Cook-chill systems, very simply, cook high volumes of food and chill them very rapidly. What makes cook-chill unique is that the plastic bags in which the food is packaged are sterilized in the process. Since both food and package are essentially pasteurized, product coming off a cook-chill line has a typical refrigerated shelf life of 21 to 28 days.
What are the benefits of cook-chill in manufacturing? The ability to make large batches of food with a long shelf life can change the way you operate, for the better. Imagine a food
The cook-chill process lends itself to batch-cooking large quantities of product for storage and future use, or for distribution to multiple foodservice outlets. If you’re a multiunit operator,cook-chill can consolidate some of the cooking you do in individual stores, and the advantages of commissary cooking are impressive:
Quality. Remember, first and foremost cook-chill allows you to control product quality.
Instead of several cooks making several different versions of a sauce or soup or some other product, a cook-chill commissary can produce an item in bulk in a central location, guaranteeing consistency from unit to unit and from one day to the next. Because fewer people need to be trained how to properly prepare those recipes, quality and consistency are easier to maintain over time.
Sunset Foods commissary prepares everything from soups and chili to turkey and roast beef for its four upscale grocery stores, and one key reason the company moved to commissary production was to ensure consistency.
At the time Sunset opened its commissary four years ago, another issue affecting consistency was different equipment at the four different stores.
“The stores weren’t built at the same time, so there were different ovens and other equipment at each location,” Thompson explains, which affected preparation itself and the final product. The stores’ first signature item, Sunset turkey, needed to be consistent across all the stores, and preparing in via cook-chill accomplished that goal, he says.
Bulk ingredient purchasing for delivery to a central commissary location typically reduces food costs by as much as 10%. Cook-chill also improves food costs through higher yields (which we’ll touch on later) and reduced waste. Since foods are portioned into pouches, line cooks can take only what they need out of the walk-in.
Having a few people prepare certain items at a central location rather than many people making that same item in several locations saves labor right off the bat. That results in less need for supervision—even more labor savings.
You can’t beat the system in terms of sanitation,” says Hany Khalil, specialty chef at Borgata Hotel, Casino and Spa, Atlantic City, N.J. “In a traditional kitchen, you’re always taking a chance when it comes to employee hygiene, or cooking food to the right temperature, or preventing cross-contamination. With a cook-chill system, it’s all monitored.”
Basically, food doesn’t come in contact with employees from the time it goes into the kettle to be cooked until the time it’s plated or incorporated into a final dish. It goes directly from the cooking vessel to a sealed pouch where it’s chilled and stored or distributed to be rethermalized and served. And “cook-chill is very easy to set up and easy to write a HACCP plan for,” adds Steve Martinello, director of quality assurance at Legal Sea Foods, Boston.
By now, you might be sold on the benefits, but you’re probably wondering what it takes to get into cook-chill.
A cook-chill production system consists primarily of cooking equipment (steam-jacketed kettles or cook tanks), a pump-and-fill station and chilling equipment. Ancillary equipment includes a host of gizmos and gadgets—everything from pasta baskets to hoists and conveyors—to ease the process.
There are two variations on the process, one for liquid, pumpable products and the other for whole muscle meats or solid food products. Liquid product is first cooked and then bagged, and the portion-controlled bags (usually in half-, 1- or 2-gal. sizes) are rapidly chilled in a cold water bath. Whole muscle meats or solid foods, on the other hand, are vacuum-sealed in bags while still raw. They’re cooked in the bags, then chilled in a water bath.
We’ll take a look at the equipment you need for pumpable products first, then come back to meats and solid foods later.
A lot of you probably have a steam-jacketed kettle in your kitchens. They’re handy for making all sorts of soups, sauces and stocks. Imagine your kettle got zapped by the same radiation beam that turned Bruce Banner into “The Hulk” and you’ve got a good idea of what a cook-chill kettle looks like.
Kettles can be stationary or tilting, but the one thing that sets them apart from standard steam-jacketed kettles is a drain in the bottom. Constructed of heavy-duty stainless with insulated jackets, cook-chill kettles are capable of withstanding up to 100 psi steam pressure. They tend to operate most efficiently in the range of 20 to 60 psi. Some are sold with self-contained boilers, but more often you’ll have to spec and purchase a boiler separately.
YA 50-gal. kettle is usually the smallest you’ll find in a cook-chill facility. Most large operators use 100-gal. or 200-gal. kettles, but they typically range in size up to 400 gals.
