Fats and oils

Fats are delivered either in polythene-lined boxes or in bulk. Butter and butter oil is always in boxes. Oils will be in drums or plastic bottles.

Boxed fats are stable for several weeks if stored in a cool place. Any damaged boxes, shown because fat stains the cardboard, should be used without delay as metals in the cardboard will accelerate rancidity. It is useful if the polythene around the fat is coloured so that should pieces fall into the dough mixer they are more easily seen.

Bulk fat will usually be delivered warm and liquid. Check the taste from a tanker sample before starting discharge. This allows detection of any rancidity or off flavours and also the type of oil can often be perceived. An in-line filter should be used in the pipeline for the transfer from the tanker. New fat should not be mixed with old fat. Warm fat in a silo should never be agitated because that will promote oxidative rancidity.

The warm walls of a silo offer much opportunity for the onset of rancidity. If possible the fat should be stored under nitrogen.

To clean the silo use hot water with no detergent.