a very simple on-stream packing operation; a simple load-out facility into bulk trucks and rail cars, with only a surge storage bin to hold the flour stream from the mill between switches; or an extensive storage and flour-blending system to ensure uniform quality of the flour shipments and to treat the flour for special products. The flour-blending department often has facilities for such treatments of the flour as infestation control, enrichment and additives, flour stabilization, flour drying, fine grinding, and air classification. The system can employ a process computer for fully automatic operation of the flour blending, final packing, invoicing, and loading for shipment to the customer.
The on-stream system requires that all the flour treatment and final rebolt sifting be done in the mill. Special feeders (Fig. 9-1) are used to feed very small amounts of ingredients and enrichments to the flour stream, which is agitated at high speed in a nonmetal agitator (Fig. 9-2). There is no room for mistakes, and coordination with transportation is critical. Uniform wheat mixes and online quality control also are important. Variations in flour quality that may occur from the wheat mix or the milling process are passed on to the customer or are unloaded and rehandled at extra expense. The advantages of the system are low capital costs and low operational expenses.
Most modern mills have more extensive storage and flour-blending systems. They provide facilities for storing and blending flour to ensure uniform flour quality. Flour quality is analyzed as the flour goes into the storage bins, and blending produces a flour of known quality characteristics before shipment. Some mills manufacture basic flour grades for storage and blend from these bins in the proper percentages to meet the flour specifications of the customer. This provides the maximum flexibility for producing flour grades without mill adjustment, where length of run and other factors could make it impossible to change the milling system for a short run of a given grade of flour. It also improves milling efficiency by optimizing the mill adjustments over a longer period.
Many mills also provide sufficient flour storage capacity to pack or load on the day shift only in order to save labor costs and better control the operation while the laboratory and management staff is present. This operation can be expanded to include special treatment of the flour for certain customers, such as flour drying, air classification, stabilization of enzymatic action, and addition of ingredients. An extensive flour-handling system adds to the cost of the operation, but it gives millers more control of the final flour quality and, thus, provides better service to the mill customers.
