Flour Milling in East Africa
March 01, 1999
by Teresa Acklin
High production costs, poor flour quality and little product diversification hinder East African flour mills.
This article is based on a presentation by Mario Cinquetti, sales director for Braibanti Golfetto S.p.A., Padova, Italy, at the Association of Operative Millers' Middle East/East Africa District 16 conference in Nairobi, Kenya, last year.
In 1904, Lord Delamare installed the first flour mill with rollermills in Nairobi, East Africa. Since then, at least four generations of millers have faced the demand of markets that have been in continual expansion as the population has increased and economic conditions have improved.
However, milling capacity in East Africa today exceeds demand, and market requirements are becoming more demanding under the influence of world consumer trends. To compete, East African flour mills must begin to reduce production costs, improve flour quality and increase product diversification.
A competitive flour price is essential to success. The primary objective of management should be to lower production costs.
One of the disadvantages of African mills compared with European mills is lower productivity. Compared with an average 15 tonnes of wheat milled per employee in Europe, including administrative staff and management, only three tonnes are produced per employee in Africa. So, a 300-tonne flour mill in Africa must pay more than 100 salaries against 20 in Europe. Unfortunately, the cheap cost of labor in Africa is not sufficient to compensate for this disadvantage. Labor costs for African mills that produce flours of high and consistent quality become even more complex because of the difficulty in obtaining professional millers and expert laboratory analysts at a reasonable cost.
African millers also face greater costs of wheat storage and preservation from storage in sacks instead of bulk. A modern silo equipped with suitable precleaning plants and temperature control, ventilation and disinfestation systems can lower costs without excessive investment. An 8,000- to 10,000-tonne-capacity metal silo costs about U.S.$50 per tonne, including mechanization and erection.
East African mills also are at a disadvantage because of depreciation, which can be as much as 20% of the production cost, excluding the wheat. When purchasing machinery, investment should be minimized and rigid. Clear guarantees concerning production, yield and machinery reliability must be demanded.
CONCRETE DOES NOT PRODUCE FLOUR.
Do not become enchanted by grandiose projects with five- or six-story buildings in order to eliminate three or four pneumatic conveying lines. Buildings of two or three stories are sufficient. In addition to the lower cost, it also is easier to control the plant.
The ideal volumetric parameter for a 300-tonne flour mill is approximately 25 cubic meters per tonne of wheat ground during 24 hours. This figure includes the daily wheat silos, a 36-hour wheat tempering silo and 48-hour production capacity flour silos.
Flour silos can reduce production costs. With 24-hour production capacity silos, it is possible to work two shifts without eliminating personnel. With 48-hour flour silos, the mill can be run with only millers, even during the weekend. A flour silo equipped with high efficiency sacking lines enables direct loading of lorries, avoiding costly storage of sacked flour in a warehouse.
Another important advantage of a large flour silo is the possibility of mixing various qualities of basic flour so that the desired type can be composed at the time of delivery. In this way, it is possible to mill soft wheat separately from semi-hard types to increase the flour yield.
Along with progressive development in the bakery, biscuit and pasta-making industries, it also is possible to maximize bulk flour delivery and reduce the quantity of sacked delivery. In Italy, almost half of flour production is distributed in bulk.
Another great handicap for the African mill is the modest return obtained from the local sale of byproducts. This is estimated at some 10% of the commercial price of the flour, as opposed to some 40% in European mills.
While awaiting the expected development of the African feed industry which is strictly conditioned by the extremely limited per capita consumption of meat a suitable pelleting plant needs to be in place to reduce transportation costs in order to be in a position to export overseas.
IMPROVE FLOUR QUALITY.
Flour quality is correlated to use. Bread flours must have a good protein content and be sufficiently fine for high water absorption. Conversely, flours for domestic use do not have to be as fine and may have a lower protein content to compensate for the high cost of packing.
