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Just Chillin’

If you don’t use blast chillers in your operation yet, you probably will before long. You know what they are—refrigerators on steroids. If you watch the Food Network, you’ve seen chefs “set” a panna cotta in a blast chiller in 15 minutes. If you’ve eaten a banquet meal at a hotel in the past year, your meal probably was prepared in advance, blast-chilled and finished off hot shortly before serving.

So, why don’t you have one?

Until recently, you may have thought of blast chillers as a piece of equipment that a hospital might use as part of a HACCP plan, or that a B&I account or large hotel could use with combi ovens as a cook-chill system. Or, you may have thought of the small three- to six-pan countertop and undercounter units that have been introduced in the past several years, good for cooling down leftovers or consolidating production here and there, but somewhat limited in capacity.

In the past, too, blast chillers took detailed instruction to operate correctly, like the combi ovens they’re often paired with (and if you’re pairing a blast chiller with a combi oven, make sure the reach-in model accommodates the same size racks or opt for a compatible roll-in chiller). But that’s all changed since manufacturers incorporate features such as pre-set programs for different types of food, and touchscreen controls that guide users through easy-to-understand instructions.

Tell Me Why
Food safety is one of the most important reasons to get a blast chiller. The latest iteration of the FDA’s Model Food Code (revisions came out in 2015) still says the proper procedure for cooling cooked foods safely is to chill them from 135°F to 70°F within two hours, and from 70°F to 41°F within another four hours (a total of six hours).

However, the FDA has been placing increasing emphasis on HACCP as a way to mitigate risks of foodborne illness, and it’s likely that the 2017 Model Food Code will push more operators to adopt a HACCP food safety plan. While your employees can cool foods in a variety of ways that meet Food Code and HACCP guidelines, ice baths and frozen stir paddles aren’t as consistent or reliable as mechanical cooling.

Blast chillers are designed to bring the core temperature of food from around 160°F or more down to 41°F or less in about 90 minutes. Most units will freeze food in four hours or less. Cutting the time needed to cool food by 75% is a great benefit to any HACCP plan. And cooling leftovers faster means employees go home sooner at shift’s end.

Also, since virtually all blast chillers incorporate some type of HACCP reporting as a feature, record-keeping also is more automatic and reliable than counting on employees to fill out the time/temperature sheets required.

Consolidating production, another major benefit of chillers, can help you save labor and food costs over time. By cooking some of your menu items in bulk—soups, sauces, gravies, perhaps even some center-plate items—and chilling them quickly once a week instead of daily will save staff time, typically 30% or more. Preparing those items once a week also requires less supervision by chefs or managers, saving labor.

Buying ingredients in bulk along with reduced product shrinkage through lower evaporation from quick-chilling can reduce your food cost. And if you prepare menu items in advance and quick-chill or shock-freeze them, hourly employees can easily reheat them for service later instead of keeping salaried chefs on the clock to cook them from scratch. Briefly put, blast chillers can change how you bring food to the plate in ways that improve labor efficiency, food cost and safety.

Better Quality
If those aren’t reasons enough to consider adding a blast chiller to your equipment package, your staff will find a lot more uses for it than you imagined once given the opportunity to play with the technology in the kitchen.

Because they cool food so quickly, blast chillers prevent the loss of moisture that can occur when foods are cooled slowly. Food that retains its moisture tastes fresher when reheated and served. Quick-chilling also reduces the opportunity for bacterial growth that can occur in the “temperature danger zone” between 135°F and 41°F. Bacteria and other microorganisms degrade food quality as well as compromise food safety.

The sophisticated controllers in blast chillers these days also give you a greater degree of flexibility, letting you vary the way in which you chill foods depending on what they are. Chillers can quickly cool delicate foods such as seafood while maintaining quality and limiting moisture loss as easily as chilling pans of denser bulk foods. The benefit is not only better, fresher tasting food, but extended shelf life as well.

Prepared sandwiches, for example, chill faster with less moisture loss than in a walk-in, which means longer shelf life in a merchandising case, with crisper lettuce, juicier tomatoes and fresher tasting bread.

Many, if not most, models now also incorporate a freezing cycle. Again, due to the sophisticated electronics that monitor the cooling and/or freezing process, chillers shock freeze product fast enough to prevent the build-up of large, or macro, ice crystals in food products. Macro-crystals damage the food’s cell structure, which degrades quality and results in moisture loss when it’s thawed and reheated. Instead, moisture inside the food is frozen in micro-crystals, meaning food has virtually the same quality when it’s rethermalized as it did when it was first cooked.

Size, Power & Performance
Sizing the unit you need is your first order of business. Large operations doing a lot of baking or cooking likely will be using roll-in rack ovens that can be rolled into a blast chiller, too. Small operators, as mentioned earlier, likely will benefit from a small countertop or undercounter unit. But the vast majority of you, judging from category sales, will opt for a reach-in model.

