WELCOME TO CALL US (+86) 18203311200 E-mail: admin@tehold-machine.com
Flour milling is a mechanical process that transforms cereal grains into fine particles suitable for human consumption. Wheat and maize represent the two most widely milled grains globally, each requiring specific equipment configurations due to differences in kernel structure and end-use applications. Wheat milling focuses on separating the endosperm from the bran and germ to produce white flour for bread, pasta, and pastries. Maize milling, in contrast, often aims to produce either whole meal for traditional porridges or degerminated flour for industrial baking.
For buyers evaluating wheat and maize flour milling machines, understanding the distinctions between these two processing lines is essential. While some equipment, such as cleaning towers and packaging units, can serve both grain types, the milling sections themselves are not interchangeable. Tehold International supplies dedicated lines for each grain, ensuring that the roller mill settings, sifter specifications, and aspiration systems match the physical properties of the input material.
The internal structure of wheat and maize dictates how milling machines must operate. A wheat kernel consists of three main parts: the bran, the germ, and the endosperm. The bran is a multi-layered protective coat that is tough and fibrous. The germ is the oil-rich reproductive portion of the kernel. The endosperm is the starchy interior that becomes white flour. In wheat milling, the goal is to scrape the endosperm from the bran in gradually smaller pieces without shattering the bran into fine powder.
A maize kernel has a similar structure but with a harder outer shell and a larger, more exposed germ. Maize milling often begins with a degermination step that removes the germ and part of the bran before the endosperm is reduced to grits or flour. This difference means that a wheat mill cannot process maize efficiently without significant modifications to the roller corrugations and the sifting circuits. Tehold International addresses this by offering separate, optimized lines for each grain rather than attempting to build universal machines that compromise on both.
A complete flour milling plant, whether for wheat or maize, includes several interconnected sections. Each section must be correctly sized to avoid bottlenecks that reduce overall throughput.
The process begins at the intake pit, where grain is dumped from trucks or bags. An elevator lifts the grain to a pre-cleaning machine that removes large impurities including straw, cob pieces, stones, and metal fragments. Pre-cleaning reduces wear on downstream equipment. The capacity of the intake system should match or slightly exceed the milling section’s rated throughput to avoid starving the mill during peak operation.
After pre-cleaning, the grain passes through a magnetic separator that captures ferrous metal particles. Metal contamination can damage roller mills, leading to costly repairs. Following magnetic separation, a de-stoner uses air flow and vibration to separate stones by density. Stones are heavier than grain and settle on a vibrating deck while the grain flows to the discharge. Effective de-stoning is particularly important for maize, which is often dried on open ground and may contain more stones than commercially dried wheat.
Conditioning is the addition of water to the grain to modify its mechanical properties. For wheat, tempering softens the bran and makes it more elastic, allowing the endosperm to be scraped off without excessive bran breakage. Optimal wheat tempering moisture varies by wheat hardness, typically between 15 and 16.5 percent after a resting period of 12 to 24 hours. Maize requires a shorter tempering time of 5 to 10 minutes at a moisture level around 14 to 16 percent. The conditioning system includes moisture meters to control water addition and tempering bins with specified retention times.
Maize mills producing degerminated flour for industrial snacks or breakfast cereals include a degermination step. A degerminator is a machine that uses a combination of attrition and centrifugal force to knock the germ off the endosperm. The germ is then separated using gravity tables or aspirators. Degermination reduces the oil content of the final flour, extending shelf life. For traditional maize meal where germ retention is acceptable, this step is omitted.
The roller mill is the central machine in any flour mill. A roller mill consists of two or more pairs of rolls that rotate toward each other at different speeds. The rolls have corrugations cut into their surfaces. For wheat break rolls, corrugations are deep and widely spaced to crack the kernel open. For reduction rolls, corrugations are fine and closely spaced to shear the endosperm into flour. Roll speed differentials create a shearing action that separates the endosperm from the bran.
For maize, break roll corrugations are typically deeper than those used for wheat because maize kernels are harder. Reduction rolls for maize grits are set with a wider gap to produce a coarser product than wheat flour. When a mill owner intends to process both grains at different times, the roller mills must be re-corrugated between changeovers, which is time-consuming and impractical for most operations. Tehold International therefore recommends separate lines.
After each roller mill pass, the ground material is pneumatically conveyed to a plansifter. A plansifter is a large box containing multiple layers of sieves stacked vertically. The sieves are arranged so that coarse material exits at one port, middlings at another, and flour at a third. Coarse material returns to the next set of break rolls, while middlings go to reduction rolls.
