Dynamic differential temperature cooking
We take care of nature. Our programs always aim to treat a product optimally with as little energy and environmental impact as possible.
Why are meat and sausages being cooked?
Meat and sausage products are primarily cooked so that they have a longer shelf life. Small quantities can be treated in boiling kettles, i.e. hot water. For large quantities, saturated steam cooking chambers are commonly used in the industry. It has become apparent that the quality of the products can be impaired in various ways. In a cooking kettle, a product can quickly become too hot or the products are too long in it because the contact thermometer does not function reliably. This can also happen with cooking chambers – but the effects are greater there because more products are treated.
Over the decades, controls have improved with reliable watches and better temperature controls. The latest development – which, however, dates back a long time – is the precise control of the core temperature. Unnecessary cooking leads to high weight losses – too low a core temperature drastically shortens shelf life. For this reason, core temperature rules are used to attempt to achieve the shortest cooking time with the lowest prescribed core temperature. This ensures optimum shelf life.
A first step, and thus an essential start, is that the cooking process is either monitored with a recording device or directly via an appropriately equipped computer control system. If a recording device is available, it is possible to record the temperature curves for the core temperature and the room temperature and thus draw conclusions about the currently achieved F- and C-values. The step cooking program already brings some good success with regard to the C-values.
What is a Delta-T cooking program?
This is the further development of the step cooking program. “Delta” stands for difference and “T” for temperature. This means that a cooking program is carried out with a temperature difference. But what temperature difference is meant? We speak of the difference between the core temperature and the treatment temperature (chamber temperature). There is, however, no agreement among experts on the level of the difference. This is for a good reason. Here again the criteria already mentioned such as product dimensions, calibre and thermal conductivity values play an important role. Some prefer a Delta-T of 15 degrees Celsius, others of 20 degrees or 25 degrees. Therefore, a Delta cooking program is only good if this Delta-T can be set differently from program to program, i.e. arbitrarily.
The sequence of a Delta-T cooking program is simple for most variants:
- A batch of ham is to be cooked to a core temperature of 68 degrees Celsius. A cooking program with a Delta-T of 25 degrees Celsius is available. The maximum upper treatment temperature is 75 degrees Celsius. The initial core temperature is 12 degrees Celsius.
- After starting this program, the controller will maintain the treatment temperature in the plant unit at a constant 25 degrees above the measured core temperature. At the beginning a room temperature of 37 degrees is required. The Delta-T of 25 degrees is no longer maintained from the time when the core temperature plus 25 degrees results in more than 75 degrees. From this point on, the maximum treatment temperature is 75 degrees.
- This type of delta cooking brings a noticeable improvement in terms of cooking damage and energy consumption compared to normal stationary cooking or step cooking programs. The problem with Delta-T cooking: Depending on the product, product dimensions, calibre and thermal conductivity, the cooking process takes different amounts of time. This time span cannot be determined with these simple programs. Likewise, of course, the F-value that can probably be achieved is not known either, since the course of the core temperature is uncontrolled. These controls are available in the industry and correspond to what exists at present.