Barley Malting Process

Barley malt plays a fundamental role in beer production, offering brewers the choice to either obtain malt barley for in-house malt creation or purchase pre-made malt from malting companies.

The malting procedure for producing pale malt entails soaking the barley in water (steeping) until it reaches a moisture content of 42–46%. Subsequently, a phase of metabolic and physiological activity ensues post-germination, culminating in kilning. Throughout kilning, the malt is subjected to progressively hotter air for drying until it attains about 5% moisture, effectively arresting metabolic activity.

Malting is precisely defined as the regulated germination of cereal grains, with the aim of instigating specific physical and biochemical changes within the grain. This alteration is then stabilized through grain drying. Essentially, malting is a controlled germination process conducted to break down starch molecules and achieve specific levels of amylolytic and proteolytic enzymes crucial for brewing.

Three crucial steps ensure the desired transformations:
Steeping: This step is imperative for facilitating efficient water absorption by the grain, elevating moisture from 12% to at least 40%.

Germination: This stage is critical for sustaining embryo growth, synthesizing enzymes, and limiting endosperm breakdown.

Kilning: To secure product stability, kilning is indispensable, involving the malt being exposed to escalating temperatures.

The malting process ensures the accrual and release of diverse malt enzymes responsible for breaking down starch (α-amylase, β-amylase, limit dextrinase, and α-glucosidase), non-starch polysaccharides in cell walls (β-glucanase and xylanases), lipids (lipase and lipoxygenase), and enzymes that break down and release proteins (endo-proteinases and exo-proteinases).
Barley Malting Process

Cereal extrusion

Breakfast cereal manufacturing was one of the earliest commercial applications of extrusion cooking technology and remains one of the most widespread.

Extrusion technology was first applied to food materials in the mid 1800s, when chopped meat was stuffed into casing using a piston type extruder. In the 1930s, a single extruder as introduce to the pasta industry.

It is a continuous process by which food biopolymers and ingredients are mixed, plasticized, cooked, and formed by combination of moisture, temperature, pressure, and mechanical shear.

Extrusion cooking is very efficient technology used in the processing grains particularly in processing of breakfast cereals.

It is predominantly a thermomechanical processing operation that combines several unit operations, including mixing, kneading, shearing, conveying, heating, cooling, forming, partial drying, or puffing, depending on the material and equipment used.

During extrusion cooking, the processed materials undergo significant physical and chemical changes. By appropriate selection of process parameters such as temperature, moisture and processing time, the mass becomes entirely gelatinized and cooked.

Extrusion cooking is popular for ready to eat cereals, where which they are shaped, toasted, flavored, colored and sometimes enriched or fortified before being packaged and shipped to the consumer.

Cereal extrusion

Cereal Processing: History of Milling

The objective of cereal milling is to remove the bran and germ from the seed and to free the endosperm. This left whole as in rice milling, ground into coarse pieces (wheat semolina, maize grits) or milled into flour.

Since prehistoric times up to the middle of the 19th century, cereal grains were ground in small mills, driven by hand, wind or water power.

The process of milling wheat into flour was revolutionized around 800 BC in Mesopotamia, when animal, water and wind power were harnessed for the first time to run the large stones used for grinding.

In ancient Rome the mill and the bakery were the very same enterprise. The grain were milled and worked up without delay to dough and bread.

The flour ground in such a mill was whole grain flour, because the complete cereal grains poured into the mill on top, came out out as flour at the bottom.

Probably the most ancient technique involves the grinder rocking backwards and forwards while grasping an ellipsoid stone in both hands which crushes the grain within a larger concave stone suits in front of the grinder.

Both upper and lower stone are usually made from a hard igneous rock such as granite or basalt to avoid the production of stone in the grinding process.

Around the Mediterranean and possibly also in China during the first half of the first millennium BC, there were two sophisticated versions of the handmill the hopper-rubber and the lever mill.

Moving to the milling process proper, it was in 1878 that Henry Simon took 19 British millers, to Hungary to view the all steel rollermill invention.

This machine became the heart of what is known as the gradual reduction system, commonly used worldwide today.
Cereal Processing: History of Milling

Wheat Flour

Wheat Flour
High protein flour is desirable for some types of baked products, flour of moderate protein content for others, and high starches low protein content flour is desirable for still other baked foods.

The smaller flour particles are higher in proteins; the larger flour particles are higher in starch. Through air classification in a turbomill it is possible to separate flour particles into various size, which can be blended to provide whatever protein or starch content is required by the baker or other users of flour.

Turbomilling developed in the late 1950s, is considered to be significant milling innovation, because only through this process is the variety of blends for different products possible.

In the United States, wheat flour is enriched with the mineral, iron (as a salt). Enrichment with calcium salts is optional for some types of flour but mandatory for enriched, self-rising flour.

Wheat flour is use to make leavened products, such as alimentary pastes (macaroni, spaghetti, noodles, etch. Cake mixes are also prepared with flour, and flour is used for thickening canned and homemade stews, soups gravies and white sauces.

Various breakfast cereal products are made from wheat. Generally, in these products, the wheat is precooked an passed though heated rolls to form flakes.

It may also be shredded, or it may be heated to above the boiling point of water under pressure, with puffed wheat formed when the pressure is released.

Wheat bran may also be produced as flakes. High protein cereals may be produced from wheat together with added wheat starch sugar malt, minerals (such as phosphates), vitamins and other ingredients.

Some wheat flakes are coated with very thin layers of sugar.

Wheat Flour

Grain Milling Functions

Grain Milling Functions
Threshing removes the grain from the stem. However, the grain is not usually ready for cooking until the husk (glumes) has been removed. Wheat, sorghum and pearl millet usually thresh naked that is without the glumes. Maize is on a cob covered with a sheath: the sheath must be removed and the grain taken from the cob.

A combine harvester threshes the maize free from both sheath and cob. Barley, oats, rice and most of the small millets thresh with the glumes adhering tightly to the kernel so that even a modern threshing machine or a combine harvester cannot remove the grain from this husk.

The first step in any milling process for this latter group is to remove the glummer. This is done by rubbing the grains one against the other in a mortar or by simple rotary machine, by splitting off the glumes in a disk huller, or by use of rubber rollers rotating at a differential speed. The objective at this stage of milling is to obtain as high an out-turn as possible of whole grains.

Once free from glumes, all grains may be treated in the same way. Cereals have an outer layer and a gem, known collectively as bran, which is rich in lipids that rapidly oxidize to give off-flavors. The bran also tends to be less easily digested than the endosperm.

The objective of the second stage of milling is, therefore, to remove the bran. In the case of rice, the grain is required whole, so great care is taken not to break the grain. Most other cereals are eaten as flour or meal (a coarse flour). The more of the bran that is removed, the better the flour will keep.
Grain Milling Functions