Until the pasteurisation cycle is carried out in DONI®Therm/3/ module, the manufacturing process for the production of yogurt products with hard coagulum is identical to those of products with broken coagulum up to the pasteurization module DONI®Therm/3/ from where the cooled to fermentation temperature goes into the process tanks DONI®Process /5/. The production starter culture is then added in doses from the module DONI®Ferment Plus/4/ straight into the process tanks DONI®Process/5/. After a short intensive stirring cycle the dosing and packing of the product begins. During dosing and packing the stirring mechanism works at a low intensity to keep the product homogenous. If bulk starter cultures are used this process must finish with-in 20÷30 min to avoid coagulation in the tank. When dry starter cultures are used the process can continue for more than 60 min depending on their activity.
The unit is usually designed with three process tanks DONI®Process/5/, which operate consecutively with all DONI®Pack/6/ modules. The correct combination between the volumes of DONI®Process/5/ and the production capacity of the packaging modules DONI®Pack/6/ and their number ensures the continuity of the manufacturing process.
For this production method DONI®Process/5/ is supplied with a propeller agitator for intensive stirring and with a module for injecting sterile air into the free volume. The coagulation occurs in a chamber with a thermostat at a temperature of 42°- 45°С. After the product reaches the technologically necessary manufacturing acidity, it is taken out and quickly cooled down to a temperature of 4°- 6°С, which additionally hardens the coagulum. The capacity of the manufacturing unit will be limited to the hourly productivity of the packaging machines and the working schedule.