Color is important for both types of flour. In Europe, the tendency is to produce flours with a low ash content. In East Africa, on the other hand, color is less important than high flour yield. In Africa, it is normal to find mills with 80% flour yield with 0.70% to 0.72% of ash content in dry matter. This is because many mills are equipped with obsolete machinery and need to grind hard and soft wheat mixed together because of the lack of flour silos.
Various qualities of wheat require different conditioning times 30 to 36 hours for hard types and 20 to 24 hours for soft types. Moreover, the opposite degree of hardness between soft and hard kernels imposes a different regulation of the rollermill gap.
Considering the keen market competition over quality, it is questionable whether these mills will survive unless they are radically upgraded. They must be either restructured with modern machinery utilizing flexible diagrams or replaced with new plants that can double or triple the present daily capacity. In either case, mills must be able to guarantee higher flour yields and lower ash content as well as minimizing costs.
New mills with a specific grinding length of 10 millimeters per 100 kilograms of wheat ground in 24 hours work the vitreous wheat better and produce fine flours with high yields. Net sifting surfaces should measure not less than 0.065 square meters per 100 kilograms of wheat ground in 24 hours in order to efficiently sift the intermediate and final products of soft wheats. This is especially true in tropical countries where the air humidity reaches high levels.
To produce lower ash content flours, mills should be equipped with semolina purifiers for cleaning the semolina prior to final refining. Three machines are adequate for a 300-tonne mill.
To obtain finer bread flours (132 micron), pin mills should be employed on the C1 and C2 refining passages. These machines, with a rotor of 900 millimeters diameter and three rows of pins, pulverize the semolina at a peripheral speed of 100 meters per second.
Modern variable feed speed rollermills obtain better grinding results with a high degree of automation. For high productivity mills designed to produce very fine and high absorption flour, which is ideal for loaf bread, variable speed rollermills should be used for the reduction passages with roll diameter of 300 millimeters.
The advantages of these modern machines include:
Minimum roll table flexion for a complete exploitation of the grinding length;
More adaptability to overloads and minimum effect of continuous load variations caused by the feeding roll fluting;
Better heat dispersion because of the greater grinding surface;
Notable damage of the hard wheat starch 38 to 40 Farrel units instead of the 30 to 32 with 250 millimeter diameter rolls which aids in water absorption in bread making;
Much finer flours 80% passes through 100 micron cover; and
66% water absorption when grinding hard wheat with 10 millimeter grinding length.
Keep in mind the importance of the chemical analysis laboratory in the managing of a modern flour mill.
Lowering costs and improving product quality is not sufficient without market diversification.
East African mills today produce only three or four types of flour, whereas an Italian mill produces at least 20. The Lario 400-tonne mill at Como in the Milan hinterland produces more than 60 different types of flour, which are delivered with an analysis certificate guarantee.
In Italy, three types of bread flour are manufactured: high protein content (13%); medium protein content (12%); and minimum protein content (10.5%). These three types become six, considering that the market requires flour having a low ash content (0.50%), denominated “double O,” corresponding to cake flour, and flour having a medium ash content (0.56%), denominated “O,” specific for commercial bread. In any case, the percentage of ash content is referred to dry matter, and the “W” index of Chopin's alveograph is declared.
For sophisticated marketing reasons, some mills produce flours for particular types of bread French baguettes, puffed rolls, Italian ciabatta, loaf, homemade, sponge bread for hamburgers, Arabian unleavened bread, wholemeal, etc. Flours also are produced for pizzas, brioches, baby foods, biscuit bread, breadsticks and industrial confectionery.
Flours with low protein content (minus 10%) are produced for hard and soft biscuits and can be of various qualities for different kinds of biscuits Mary, petit beurre, rich tea, tender biscuits, cookies, shortcake and crackers.
There are at least three varieties of flour for domestic use in Italy. These are used mainly for home cakes and fresh pasta and for flouring meat, fish and vegetables to be fried. These flours are packed in paper bags of 500 or 1,000 grams.
Finally, there is semolina for soups or fresh pasta and wholemeal flours which, by law in Italy, must contain sterilized bran.