Continuous mixing requires less dough handling equipment than batch mixing: The method of handling dough after mixing is completely different with batch versus continuous mixing systems. In the case of continuous mixing, the dough generally comes out of the mixer in a rope or log. A cutter at the end of the mixer allows the baker to make any size dough chunks. The chunks fall onto a conveyor belt or directly into a hopper. In the case of batch mixing, the dough discharges from the mixer in a large mass that must be resized for downstream equipment, resulting in additional cost for this handling equipment.


As the requirement for dough increases, dough handling becomes a greater challenge with a batch mixing system. Larger chunks of dough mean more equipment, and more people. However, in the case of continuous mixing, dough handling is the same regardless of throughput. More efficient throughput – less dough


is at risk with continuous mixing compared to batch mixing during shutdowns: When a baking line is running, dough exists between the mixer and the proofing or forming


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equipment. This is referred to as dough-on- hand. This dough-on-hand includes dough in the forming hoppers, dough waiting to be placed in the hopper, dough being discharged from the mixer or the dough currently in the mixer. In the case of a batch mixer, this amount is typically around 2.5 to 3 mixer volumes. The issue for batch mixing is that all dough-on-hand is at risk should downstream equipment require an extended shutdown. In the case of continuous mixing, the hopper levels can be kept as low as possible to improve piece weight control, so only a few chunks are in transit. In effect, the dough at risk for continuous mixing is basically the volume of the mixer at any capacity. Automated continuous mixing systems eliminate variables that exist in the batch mixing process: Mixing systems inherently have variables which must be carefully controlled. Some of these include recipe, temperature, energy input, humidity, flour quality, and batch spacing. There are two steps required to control such variables – measurement and reaction to inconsistencies. It is how variables are measured and how the system reacts that determines the success of the mixing operation and


ultimately the consistency of the dough. In the case of batch mixing, the recipe is often based on hand-measured minor ingredients. So, the operation is dependent on a person and a scale.


In the case of continuous mixing, minors are blended with the use of loss-in-weight technology and a blender on load cells. All measurements are weighed automatically, and the data is saved in the system. Dry and liquid ingredients are metered into the mixer, and automatically weighed and recorded. As the mixer throughput increases, hand measuring creates greater opportunity for errors, more employees are required to batch ingredients and the pressure to create blends quickly increases. Continuous mixing guarantees accurate measurement all day, every day. It would appear that there is still no definitive answer to the question of whether to specify batch or continuous mixing solutions _ both still have a distinct set of pro’s and con’s and both have benefitted from technology advances. The choice, it seems, will still depend on the size of the operation, the budget available, and the product that is being produced.


Kennedy’s Bakery Production October/November 2024 33


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