What is Batch mixing // what is Continuous mixing?
BATCH – batch mixing means all ingredients are (manually) loaded into a mixer for duration until they are homogenously distributed or mixed. After that, they are discharged and a new batch is being produced. Batch processing has been the chosen technology of the bakery industry for many years. The fact that batch mixing is the most widely used system does not mean it is the best choice for your particular application.
CONTINUOUS – a continuous process works based on the first in first out principle, whereby the composition and the mechanical behavior of the dough produced is constant at all times. Besides that, the process is characterized by a short residence time with lower energy consumption.
The rise of continuous..
Continuous mixing and other automatic dough mixing processes are gaining more and more favor, a growing number of bakery operators are considering a continuous approach to their Production process. When the first Industrial bakeries came into being, batch mixers could satisfy the bakers needs and wants. But as food demand grew so did the size of the food Production factories and conclusively Production output. Batch mixers became largers and ovens longer. Typically, the larger the batch of dough, the longer it takes to process the mass. The moment this line is stopped (for some reason) the dough produced by a certain batch will easily be lost.
As a result, newer technologies can produce larger quantities of dough (up to 12.000 kg/hr) in one and the same system. These continuous dough solutions are fully automated and require almost no manpower (Sobatech’s dark-room principle), accurate recipe control and a constant consistent end Quality. You must be thinking..why didn’t we hear of this technology sooner?
The answer is that until around 20 years ago, the continuous dosing technology was not advanced enough to feed the mixer at rates high enough to meet the demand of the continuous mixing process. The past two decades, this technology (the continuous dosing) has advanced immensely enabling an extremely accurate dosing of seperate ingredients into the continuous mixing system.
Consequently, more and more food producers question whether to choose batch or continuous mixing. On the one side, the long tradition of batch mixers and on the other side technology improvements and increased Quality demands of todays consumers.
TRADITIONAL MIXING – Batch mixing is seen as the most established and traditional way of blending raw materials – simply because these mixers were available when continuous did not exist yet. The development of improved mixing, controlling and metering resulted in continuous mixing systems that are reliable, easy-to-use and able to provide a consistent product Quality. Nevertheless, Sobatech understands that organizing your production process in a new innovative way can be exciting. Therefore, Sobatech has its own pilot plant allowing you to overcome possible perceived risks of changing to a new innovative type of mixing.
PRICING – A large misconception in the process of evaluating both processes is that continuous mixing is perceived to be more expensive than batch mixing. The rootcause of this misunderstanding lies in the fact that the cost of a continuous mixing system is compared to the cost of a batch mixer. A continuous mixing system obviously includes much more than solely the continuous mixer. If you compare solely on a mixer-to-mixer basis, you will conclude the price difference is nil.
Bulk delivery of raw materials. Generally, the same delivery systems can be used for both batch as well as continuous food processing (possibly pneumatic transfer from silo to receiver).
Dosing ingredients. the pricing difference between a batch or continuous system depends on whether you feed your batch mixer manually or automated. In case of a continuous mixing system, the dosing of raw materials is always done automatically at the mixer and requires greater automation and accuracy (the Quality is independent of the skills of the workers). Even though the initial investment of the automated dosing systems might be higher on a continuous mixing system – on the long term the improved metering technology will represent significant cost savings (Sobatech has proven that the same or better end-product quality can be reached).
Dough discharge. ‘Batches’ of dough typically come in a not-usable form, meaning that additional equipment is required to resize the batches. This additional proces step creates unnecessary shear and exposure of the dough. The continuous mixing proces creates continuous streams of dough that can be cut in-line if desired – there is no need for additional equipment that resizes the batches.
Naturally, the amount of savings related to a continuous system typically increase as production rate increases.
PRODUCT QUALITY – apart from the operational cost savings, many Industrial food producers prefer a continuous proces as it increase product Quality consistency and control. Typically a continuous Production line creates a dough that has minimized variations in development, homogeneity and temperature. Every piece of dough has to go through the continuous mixers in order to be discharged – meaning every piece of dough has had the same mechanical treatment. Besides that, the mixing chamber and mixing tools have a relatively large contact surface. This results in a constant (and controlled) development of the dough. Consistent doughs are easier to extrude and weight, while inconsistent doughs (due to amongst others the head and tail of a batch process) create variations in flow and varying piece weights with it (creating inconsistencies in packaging).