Blast chilling is a process whereby produce enters the chiller at or above room temperature – e.g. after being cooked – and is quickly brought down to a safe storage temperature, before being taken out and put into longer term static refrigeration. The purpose of blast chillers is to minimise the amount of time the food spends at mid-range temperatures where bacteria multiplication is at its peak.
In commercial food production, blast chillers have become an essential item of equipment, as a way of satisfying food safety regulations. But the process also directly benefits the food producer, by increasing the shelf life of its chilled products and increasing the productivity of its kitchens, since it speeds up the overall preparation time.
Porkka’s blast chillers are available in 5 sizes with a choice of chill only or chill and freeze capability, and are rated according to the volume of product which can be cooled per 90 minutes or frozen per 2.5 hours. The chill/freeze capacities of our models are as follows:
BC/BF 720SH: 30kg/90min or 25kg/2.4h
BC/BF 960SH: 60kg/90min or 35kg/2.5h
BC/BF 990SH: 90kg/90min or 50kg/2.5h
BC/BF 24-100SH: 100kg/90min or 55kg / 2.5h
BC/BF 48-200SH: 2 x 100kg/90min or 2 x 55kg / 2.5h
The larger blast chillers are designed to allow trolleys (GN 1/1 or GN 2/1) to be easily wheeled in and then wheeled out again once the desired temperature has been reached, and in between usage can be used for general trolley storage. The smallest model (720SH) is a “reach-in” cabinet which accepts Gastronorm 1/1 pans or trays and need to be filled manually.
The 720SH, 960SH, 990SH and 24-100SH are all single door models. The 48-200SH has two doors and a sliding dividing wall. This enables two batches of product to be chilled or frozen independently (both must be chilled or both must be frozen). As well as increasing overall volume capacity, this allows two different production lines to use the same chiller. It also allows just one of the sections to be run when production is lower, which keeps down running costs.
Porkka blast chillers satisfy all HACCP food hygiene regulatory requirements and include a food probe which is connected to the control system and stays inside the food during the chilling / freezing process. The control unit records the time taken to chill or freeze and the final temperature of the product. This information can be printed out using a Porkka supplied printer, providing documentary evidence for the producer’s own records or to pass on to customers.
The control unit also allows the operator to vary the chill rate according to the type of food being processed. Some foods need to be chilled at a lower rate in order to prevent the formation of ice on the surface of the food, while other foods simply need to be cooled down as fast as possible. The control unit comes pre-programmed with a standard blast chill program, but the user can specify and program in up to 8 different bespoke settings to suit their own particular needs. In addition, the chilling fans can be switched between half and full capacity to add further versatility. To add further control and confidence, blast chillers are fitted with temperature alarms and the progress of a cycle can be monitored visually.
Once a chill or freeze cycle is complete and the product is at the desired temperature, it may either be removed or kept within the chiller at a static temperature (known as holding mode) until it is ready to be moved to long term storage, or to await collection and transportation.