Every healthcare foodservice operation should have a blast chiller if for no other reason than food safety. Serving an at-risk customer base, food safety is already a paramount concern. A blast chiller augments your HACCP program by dropping food temperature from 135ºF to 41ºF or lower in less than two hours.
Often, however, the food you need chilled is much warmer than the 135ºF stipulated in the U.S. Food and Drug Administration Food Code. It may have just come off of a steamtable at more than 145ºF or out of an oven with a surface or even core temperature of 200ºF. Many blast chillers can pull the temperature of those foods down to 38ºF in 90 minutes or less, and almost all of them can cool food from 160ºF to 38ºF in 90 minutes.
Those of you who haven’t yet purchased one may still think of them as expensive, bulky pieces of equipment that do one thing only. But blast chillers now come in all sizes and can do a lot more than cool food quickly. Their benefits are wide-ranging and potentially could have a huge impact on your operation in terms of food quality, labor savings and profitability.
The Right Cycle
Unlike standard refrigerators, which are designed to hold already cold food at cold temperatures, blast chillers are designed to chill or freeze hot food quickly. Most models now are capable of at least four out of five types of chilling cycles. Each has distinct benefits, so you’ll want to match applications in your operation to models that can accomplish them.
Soft chill. In this mode, units typically circulate 37ºF air through the cabinet, lowering the temperature without freezing the product. Variable-speed fans in most models typically run more slowly, moving air inside gently. This type of cycle is an ideal way to quickly chill delicate or thin food items, such as fish fillets, vegetables, desserts, etc., without blowing them or drying them out.
Hard chill. For more substantial foods— roasts, mashed potatoes, beans, etc.—the hard-chill cycle circulates subfreezing air as cold as 0ºF in some models, using higher fan speeds to strip warm air away from the surface of the product as quickly as possible.
Soft or quick freeze. In this mode, units typically decrease product temperature to between 0ºF and 10ºF by circulating air between -10ºF and 0ºF in the cabinet. Use this cycle to freeze most foods for storage.
Shock freeze. Not found on all models, but starting to appear on more as a standard cycle, the shock-freezing mode uses air that’s between -40ºF and -32ºF to quickly bring product temperatures well below 0ºF. Shock freezing is particularly good for products such as ice cream for a couple of reasons. First, freezing product super fast and at colder temperatures produces smaller ice crystals. These micro crystals are less likely to rupture cells, meaning the physical, organoleptic properties of the food are left virtually unchanged once they thaw. For example, if you freeze berries in a regular freezer, the cells will burst and you’ll end up with berry juice and pulp when they thaw. You get intact, juicy berries with a good shock freeze. Second, shock freezing hardens product such as ice cream so quickly that air churned into it doesn’t have a chance to escape. The air is what gives ice cream some of its creamy mouthfeel.
The shock-freeze cycle also kills parasites in seafood and is an accepted form of microbial kill instead of cooking according to the FDA Food Code.
Hold. All models should be able to hold product at temperature once chilled, frozen or hard frozen until you’re ready to put it in refrigerated or frozen storage.
The FDA Food Code gives you six hours to bring food temperatures down to 41ºF: two hours to lower the temperature from 135ºF to 70ºF and another four hours to get it down to 41ºF or lower. Most blast chillers lower food temps from 160ºF to 38ºF in 90 minutes or less, a 75% reduction in time recommended. That’s time your employees can spend doing things other than stirring an ice bath and monitoring temperatures. Maybe they can even clock out and go home, saving you money.
Taking food through the temperature danger zone (40ºF to 140ºF) more quickly obviously gives bacteria and other microorganisms less time to grow, resulting in safer food. Another major benefit of reducing bacterial growth is longer shelf life. Food that you quick-chill stays fresher longer. That translates to less food waste and lower food costs.
The reduced time blast chillers require to lower food temp also means there is less time for the food to dry out. Moisture retention in food means more flavor and less weight loss caused by evaporation. Manufacturers say chillers can help foods retain 15% more of their weight through the cooking process than they would if chilled slowly. Less shrinkage on big-ticket center-ofthe- plate items, such as roasts, poultry, etc., means lower food costs and more money on the bottom line.
Even simple grab-and- go items, such as salads and sandwiches, are enhanced with a blast chiller. Faster chilling slows bacterial growth and moisture loss, meaning foods have a longer shelf life in a merchandising case as well as better quality— crispier lettuce, juicier tomatoes, freshertasting bread and so forth.
The New Cook-Chill
Many healthcare operations have switched from old cook-chill systems, which cooked food in volume batches in steam kettles and tilting braising pans, then cooled them in water-bath tumble chillers. Instead, more healthcare kitchens are cooking from scratch and to order to deliver room-service-style foodservice. If you’re one of them, you may be wondering why you need a blast chiller.
Because quick-chilling retains and even enhances food quality, blast chillers enable you to cook products in advance and rethermalize them when they’re needed; they’ll rethermalize as fresh tasting as freshly cooked items. That’s a real boon for room-service-style systems where you need to get food out fast. If a patient orders something off hours, kitchen employees easily can reheat already prepared food in a combi oven, microwave or speed oven, eliminating the need for a chef or even line cooks at slower times of the day.
