Millennia of history and innovation in a grain
Milling yields flour for human consumption and by-products for wholemeal products and animal feed preparation.
Milling is the complex extraction or purification process that works the wheat kernel, separating the endosperm – the key part of the grain for flour – from the other components, namely the bran and germ.
The process can be carried out using various techniques, ranging from the most modern to the more artisanal methods, and it consists of several stages. It requires a high level of expertise and specific knowledge of raw materials, along with meticulous attention to all production processes.
The main raw materials
Soft wheat and durum wheat
These are two different botanical species of wheat, each with distinct endosperm structure, nutritional values and uses. Soft wheat yields ‘fine flour,’ while durum wheat produces semolina, which is yellow-amber in colour.
Corn
Also known as maize, it’s a gluten-free cereal There are different types: dent, flint or vitreous, floury and sweet. From corn, we obtain grits, cracked corn, yellow flour – ideal for making polenta or corn flakes, for example.
Rye
This cereal is the closest to wheat. It can also adapt to very cold climates. It’s the only cereal, besides wheat, suitable for bread-making due to its high pentosan content. The bread produced is darker in colour.
Oats
Characterised by husked grains similar to wheat, it is made up of compound starch granules. It has a good amino acid profile from a nutritional point of view. The most widely cultivated variety is Avena sativa, which produces white and yellow grains.
Barley
With husked grains similar to wheat, barley is made up of simple starch granules. It is classified based on the number of grains per spike. The highest quality is distichous barley, which has two grains per spikelet.
Rice
The grain is coated with the ‘brown rice husk’. Due to its harvest period, rice, like corn, is often dried. It has a lower protein content and meets the demands of a growing market for products that cater to specific dietary requirements.
Sorghum
A cereal highly tolerant to drought, it can thrive in poor soil. Rich in antioxidants, fibre, and proteins, it can be used for food, animal feed and even biofuel.
Millet
A cereal found in arid and semi-arid regions, given its resistance to drought and poor soils. It is rich in minerals such as magnesium, phosphorus and iron, and fibre. Its varieties include pearl millet, Chinese millet and foxtail millet, each suited to different climatic conditions.
Soy
It is a legume belonging to the Fabaceae family (like beans, lentils, chickpeas and peas). Rich in protein and lipids, soy is distinguished by its high nutritional content and versatility in human and animal nutrition. Although it is not a cereal, it can be processed into flour or used in flakes.
The production process is divided into several stages depending on the raw material, the type of plant and the finished product.
Stage1
Grain receiving & precleaning
Once the raw material arrives at the plant, it is transferred to dedicated silos and undergoes initial cleaning. The silo connected to the mill typically ensures enough raw material for about 1-2 months of operation. The most common type of silo is vertical, and it can be made of concrete or metal. The storage systems are equipped with ventilation, cooling, drying systems, pre-cleaning devices for raw material preservation and mixing systems.
Stage2
Cleaning
The raw material is cleaned to remove residual impurities. This is essential to obtain good yields and high-quality flour. The cleaning process consists of several stages to prepare the grain for milling: first and second cleaning, followed by first and second conditioning.
Stage3
Waste grinding
The waste grinding section processes the residues from wheat cleaning – such as broken kernels, bran and dust – to recover their remaining value. The goal is to reduce waste, increase overall yield, and obtain by-products for alternative uses.
Stage4
Grinding
Before being placed on the market, flours and by-products are transferred to storage silos, complete with mixing plants and bagging and/or packaging systems (in the various formats required). The mixing system is strategic in order to make the best use of the different qualities of flour produced and guarantee customers a product based on their actual use. This translates into greater cost control and a better response to the market.
Stage5
Finished product management
Downstream of the production line, handling and palletising operations take place. This phase is fundamental for optimising the profitability of the milling plant. A carefully designed end-of-line system, with innovative solutions and taking economic factors into account, can significantly contribute to improving productivity and reducing operating costs, becoming a key element in the overall efficiency of the plant. These processes generally apply to many types of cereals, with appropriate diversifications based on their specific characteristics, for correct processing.
Stage6
End of line
The end-of-line section of an agro-industrial food processing plant is the final stage of the production process, where the finished product is prepared for distribution and sale. This phase is essential to ensure that products are properly packaged, labeled, tracked, and palletized, ready for storage or transportation. Typical end-of-line machines may include: packaging machines for packing products into bags, boxes, pouches, or other containers labeling machines; weighing and quality control systems, such as dynamic scales, metal detectors, and X-ray scanners; closing systems; palletizers, for neatly placing bags or boxes onto pallets; stretch wrappers, to secure and protect palletized loads with plastic film; shuttles and conveyors, to move products between machines. The end-of-line is often automated and integrated with digital systems to optimize productivity, traceability, and food safety.
In milling, there are many professional roles that play a crucial part in ensuring the effectiveness and efficiency of the process.
