Skip to main content
Maize Starch & Flour Processing Plants
Cereals, Tubers & Sugar Processing

Maize Starch & Flour Processing Plants

A maize processing plant makes either starch by wet milling or flour, meal and grits by dry milling. The two routes need different equipment, water and by-product handling, so the product comes first.

Request a QuoteWhatsApp

Product Categories

Talk to Kadali Africa Ventures

Send your raw material, product and capacity for a technical proposal.

Contact Kadali

Related Products

Large stainless-steel vessel with a tall vapour column, insulated pipework and further vessels in a process hall with yellow walls

Maize Starch & Flour Processing Plants

Both routes begin with clean, sound maize, but after intake they have little in common. Dry milling cracks, degerms, grinds and sifts the dry kernel into grits, meal and flour, and its main concerns are grain moisture, kernel hardness, particle-size grading and dust. Wet milling steeps the kernel in water, then separates germ, fibre, gluten and starch by grinding, screening, centrifuging and washing, and its main concerns are process water, effluent, the separation stages and the dryer that finishes the starch. A buyer should settle which product is wanted, how the grain will be bought and checked for hardness and mould, what grades will be sold, and what happens to the germ, bran, gluten and feed streams. At the smaller end of the capacity range, dry milling is far simpler to build and run than wet milling. This page describes both routes and keeps them apart.

In dry milling, the cleaned kernel is conditioned with a little water so the bran toughens and the germ loosens, then a degermer strips off bran and germ, which are oil-rich, and roller or hammer mills reduce the endosperm. Sieving by mesh size sorts the output into grits, meal and flour, so the sifters and the buyer's particle-size specification define a flour line. Grain dust and flour dust can ignite, so dust collection and explosion venting belong in the design. In wet milling, the grain is steeped in water under controlled conditions to soften it, coarsely ground to free the germ, and the germ is removed. The slurry is finely ground and screened to take out fibre, then centrifuges or hydrocyclones separate starch from gluten, and several washing stages clean the starch before dewatering and flash drying. A starch line is therefore a chain of steeping and separation steps with their own outlets, not a grinder with a dryer behind it. Wet milling uses large volumes of process water, often recycled counter-current to save it, and discharges a steep liquor that needs treatment. Kernel hardness affects grinding power, dust and the recovery of each fraction in both routes, and the germ, with its fat, must be kept out of the starch or meal.

Indicative Capacity Range

  • 1–20 tonnes feed/day

Key Specification Inputs

Starch recovery, water use, separation, dewatering, dryer sizing.

Technical Specifications

TechnologyDry milling to grits, meal and flour, or wet milling to starch with germ, fibre and gluten as by-products
Working PrincipleDry route: degerm, grind and sift by particle size. Wet route: steep, grind, screen and separate by density, then wash and dry
Grain SpecificationKernel hardness, moisture, cleanliness and freedom from mould, set in the grain purchase terms
Dry Milling EquipmentConditioning bins, degermer, roller or hammer mills and a plansifter, arranged to the grades required
Wet Milling SteepingSteeping tanks with controlled water, time and temperature before grinding
Starch SeparationHydrocyclone battery or centrifuges with fibre screens, with washing stages sized to the starch grade
DryingFlash dryer for starch; grain drying at intake where the harvest is damp
Product GradingMesh-based sifting for flour and grits; washing and fineness for starch
Dust ControlExtraction, filters and explosion venting at the mill, dryer and bagging points
UtilitiesElectric power for mills and fans, process water for the wet route, and steam, hot air or thermal oil for starch drying
EffluentWet route discharges steep liquor and process water needing treatment; dry route discharges mostly dust

Typical Process Route

1

Receiving, Cleaning and Grain Checks

Maize is weighed, sampled and cleaned of stones, cobs, dust and metal. Moisture, hardness and mould are checked here, because moist or mouldy grain cannot be corrected later in the line.

2

Dry Milling: Conditioning and Degerming

The kernel is moistened briefly so the bran toughens and the germ loosens, then a degermer strips bran and germ from the endosperm. Bran and germ left in the product darken it and shorten its shelf life.

3

Dry Milling: Grinding, Sifting and Grading

Roller or hammer mills reduce the endosperm, and sifters sort grits, meal and flour by particle size. The sifter plan fixes the grades, and dust control at this stage matters for both health and fire safety.

4

Wet Milling: Steeping

Clean maize is steeped in water for a long period to soften the kernel and loosen the starch from the protein. Steep time and water quality set the starch recovery and the load on the effluent system.

5

Wet Milling: Germ Separation and Fine Grinding

Coarse grinding frees the germ, which is taken out by hydrocyclones, and the remaining slurry is finely ground to release starch from the fibre. Germ left behind adds fat to the starch.

6

Wet Milling: Fibre Screening

Screens wash the starch and gluten away from the fibre in several stages. Fibre that slips through lowers the starch grade, so the screen count and wash water are checked.

7

Wet Milling: Starch and Gluten Separation

Centrifuges or a hydrocyclone battery separate starch from gluten, then wash the starch clean. Each wash stage uses water, which is why recycling and effluent handling shape the design.

8

Wet Milling: Dewatering and Drying

Starch milk is dewatered by centrifuge or filter and dried in a flash dryer to a stable moisture. Overheating changes the starch quality, so air temperature and feed rate are controlled.

9

Packing and Storage

Starch, flour or grits are bagged away from moisture and strong smells. Germ, bran, gluten meal and fibre each go to their own storage and dispatch route.