Purifiers are used in wheat milling to separate bran particles from endosperm middlings. A purifier uses a gentle air current to lift bran fragments while allowing heavier endosperm particles to fall through vibrating sieves. Purifiers are less common in maize milling because maize bran behaves differently. The presence or absence of purifiers is one of the visible differences between a wheat mill and a maize mill.
The commercial success of a flour mill depends heavily on the extraction rate: the percentage of incoming grain that becomes sellable flour. For wheat flour, a standard white flour extraction rate ranges between 72 and 78 percent. The remaining 22 to 28 percent consists of bran, germ, and screenings. Wheat bran and germ have value as animal feed but generate lower revenue per kilogram than flour.
Maize milling extraction rates vary by product type. Traditional sifted maize meal, which includes some bran, has an extraction rate of 80 to 85 percent. Degerminated maize flour, processed for industrial uses, has an extraction rate of 65 to 75 percent. The lower extraction rate for degerminated flour is acceptable when the germ is sold separately to oil extraction facilities.
Flour milling is energy-intensive. The specific power consumption of a wheat mill ranges from 40 to 60 kilowatt-hours per metric ton of grain processed. For a plant processing 50 metric tons per day, this translates to a continuous power demand of approximately 100 to 125 kilowatts, assuming 20 hours of operation per day.
Maize milling typically requires more energy per ton due to the harder kernel structure. Specific power consumption for a degerminated maize mill falls between 50 and 70 kilowatt-hours per metric ton. For a 30-ton-per-day maize mill, continuous power demand reaches 75 to 105 kilowatts.
Most medium and large mills in Kenya operate on three-phase electrical systems at 415 volts, 50 hertz. The main motor for a 2-ton-per-hour roller mill draws between 60 and 90 amperes under full load. When all auxiliary equipment—elevators, aspirators, sifters, and packaging machines—are considered, the total amperage for a 2-ton-per-hour line ranges from 120 to 180 amperes. Backup power through diesel generators is common in areas with unstable grid supply.
Tehold International provides complete milling solutions tailored to the grain type and target output quality. The company’s product line includes modular units that allow millers to expand capacity over time.
For entry-level operations, Tehold offers compact hammer mills that can process either wheat or maize but not both without screen changes. These units are suitable for village-level service milling where customers bring their own grain. A 7.5-kilowatt single-phase hammer mill processes 200 to 300 kilograms per hour. A 15-kilowatt three-phase unit processes 400 to 600 kilograms per hour. Single-pass mills produce whole meal flour with no separation of bran or germ.
For market centers requiring sifted flour, Tehold supplies two-stand and four-stand roller mill lines. A two-stand line includes one set of break rolls and one set of reduction rolls, plus a plansifter and a small aspirator. This configuration processes 500 kilograms per hour of wheat or 400 kilograms per hour of maize, producing two flour streams: a premium sifted flour and a lower-grade byproduct.
A four-stand line includes two break passes and two reduction passes. This system increases the extraction rate of sifted flour by approximately 5 percentage points compared to a two-stand line. The four-stand configuration processes 1,000 to 1,500 kilograms per hour of wheat or 800 to 1,200 kilograms per hour of maize.
For investors targeting supermarket distribution, Tehold International designs plants with six or more roller mill stands, multiple plansifters, and purifiers for wheat lines. A six-stand wheat plant processes 3 to 5 tons per hour with a flour extraction rate of 74 to 76 percent at 0.6 to 0.8 percent ash content. The same plant configured for maize would have a different roll corrugation and would produce either grits or fine flour.
Tehold’s industrial plants include automated controls that monitor roll gap, moisture addition, and sifter performance. These systems reduce labor requirements. A 50-ton-per-day wheat mill requires a team of four to six operators per shift, while a similarly sized maize mill requires three to four operators due to the simpler sifting circuit.
The cost of a wheat or maize milling machine varies with capacity, automation level, and material quality. Tehold International provides transparent cost breakdowns for each project. For a medium-scale line with 1-ton-per-hour capacity for wheat or 800-kilogram-per-hour capacity for maize, the equipment cost falls between USD 45,000 and USD 75,000 depending on the number of roller stands and the inclusion of automated moisture control.
For an industrial 5-ton-per-hour wheat mill with full cleaning, tempering, six roller stands, four plansifters, and a packaging line, the equipment cost ranges from USD 250,000 to USD 450,000. The same capacity for degerminated maize meal would be USD 30,000 to USD 50,000 less due to the absence of purifiers and the simpler sifting configuration.
Buyers should add installation costs, which typically represent 10 to 15 percent of equipment value for local assembly. International shipping from Tehold’s manufacturing partners to Mombasa port adds 8 to 12 percent depending on container volume. Import duties and value-added tax in Kenya vary by equipment classification but generally add 15 to 25 percent to the landed cost.
