Cereal Flours and Meals

Wheat flour

The main aspects of wheat flour quality that affects biscuit manufacture is the protein quality and water absorption. To a lesser extent is the colour of the flour (the amount of bran present).

Flour is prone to insect infestation, particularly flour moth and weevils. If stored in damp conditions it may become mouldy. Infected and mouldy flour must be removed from the factory immediately and great efforts should be made to eradicate any insect infestation.

Quality tests for flour depend very much on what products the flour is used in. Some manufacturers have sophisticated baking tests. Because of the difficulty in testing flours for use in biscuits it is best to use flour from one supplier for each product. This means that if flour is purchased from more than one supplier try to designate which products are made from each supplier. Flours from different mills will always be at least slightly different.

Each year a quality problem arises with flour as the new crop of wheat is harvested and milled. The change is due principally to the fact that the wheat grains are new and fresh compared with those that have been stored for 9 or more months. However the quality may also be affected because the growing and harvesting weather has been better or worse than usual. The supplier should give warning of the advent of new crop flour and QC should be involved with production trials to use it.

Flour is delivered either in multi walled paper bags (usually 32 or 50 kg gross wt.), in reusable sacks of hessian or plastic weave or in bulk tankers.

Check the labels sewn into the seal at the top of the bags. If dough mixes are based on the use of whole bags of flour check that the weight of the bags is as expected, say 32 kg.

Bagged flour should be used within 4 weeks of delivery.

Bulk handled flour must be checked before the tanker discharges into the factory silo. Check the documentation that accompanies the load. It is just possible that the driver has brought a load of bread flour to you by mistake!

It is usually not possible to do many checks before the tank is unloaded so preliminary checks for colour and moisture are all that is practical. If more tests are to be made before the flour is used a sample of sufficient size must be taken for laboratory or baking tests. In addition to the laboratory tests it is wise to retain a reference sample (about 3 kg) of bulk flour until all has been used in the factory.

The moisture content of the flour may be affected slightly by the pneumatic handling because the blown air will be warm from the pump and there is a large volume of air relative to the mass of the flour being conveyed.

Flour in silos rarely empties completely. Some is held up on the lower walls and in this condition may become lumpy and a harbour for infestation. Inspections will determine how bad is the hold up in the silo and a clean down routine should be organised to ensure that no flour of more than 2 months age is retained.

Try to put the flour into an empty silo or at least into one that is very nearly empty. Blending of two flours in an uncontrolled manner may cause difficulties in the bakery.

Oatmeal and oat flakes

These materials are always supplied in multi walled paper sacks. The relatively high fat content of oats may give rancidity problems in storage. The oats will have been heat treated to stabilise them (destroy the natural lipase) but rancidity may occur by oxidation. Check the small of the oats.

The stabilisation process can cause variations in the water absorption properties of the oats and this will affect doughs where significant quantities of oats are used.