Process & Equipment Modules

  • Intake hopper, cleaner, destoner and magnet
  • Grain dryer and storage silo with aeration
  • Conditioning bins for dry milling
  • Degerminer
  • Roller or hammer mill
  • Plansifter
  • Steeping tanks
  • Coarse and fine grinding mills
  • Hydrocyclones for germ and starch separation
  • Fibre screens and washing stages
  • Starch centrifuge and flash dryer
  • Dust collection and effluent handling

Plant Output

Maize starch from the wet routeMaize flour, meal and grits from the dry routeMaize germ, the oil-rich fractionGluten meal and fibre feed from the wet routeBran and screenings from the dry route

Applications

  • Maize flour and meal for ugali, sima, posho and tuwo-style staples
  • Maize grits for breakfast cereals, snack extrusion and brewing adjunct
  • Maize starch as a thickener for soups, sauces, custard and baked goods
  • Maize starch for the textile, paper and adhesive industries
  • Feedstock for glucose and sweetener production
  • Maize germ as the oil-rich raw material for a separate oil plant
  • Gluten meal and fibre sold as animal feed ingredients

Key Features

  • Separate Routes, Separate Plants

    Wet and dry milling share the intake and little else. Specifying one route properly is better than a line that tries to do both on a small budget.

  • Hardness and Moisture Checks at Intake

    Kernel hardness drives grinding power, dust and recovery, and grain moisture and mould decide whether the grain is sound. A good intake section tests both before grain enters the line.

  • Germ and Bran Removal

    The germ holds most of the fat in the kernel. Removing it cleanly keeps flour fresh for longer and keeps the starch pure, and gives a valuable oil-rich by-product.

  • Water and Effluent Planning

    A starch plant uses and discharges much more water than a flour mill. Steep liquor, process water and starch fines must have a treatment route before the project is sized.

  • Dust Control and Fire Safety

    Maize dust and flour dust are combustible. Dust extraction, sealed transfer points, explosion venting and earthing are part of the mill, not extras.

Country Pages for Maize Starch & Flour Processing Plants

This product is listed on the pages of the countries below, each with its own enquiry route. Where Kadali has no office in a country, enquiries are handled from the Accra office.

Related Products

Frequently Asked Questions

What information is needed to size Maize Starch & Flour Processing Plants?
Start with the product: starch, flour, grits or more than one. Then state the maize supply, its hardness class, moisture at intake and tonnes per day, the particle-size grades or starch specification to be sold, the by-products you can sell, and the hours of operation. For a starch plant add the water supply, effluent limits and drying fuel available; for a flour mill add the dust and storage arrangements.
What capacity range does Maize Starch & Flour Processing Plants cover?
The indicative capacity range is 1–20 tonnes feed/day. It is stated on a feed basis per day, so restate your own volume on that basis and say how many hours a day the plant will run.
Should I choose wet milling or dry milling?
Choose by the product. Flour, meal and grits come from dry milling, which is mechanically simple and uses little water. Starch needs wet milling, which means steeping, many separation stages, a dryer and effluent treatment, and it justifies itself where starch or its by-products have a ready buyer. If cassava is also grown near you, starch from it needs no steeping, so compare it with maize starch using cassava starch processing plants.
Can rapid high-temperature drying damage maize before milling?
Yes. Drying too fast or too hot causes stress cracks, puffiness and discolouration in the kernel, which lowers milling efficiency and breaks more grain into fines. Dryer settings at the grain intake therefore matter to the mill. Ask the grain supplier how the maize was dried, and if you dry on site, specify gentle air temperatures and resting periods between passes.
What does a wet-milling plant produce other than starch?
It also produces germ, which is the oil source, gluten meal and fibre that go into animal feed. Each stream needs its own storage, handling and a buyer, and the value of these streams affects whether the project pays. The starch itself serves food, textile, paper and glucose makers, so confirm the grade each customer wants. A plant that makes starch but cannot sell its feed streams will struggle with disposal.
Does mould in the grain matter to the mill?
Yes. Grain that is mouldy or has been stored damp can carry mycotoxins that milling does not remove. They develop with warm, moist storage and pests, so intake sampling, drying and clean aerated storage are the controls. A mill should test and reject doubtful loads at the gate. Putting moisture meters, sampling and clean silos in the plan costs less than a spoilt batch of flour.
How does kernel hardness change the plant?
Harder kernels need more grinding power, and the dust formed and the share of each product recovered change with hardness. Both routes are affected, because the same grain settings will not suit hard and soft maize. Buying grain to a hardness specification keeps the mill consistent, and a supplier needs to know the usual grain class before sizing motors and sifters.
What happens to the water in a maize starch plant?
Wet milling uses a lot of process water, mostly for washing the starch and screening the fibre, and it discharges steep liquor that is rich in dissolved solids. Counter-current washing reuses water to cut the intake, but the steep liquor and any excess still need treatment before discharge. Settle the water source, the volume available and where discharge is allowed before choosing a starch plant.
How do I request a proposal for Maize Starch & Flour Processing Plants?
Use the Request a Quote page and describe your project. Decide whether you want starch, flour or both, your grain supply and the grades you will sell.

Enquire about Maize Starch & Flour Processing Plants

Send your raw material, target product and capacity to Kadali Africa Ventures for a technical proposal.

Request a QuoteWhatsApp