There are as many as 400 recipes for producing different flours in the industry. Types of flour are not only dependent on factors such as bran and germ content or particle size, but are also reliant on wheat characteristics such as amylase activity, protein quality and quantity, hardness and moisture content.

An accurate assessment of these characteristics is essential for determining the end product quality and very important for meeting customers' demands.

Wheat Quality

At all times it needs to be remembered that wheat is a food ingredient used to make a whole range of food stuffs. It is therefore essential that wheat supplied to millers meets their requirements as well as any contract specifications. Upon delivery various tests are carried out to determine moisture content; protein content and quality; impurities; specific weight; and enzyme activity associated with grain germination. The specific variety of wheat may also be checked.

Intake tests are carried out in accordance with the nabim Recommended Code of Practice for Wheat Intake nabim. This sets out in simple terms how millers expect suppliers to treat grain, what suppliers can expect at grain intake and how any difficulties will be handled should they arise.

Wheat Preparation

When delivery is accepted, wheat is tipped from the lorry and transferred to the mill silo. Prior to milling the wheat is passed through the screenroom, to remove all impurities before it is milled.

The screenroom consists of a variety of sifters, aspirators, de-stoners and scourers, separating unwanted material based on the principles of size, shape, specific weight, natural peculiarity and air resistance. More information can be found in nabim's Wheat and the Screenroom textbook.

Once the wheat has been cleaned it is conditioned. Wheat is conditioned by the addition of water which softens the outer pericarp (bran) layer of the wheat and enhances the release of the inner white endosperm at the time of milling. This dampening process is often controlled by an automatic moisture measurement system, determining the exact water quantity required; based on the wheat's current moisture content and temperature.

Once conditioned, the wheat is rested within 'conditioned wheat bins' for up to 24 hours.

Milling

The milling process has evolved from the days of grinding the wheat between two large stone wheels, (although this process does still occur in a few mills) to the modern rollermill.

The modern rollermill consists of two cast iron rollers set slightly apart from each other. The top roller runs at a slightly faster rate to the lower roller; when wheat passes through it creates a shearing action, opening up the wheat grain.

The various fragments of wheat grain are separated by being passed through a complex arrangement of sieves. White endosperm particles known as semolina will be channelled into a series of smooth reduction rolls for final milling into white flour

In a typical mill, there may be up to 4 break rolls and 12 reduction rolls, which leads to the production of some 16 flour streams, a bran steam, a germ stream and a bran/flour/germ "wheat feed" stream.

The modern milling process allows the miller to remove the bran particles from the endosperm; grind the endosperm into flour; sift the ground stock and remove flour produced at each stage.

Blending.

Millers may blend different wheats prior to milling in order to achieve a specific grist. However, they may also blend different flours in order to produce the product demanded by their customers. By blending together the many different flour streams produced by the mill, a miller can create further variations in features such as flour colour.

Very white flours would come from the early streams only, while brown flours involve using most streams. Wholemeal flour is produced when all the streams, bran, germ and flours are blended back together with nothing removed.

Examples of the types of flours produced in the UK are: white bread flours; brown bread flours; wholemeal flours; patent flours; cake flours; biscuit flours; pastry flours; household flours; brewery flours; and flours for starch/gluten separation

Finally, the flour is sifted before delivery to the food manufacturer, bakery or retail outlet either in bulk or bags.

For more information about the milling process and the grain chain please visit www.fabflour.co.uk or www.grainchain.com where you can obtain this information on line.

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