CONTINUOUS DOUGH PRODUCTION
A continuous dough production process starts at the dosing of the raw materials (continuous weighing). After that, mechanical energy is applied to the mix of ingredients in order to equally distribute them over the complete mass (continuous kneading). Finally, Sobatech’s continuous bulk fermenter allows the dough to rest and develop taste, aroma and consistency (continuous bulk fermentation).
CONTINUOUS WEIGHING INGREDIENTS
Correct continuous weighing of ingredients is essential for reaching the required product quality. If the various ingredients are not dosed in the correct quantities to begin with, it will never be possible to produce a correct product. For that reason, Sobatech dedicated years of time and effort in developing the most accurate weighing technology available.
VOLUMETRIC VS. GRAVIMETRIC
(Dry) Ingredients can be dosed volumetrically or gravimetrically. A volumetric dosing system doses a given volume of material per time unit. The dosing speed of a volumetric feeder should be selected manually, which may vary based on the nature of the raw material input. A volumetric feeder is open-loop in a sense that it does not corrects to variations in the material’s density. A gravimetric dosing system doses the actual given weight of material per time unit. The weight is measured by using load cells which form the foundation of the entire system. In a self-calibrating gravimetric feeder system, the motor automatically alters its speed when a change is detected in the material flow. When using a gravimetric feeder to dose, you are in complete control of the quality of your final product.
LOSS-IN-WEIGHT VS. GAIN-IN-WEIGHT
Sobatech only works with gravimetric feeders based on the loss-in-weight dosing principles. This dynamic measuring principle is the most accurate weighing solution available. The feeders are located on digital load cells that constantly measure the weight reduction per time unit. Based on that information, the speed of the dosing screws is constantly controlled based on a closed loop principle. The system ensures an accurate flow of ingredients during both loss-in-weight (normal operation) as well as gain-in-weight (during refilling).
Sobatech’s software to control the feeder pump and other dosing hardware, ensures a continuous and accurate flow of both dry- and liquid ingredients of low, middle and high viscosity. Measurement equipment such as magnetic and Coriolis flow meters are used to regulate the correct quantity of liquid ingredients entering the continuous mixer. Sobatech can either tap the liquids from a circulating pipeline or from a storage tank.
A continuous mixing process by Sobatech uses a two phase process for mixing the ingredients into a consistent and homogeneous mass. As soon as all ingredients are evenly and accurately distributed over the complete mass (phase 1), the development takes place (phase 2). This is done in a controlled and extremely precise way during kneading. The production volumes range from 50 kg/hour to over 10,000 kg/hour. This can be accomplished in an employee free operational environment resulting in significant (labor) cost savings.
PHASE 1 MIXING: THE HOMOGENIZER
Both phase 1 mixing (the homogenizer) and phase 2 mixing (the continuous kneader) are based on the first-in / first-out principle. After gravimetrically dosing the powder ingredients, they pass through the homogenizer phase. In this phase the powders are, by means of medium pressure, injected by the liquid ingredients. The liquids enter the homogenizer in a pre-defined order. This non-mechanical way of blending the ingredients ensures a even hydration of the flour and better integration of the minor ingredients.
PHASE 2 MIXING: THE CONTINUOUS KNEADER
The contra-rotating mixing tools of the continuous kneader (phase 2 mixing), are responsible for the controlled flow of mass throughout the mixer. The combination of a relatively small amount of mass in the mixing chamber with a relatively high volume of tooling, result in a remarkable high energy efficiency. A large part of the energy developed by the mixer tooling is put into the product. The Sobatech continuous mixers have the ability to apply exceptional high shear forces during kneading.
CONTINUOUS BULK FERMENTATION
The Sobatech continuous bulk fermentation process allows the dough to rest for the development of taste, consistency and aroma. Time is a key factor within this continuous bulk fermentation process. Besides time, also ensuring each part of the mass is exposed to the same environmental conditions is of great importance in end-product quality and consistency.
TEMPERATURE, TIME & HUMIDITY CONTROLLED
At the outlet of the continuous mixer, there is a vertical belt to bring the dough into the continuous bulk fermenter tube. The fermentation time can be controlled by adjusting the screw speed in that tube. The set point of the speed is included in the final recipe. At the output of the tube, there is a divider that takes out the dough. The tube has a double jacket to stabilize the dough temperature. It is also possible to control the humidity in the tube. Combining time with an equal and controlled exposure to the right proofing conditions are the vital features of a Sobatech continuous bulk fermenter. Sobatech’s system control software allows to easily monitor and modify the temperature, humidity and speed of the continuous fermenter.