Capacity of reach-ins is typically in the 10-12 sheet-pan and 20-24 hotel-pan range, or anywhere from about 85 to 200 lb. of food. Figure out what capacity you need by looking at the proportion of your menu that you’ll want to prepare and chill in advance. For example, take your most popular item—say a salmon entrée—and figure out what your highest volume of that item is per week. That will give you an idea of the maximum number of pans the chiller should hold at one time.

A caveat: units may be designed to hold 12-in. x 20-in. x 2-in. hotel pans, 18-in. x 26-in. sheet pans, or both. The more flexible the interior layout the more types of food you can chill with it. Also recognize that models made in European Union countries will likely be designed to hold hotel pans that measure just 12-in. x 20-in. x 2-in. The same hotel pan in the U.S. is actually 2½-in. deep, which may mean you’ll fit fewer in the cabinet than the specs indicate. It’s imperative you match the pans you’ll be using to the rack configuration of your unit.

You also may need more flexibility in the cabinet to make the most of its capacity. Some models let you adjust slides so you can put pans in with their length running side to side or front to back, or use half-size pans.

Unlike walk-in refrigeration, which is designed to hold cold food at 41°F or below, blast chillers actively remove heat from hot food to cool it quickly. Essentially the polar opposite of a convection oven, they use powerful compressors, large condensers and evaporators and fans to pump heat away from food. When you spec a blast chiller, typically the more power the better.

In this size reach-in segment of the category, most units have compressors in the range of 1½ to 3 or 4 hp. Like other refrigeration, systems should be balanced, but manufacturers use different strategies to speed the chilling process. Some have over-sized condensers and evaporators which help them run more efficiently as well as chill food faster. One manufacturer uses two compressors; both kick in to chill and/or freeze food, and the smaller of the two holds the product at the desired temperature until it’s removed.

Beyond size and power, however, performance will likely be the biggest factor in your decision. Power and airflow work together to remove heat from food, and how that happens can vary greatly from model to model.

No Hot Air
All blast chiller makers claim their equipment will bring product temperature down to a safe 41°F or less in about 90 minutes. Some units’ claims, however, are based on a starting temperature of 135°F, the minimum hot holding temperature in most health jurisdictions. Others claim to bring food temps down that fast from a final cook temp of 165°F. Remember, too, that some will chill a larger quantity of food than others in that time frame.

As with a range or fryer, you want the blast chiller you choose to have plenty of power, but that doesn’t mean totally sacrificing efficiency. Check to see if models you’re interested in have energy-efficient, variable fans. Also ask manufacturers to tell you how many Btu their units move per hour and at what amperage (and temperature, so you can compare apples to apples). While it isn’t easy to compare efficiency of one to another, units that move more Btu with the same amount of energy are usually more efficient.

Airflow is important in several ways. The larger the amount of air moved, the faster it will strip heat away from the hot food product. Makers use two or three fans to create consistency in airflow movement in concert with multiple ejection points from the evaporator. Some designs introduce cold air by blowing air over the evaporator coil, into the cabinet and over the product. Others draw the heat from the product, circulate it to the evaporator and then send it through the cavity and over the food. The methods may sound similar but the difference, makers say, is blowing cold air over the food to push heat out or drawing heat off of the food and then replacing it with cold air.

But all that air also can remove moisture, causing food to dry out. To minimize this effect, manufacturers use a few different design tricks. One line uses louvers to direct air in a laminar flow over and under each food pan, which the maker says is more efficient and less drying and requires no lids on pans. Yet another claims its “turbo” air circulation moves air in a more effective circular motion. And one says its fan, designed by an airplane propeller manufacturer, has more blades than any competitor, so it moves air more efficiently.

Chill Cycles
Another way in which you can ensure a blast chiller doesn’t dry out your food is by selecting the right chill cycle. Almost all blast chillers have at least two cycles—hard chill and soft chill. Hard chill is designed to bring down temperatures of any type of food as quickly as possible with high-volume air circulation at often sub-freezing temps. “In soft chill mode, most models protect quality by moving air at or above freezing temperatures more slowly through the cabinet. However, some models will use air chilled to as low as 24°F to accomplish even a soft chill cycle as quickly as possible.

Models also designed to shock freeze product will have a third cycle that circulates air at temps as low as -40°F to bring food temps down to 0°F in less than four hours. (In fact, shock freezers that don’t produce internal air temps of at least -25°F may not get the job done in that time.) Look for models that freeze food quickly enough to produce micro ice crystals, not macro ice crystals. Again, the larger crystals damage cell structure in food, and release water when food is thawed, resulting in lower quality food.

Blast chillers have followed a similar evolutionary path as combi ovens. Manufacturers have worked hard to make them easier and more intuitive to operate. Practically all models let you set a cycle by time or end temperature. Set the time or insert a temperature probe into the product, and the unit will automatically shut off at the end point, and usually hold the product at temperature until you're ready to remove it.

