Fluid-bed dryers prove the best at bringing home the cheese

When cheese company Castle Importing of California faced the problem that its traditional cheese drying system prevented a required increase in output, a Ventilex continuous fluid bed dryer provided the complete solution by trans- forming production rates while giving the drying process control needed to maintain quality.

In fact the Ventilex dryer, available in the UK from Orthos, is reported to be processing the entire previous weekly limit of some 2000kg of cheese in just an hour. A reduction in manual handling has also allowed labour to be rede- ployed with a consequent gain in productivity as well as output.

For 50 years the company had dried cheese by spreading it onto trays placed in a dehydrating room, and any change had to guarantee their high quality standards. Criteria included the initial moisture content the new method could handle, drying characteristics and hygiene as well as ease of use and production capacity.

The Ventilex continuous fluid bed dryer not only proved the most suitable of the different methods investigated, but its installation also greatly reduced the risks to hygiene and losses caused by accidents which were previously inevitable.

The first trial it passed was with mozzarella, which is an extreme case because of its high fat and moisture content. If drying temperature gets too high, fat drains from cheese of this type and it does not dry properly. The Ventilex dryer proved itself able to make a dehydrated product from the mozzarella without any departure from established quality standards.

Cheeses with moisture contents of up to 50% are now routinely processed in the Ventilex dryer. They are fed in frozen at -8?C, with an initial dryer air temperature of 38 to 40?C, and have thawed and begun drying when a third of the way through.

Full drying takes place in the middle section of the machine, where precise control of temperature and humidity ensures proper drying without fat separation. The cheese temperature is monitored remotely and held between 22.0 and 23.0?C while relative humidity of the air is controlled between the limits of 15% and 18%.

The third and final section of the dryer operates as a cooler using an air temperature of 6.0?C. Product leaves the dryer with a moisture content of about 27% and no loss of fat. It is then refrozen and subsequently milled for sale.

Residence time of Castle's dryer is adjustable from 15sec to 2hr, allowing a variety of cheeses with different characteristics to be handled. A computer- ised control system with a graphical interface allows the drying process to be checked and corrected, if necessary, at any time.

Even and consistent processing to ensure very uniform product quality is provided by the unique Ventilex low-frequency fixed stroke shaker conveying mechanism, which gives near-perfect plug flow. This means that the residence times of individual particles are held within very tight limits. The mechanism also eliminates stress cracking frequently associated with higher speed vibrating machines

So it is no surprise that Castle Importing is now said to be smiling even more broadly than ever before when they say cheese.

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