Several blast-chiller manufacturers also make combi ovens so that cooks can transport food from the oven to the chiller quickly and easily; some models of ovens and chillers accommodate roll-in racks. One pizza-oven manufacturer says pizzas made in its woodfired ovens actually taste better if they’re blast-chilled after the first bake and reheated in a speed oven right before serving. The preprep process gives the flavors time to marry, and the quick-chilling process holds the quality.
Like combi ovens, blast chillers let you customize the chilling or freezing cycle based on the product and the desired outcome. You can set most models to chill by time, temperature or product type. Also like combi ovens, most blast-chiller models come with food probes that not only make sure the product is being cooled properly but also give you the option of making the chill cycle automatic. (When the product reaches a programmed temperature, it triggers the chiller to change mode.)
Blast chillers also can reverse the chilling cycle, allowing you to properly thaw frozen foods in seven hours or less. At least one manufacturer’s line includes models that can raise product temperature to 130ºF, allowing the blast chiller to serve as a proofing cabinet for bakery items and even as a slow-cook oven in which you can cook delicate desserts or other items overnight and chill them when they’re done.
What To Look For
Size. Once you’re convinced a blast chiller is right for your operation, you’ll need to decide what size you need. Fortunately, blast chillers come in all sizes, from three-pan countertop units to big boxes that hold two roll-in bakery racks.
Most manufacturers indicate size by how many pounds of food a model holds. Small countertop units, for example, may be rated for up to 44 lb. Another way to judge what size you need is by how many full-size, 2½-in. hotel pans a unit holds. Small models hold six or fewer pans. Medium-size units typically hold 10-16 pans. Larger units hold 20 pans or more. To convert between pans and weight, figure about 12 lb. of food per pan to come up with a model’s capacity.
Also, most units now accommodate full-size (18-in. x 26-in.) sheet pans, but make sure the model you select has that capability if you need it. Some models also let you adjust the position of the pan slides in the cabinet for greater flexibility. Removable pan slides also make the interior as well as the slides themselves easier to clean.
Performance. Like walk-ins and reach-ins, blast chillers have balanced refrigeration systems. But because they’re designed to lower food temps quickly, not simply hold food at the proper temp, they typically have a lot more horsepower. While this makes them less efficient than refrigerators, manufacturers have incorporated a lot of clever tricks to make them more energy efficient over the years.
Efficiency. First, designers focused a lot of attention on airflow through the cabinet to cool food faster without drying it out. You’ll hear terms like “cyclonic,” “laminar,” “turbo” and “pull” instead of “push.” All are intended to move air quickly through the cabinet, but not blow directly on the food. Some makers also use two fans, and because most fans now are variable speed and use more efficient motors, air circulation has become more efficient.
Second, compressors also have become more efficient, and some larger models even use the new, more efficient scroll-type compressors. One maker uses two compressors: a large one to decrease product temperature quickly and a small one that kicks on once the desired temperature has been reached to hold it there.
Many models also offer the option of placing the condenser remotely, eliminating heat from the kitchen and generally allowing the chiller to operate more efficiently.
HACCP reporting. You’ll be hard-pressed to find a model on the market without the memory to record HACCP data. But on-board printers are standard on some models and optional or unavailable on others.
Defrost cycle. Less expensive models offer a manual defrost cycle that employees can run during off hours. Others offer manual and automatic defrost, so you have a choice. Some have a drip pan to catch condensate from the defrost cycle, but you may need to position your unit over a floor drain. The best option is a hot-gas defrost cycle that automatically runs when sensors detect that the evaporator is beginning to freeze; it doesn’t need a drain or condensate line.
Sanitation. At least two manufacturers offer automatic sanitizing systems for the interior of their chillers. One uses UV light; the other uses ionization. In both cases, you must manually clean the interior before using the sanitizing cycle.
Controls. Here again, it’s difficult to find models that don’t offer electronic LED or LCD control panels with intuitive operation and icons to guide employees. Most offer ways to program your own “recipes” for cooling particular food items just as you’d do with a combi oven.
Probes. Most models offer at least one food probe so you can chill food automatically via internal product temperature. However, some makes and models offer as many as three temperature probes, allowing the chiller a more accurate reading, especially when you’re chilling foods with different densities. If you’re chilling sous-vide products or freezing products, look for special probes that let you reseal packaging. For frozen food, some models have a probe that heats up to let you remove it easily from frozen food; others have a conical probe that easily pops out of frozen foods.
Service. Finally, compare warranties and service networks to make sure you can get the service and parts you need if your chiller ever breaks down. Most manufacturers also offer training support now because of the versatility of their chillers.
Blast Chiller Manufacturers
American Panel Corp.
Bally Refrigerated Boxes Inc.
Beverage-Air Corp./Ali Group
Electrolux Professional Inc.
Thermo-Kool/ Mid-South Industries Inc.
Victory Refrigeration/ Ali Group