But most models now also let you select a cycle from a product menu (using icons and/or a written description, e.g., “roast chicken”). And many let you program the cycles you want for the items on your menu.

Probes And Controls
Further, many models also come with as many as three probes, giving you even greater automatic control over the cooling cycle depending on the food in the cabinet. The probes constantly monitor the core temperature of the food and adjust cooling accordingly, so a thinner product doesn’t freeze while a thicker product is cooling, for example.

Even more impressive are units that use probes with multiple sensors that accept multiple inputs. These probes are able to measure both the internal and surface temperature of food, giving the unit even more accurate data on the cooling process, so it can automatically adjust both air temperature and circulation in the cavity. This kind of fine-tuning helps maintain food quality. Probes for shock freezers are typically heated so they can be removed from the frozen product.

More advanced blast-chiller models also offer thaw cycles that can be controlled by manually setting a timer, or setting a timer automatically using a probe. Often, probes can be inserted in the hole left when the original probe was inserted during the freezing process. Other makers provide a small drill that makes a hole just large enough for a slim probe to control the thawing process. And two manufacturers’ blast chillers can actually proof and low-temperature cook or retherm thawed product.

Controls, too, are easier to use on most models than the last time we wrote about the category. LED displays that may use icons and/or worded instructions make operation easy to understand on both base and more advanced models. Many models now offer touchscreens.

Most units feature timer countdowns showing time left in a cycle, and you’ll find both visual and audible alerts for things like high/low temperature warnings, defective probe, high-pressure alarm (indicating a dirty compressor), unit malfunctions or HACCP issues.

As far as HACCP compatibility goes, most models provide a way to record chill or freeze cycles. Several models have onboard printers that print the results of each cooling or freezing cycle so you have documentation for your files. Other units also have electronic memory and data ports—either for a USB drive or SD card—that allow you to download the chiller’s HACCP data to a PC.

You can set defrost cycles on base models manually, but many now have automatic hot-gas defrost cycles that can be operated manually or on a pre-set schedule. Newer models incorporate sensors on the evaporator coil that kick on the defrost cycle when they detect freezing temps in the evaporator. Hot-gas defrost cycles eliminate the need for chillers to be near floor drains.

Cleaning typically is simple, too, since most units are well-constructed with 304 stainless. Several have mirror finish interiors with coved corners, making clean-up a breeze. And more models now offer UV sanitation lights as an option. One maker’s line uses an ionizer to sanitize, instead of UV light.

Since these are typically self-contained units, be sure to have employees keep condenser coils and air filters clean, too, for better performance. Models may have compressors and evaporators beneath the cavity or above it. Top-mounted models put controls up at eye level, and away from rising heat. Bottom-mounted models may be easier to service. Consider your operation and how each might benefit you if it’s important.

Finally, as always, look at warranties, availability of parts and the manufacturer’s service network to see if it’s compatible with where your operations are located.

Blast Chiller Gallery

Use this vertical reach-in blast chiller/freezer/refrigeration system, part of the QuickChiller line, to chill virtually any type of food, from delicate vegetables and seafood to hearty roasts. The unit boasts 4 operating modes: quick-freeze mode, soft-chill mode (for less dense items), hard-chill mode (for denser products) and a holding mode for chilled or frozen items. The eye-level touchscreen control gives you precise, programmable consistency at your fingertips. Program up to 20 preset menu selections.

The HurriChill blast chiller/shock freezer features a microprocessor to control a host of cycles including soft and hard chill, shock freeze, hold and optional thaw and UV sterilize. Air flows in an indirect, high-velocity pattern for even distribution. Under the thaw feature, frozen items return to a safe holding temperature by using alternating cycles of gentle heat and refrigeration; bring solid, dense frozen foods to 38°F in less than 7 hr. Accommodates Rational combi racks.

The patented Intelligent Food Recognition (IFR) uses a multisensor probe to sense product temperature at various depths and automatically adjusts blast chilling to prevent undesired freezing. Probe also triggers Smart On to turn unit on as soon as a probe is inserted. Unit features an infinity mode that allows the operator to set any combination of fan speed and temperature. Thaw mode also available.

A confectionary specialist, the Nordika 400 is suited to pastry and ice cream/gelato shops in addition to delis and restaurants. Unit blast chills and blast freezes (to 37.4°F and to 0.4°F) 123 lb. in 60 min. and features a heated product core probe. A hinged evaporator door, completely removable pan racks (hotel and sheet), coved corners and optional ozonizing sterilizer makes this chiller easy to keep clean.