Ongoing costs determine long-term viability more than the initial equipment purchase. For a 1-ton-per-hour wheat mill operating 250 days per year, annual grain consumption reaches 2,000 metric tons at 8 hours per day or 4,000 metric tons at 16 hours per day. At a wheat price of KES 45 per kilogram, annual grain costs alone range from KES 90 million for single-shift operation to KES 180 million for double-shift operation.
Power costs for the same mill, assuming 50 kilowatt-hours per ton and a commercial electricity tariff of KES 20 per kilowatt-hour, amount to KES 1,000 per ton of wheat processed. Over 4,000 tons, power costs reach KES 4 million annually. Labor costs for a four-person shift at KES 30,000 per person per month total KES 1.44 million per year for single-shift operation or KES 2.88 million for double-shift.
Flour revenue depends on extraction rate and selling price. At a 75 percent extraction rate, 1 ton of wheat produces 750 kilograms of flour. At a wholesale flour price of KES 60 per kilogram, revenue per ton is KES 45,000. The remaining 250 kilograms of bran sells at KES 15 per kilogram for an additional KES 3,750. Total revenue per ton is KES 48,750. After subtracting grain cost of KES 45,000, the gross margin is KES 3,750 per ton before power, labor, and overhead. This margin works for high-volume operations but requires strict cost control.
Operating a flour mill in Kenya requires compliance with several legal frameworks. The Kenya Bureau of Standards sets specifications for wheat and maize flour under KS EAS 2 for wheat flour and KS EAS 774 for maize flour. These standards specify maximum moisture content, ash content, and aflatoxin levels. Mills must test their flour regularly to demonstrate compliance.
Food hygiene regulations require that milling equipment be constructed from materials that do not contaminate the product. Stainless steel is mandatory for surfaces that contact the flour in modern facilities. Tehold International specifies food-grade stainless steel for all product-contact parts in their milling lines.
For wheat flour, enrichment with iron and folic acid is required under Kenyan law for all milled flour intended for public consumption. The enrichment levels are specified by the Ministry of Health. Mills must install micro-dosing equipment that adds premix vitamins and minerals to the flour stream at a controlled rate. Tehold can include enrichment feeders as part of a complete line.
Preventive maintenance extends equipment life and reduces unplanned downtime. For roller mills, the most critical maintenance task is roll re-corrugation. Wheat break rolls require re-corrugation after processing 4,000 to 6,000 metric tons. Wheat reduction rolls, which operate at a finer gap, require re-corrugation after 8,000 to 10,000 metric tons. Maize rolls require re-corrugation after 3,000 to 5,000 metric tons due to the harder kernel.
Plansifter sieves have a shorter service life. Nylon sieve frames for wheat milling last approximately 800 to 1,200 operating hours before they show wear that affects sifting efficiency. Polyurethane frames last 2,000 to 3,000 hours. Mills should stock at least one complete set of spare sieves and a set of cleaning brushes.
Tehold International supplies a recommended spare parts list with each milling line. The list includes bearings, belts, sieve frames, and a set of roll corrugation tools. Storing these parts on-site reduces the risk of extended downtime when a component fails.
The choice between a wheat mill and a maize mill depends on local consumption patterns. In Kenya, maize meal is the primary staple, consumed by over 90 percent of households on a daily basis. Wheat flour is a secondary staple, used for bread, chapati, and cakes. Per capita wheat consumption in Kenya is approximately 25 kilograms annually, compared to 90 kilograms for maize.
A wheat mill in Kenya must compete with a small number of very large mills that dominate the bread flour market. New entrants typically focus on specialized wheat products such as whole wheat flour or flour for local bread varieties where import substitutes exist. A maize mill serves a larger total market but faces competition from both large industrial mills and thousands of small posho mills. The optimal position for a medium-sized investor is often a maize mill producing sifted meal for urban retail, where customers value consistent quality over the lowest price.
Wheat and maize flour milling machines differ in design due to the distinct structures and intended uses of the two grains. Wheat milling requires more complex sifting and purifying to separate bran from endosperm, achieving extraction rates around 75 percent. Maize milling achieves higher extraction rates of 80 to 85 percent for traditional meal or lower rates for degerminated industrial flour.
Tehold International supplies dedicated milling lines for both grains, with capacities ranging from 200 kilograms per hour for small-scale operations to 5,000 kilograms per hour for industrial plants. Each line includes grain cleaning, tempering, roller milling, sifting, and packaging equipment sized to work together without bottlenecks. For buyers in Kenya, the decision between wheat and maize milling should be guided by local consumption volumes, competition levels, and access to grain supply. A professional evaluation of these factors, combined with accurate equipment specifications from a supplier like Tehold, leads to a milling investment that performs as expected over a decade or more of operation.