Part of the ConvoChill line, this blast chiller/shock freezer features an integrated printer that prints out dates, temperatures and times during blast-chill cycles and shock-freeze cycles. The unit records data every 60 sec. for your convenience. Use the electronic control to hold up to 99 programs. The HACCP memory feature automatically saves alarms. The T14D is a companion piece to the ConvoTherm by Cleveland Range/Manitowoc Foodservice.

With touchscreen controls at eye level, HACCP reporting/warning functions standard (with printer) and a refrigeration system that slides right out for maintenance, the GBF-15 is a user-friendly blast chiller-freezer. The unit accommodates 15 sheet and 7 hotel pans minimum (recommended); 14 hotel pans can fit if needed. Defrost is automatic with hot gas and water condensate catch pan. Chiller brings 143 lb. to 37°F in 90 min.; 110 lb. to 0°F in 270 min.

This blast chiller/shock freezer accepts hot product directly from the oven; there’s no need to reduce food temperatures to below 160°F. The patented Cruise Cycle automatically controls the chilling process according to the type and size of the product load and prevents superficial burns; insert the probe inside the product and press “cruise.” For continuous bulk production, patented Turbo Cooling ensures the chiller works continuously at the desired temperature.

The control system on this blast chiller/shock freezer comes with improved precision in managing temperature systems. You can adjust temperature ranges per your requirements. Standard advantages of the unit include an interior cabinet with rounded corners and removable shelves and slides for easy cleaning, plus a self-closing door system with a stay-open feature when the door remains open past 95°. The door includes triple chamber gaskets and is easy to remove and snap back in for quick service.

MultiFresh combines chilling functions (cooling, freezing, thawing, chocolate) and warming functions (low-temp cooking, regeneration, pasteurization, proofing, holding), and now operates via MyA, a new touchscreen interface with 7-in. screen. Patented features include the MultiRack adjustable tray rack that doubles tray capacity; Multisensor 5-point probe (attached to the door) that can trigger auto-start and delivers perfect food temperature control; and Sanigen chamber sanitizing system. Data logging in the HACCP control software is wireless for easily downloading and reporting.

Master-Chill MBC models feature the patented Food Identification Controller (FIC) technology that automatically adjusts blast chilling cycles with its single, multi-sensor probe. Measuring temps at the core and on the surface, the chilling adjusts to prevent surface freezing and to preserve nutritional value. Multilingual LCD displays cycle based on time or temp, interior and product temp, ventilation speed and HACCP alarms. Foot-activated door opener is a one-of-a-kind feature.

The microprocessor control on the BFP121P is able to memorize up to 100 blast chill and blast-freezing cycles and memorizes any alarms triggered for HACCP monitoring. The processor controls up to 4 core probes, as well, for multi-food chilling. The unit’s compressor is protected by an overload-cutout switch, which cuts out the evaporator fan and compressor when the door is open. Accommodates 12 12x20x2.5 hotel pans.

This blast chiller operates the cooling system by either product temperature using food probes or by a designated time period. The unit’s controller comes standard with a USB port for downloading chilling times for HACCP programs. Randell offers an optional printer in lieu of the USB port if needed. Standard features include an automatic condensate evaporator, a self-closing door and adjustable pan slides.

So many features make this blast chiller/freezer user friendly. Eye-level touchscreen controls can hold 99 custom recipes. The self-contained refrigeration system slides out for easy cleaning and maintenance. A single multi-sensor probe is standard, but an additional heated core probe is an option. Unit includes a USB port to download HACCP data and unit diagnostics.

Designed from the ground up by the engineers at Thermo-Kool, the TK20-2 Blast Chiller & Shock Freezer has a unique, 3-way indirect airflow that combines with a multi-point-injection evaporator to deliver a consistent air temp over all the food in the compartment. The latest microcontroller technology delivers step-by-step instructions and diagnostics in a running 40-character, eye-level display.

This model boasts two compressors, including a ½-hp. maintenance compressor for holding product at proper temp. Blast-chilling is easy using Epicon Control. In automatic mode, you simply place a probe in the product and a chill cycle will start within 60 sec. For manual mode, you can program individual cycle parameters. Also in this mode, should you fail to correctly program the cycle or manually start it, Epicon Control will start a chill cycle based on default settings within 5 min.

Victory’s exclusive hi 5 unit is a blast chiller, freezer, thawer, retarder/proofer and slow cooker/warmer all in one. The touchscreen control displays HACCP alarms, including power failure and cycle time out of required temperature, and stores them in memory. The onboard recipe book holds 68 preset programs. Regulate the fan during cycles using the adjustable evaporator fan speed button.

This model features built-in alarms and can control the chilling process with temperature probes or a digital timer, which can be programmed with 2 preset chilling times for specific food products. The HACCP data logger system records, stores and prints temperature data for up to 7 days. The cabinet automatically defrosts and reverts to a +38°F storage mode after blast-chill cycles. The unit’s front-breathing design allows for 0-clearance installation.

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