Most kettles are the familiar hemispherical shape you’ve seen. One manufacturer makes conical-shaped kettles that it claims provide better heat transfer and faster cooking. Yet another makes a hemi-cylindrical tank (think 55-gal. steel drum cut in half from top to bottom, tipped over with the rounded side down). The shape’s advantage, says the maker, is more uniform stirring of product, making cooking more even.
One of the labor-saving aspects of cook-chill systems is programmable electric agitators built into most kettles. Rather than having an employee stir sauce in a stock pot on the stove, for example, agitators do the job automatically. They can be programmed for time and speeds ranging from 1 rpm to 210 rpm, and there are three types: vertical, horizontal and inclined.
Vertical agitators stand vertically in the kettle and sometimes are affixed to the kettle lid. They’re best at stirring liquids and scraping the sides of the kettle. Many have paddles or attachments that also lift product from the bottom of the kettle for more uniform mixing.
Horizontal agitators are actually attached to the interior sides of the kettle. The shaft protrudes through one side where it’s connected to the drive motor. This type of agitator does an excellent job of lifting and folding product for uniform mixing and even cooking.
Inclined agitators mount on the edge of the kettle so the shaft extends into the kettle at an angle. Most models tilt out, giving employees easy access to the mixing arms. This type also does a decent job of lifting and folding product, not just stirring it.
Once a soup, sauce, dressing, taco filling, (your product here) has been cooked, you package it at a pump/fill station. Manual or automatic, these stations are usually equipped with an air compressor. You hook up a sanitary line to the drain on the bottom of the kettle, and the compressor will pump product to the pump/fill station.
At a manual station, an employee fills plastic bags one at a time. Generally operated with a foot pedal, manual stations can be set to pump a metered amount of product. The station can be supplied with ready-made bags in a range of sizes, or with plastic tube stock.
You can choose to seal bags with metal clips or a heat seal. In either case, once the employee fills a bag of product, he or she inserts the neck of the bag into a slot. The machine will squeeze the air from the bag and then either heat-seal it or attach a clip.
Automated pump/fill stations can do most of this work without an employee present. These machines use either plastic tube stock or roll stock. Machines that use roll stock fold the sheet of plastic coming off the roll, heat seal it on the bottom and side and cut it to form a pouch. Once the pouches are full, they’re closed with heat seal.
Since the idea is to sterilize the bags with hot product while they’re being filled, many systems feature a temperature lock-out. If the product temperature falls below 180°F the machine won’t seal the bag.Roll stock is less expensive than tube stock or pre-formed bags, but heat-sealing equipment can be sensitive. If the stock is contaminated with food spills, it won’t seal properly. Clips are a little more expensive, but you run the risk of a clip falling into the food. Operators tend to start out with pre-formed bags and clips at manual stations, then switch to roll stock for automated stations when volume warrants it.
You can also add machines to the station that print labels with date, batch code and other information. Employees attach these to the bag. Some automated stations print information right on the bag before it’s filled.
One of the keys to the long shelf life of cook-chill products is the speed at which they’re cooled. Studies have shown that an 8-in. hotel pan of refried beans takes up to 20 hours to cool from a serving temperature of 140°F to 40°F in a walk-in. Meanwhile, most chillers can cool a kettle full of product from an even hotter 180°F to 40°F in less than an hour. In many cases, product is chilled in half that time.
Cook-chill chill tanks essentially use ice water baths. There are a few different types, but they all constantly circulate cold water for rapid chilling.
Tumble chillers operate a little like your clothes dryer at home. Instead of hot air, though, imagine cold water. There are two types: horizontal and vertical. In both types, a horizontally mounted, perforated stainless steel drum rotates inside a tank of cold water. (For some reason, vertical tumble chillers get their name only because they’re larger and tend to stand much taller than the “horizontal” type.)
The rotating drum “tumbles” the pouches of product in the cold water. This action mixes the product inside the bags so it cools more quickly.
These chill tanks (often doing double-duty as cook tanks) are insulated stainless tanks that simply use constantly recirculating cold water to chill product without a rotating drum. In many cases, however, they also bubble air up through the circulating water to gently agitate the bags of food.
These are long open troughs of cold circulating water. Designed for continuous chilling of one kettle’s contents after another’s, a variable-speed conveyor moves bags of product through the insulated tank of air-agitated water.
Just as you can run steam through a kettle jacket to cook food, you also can run cold water through it. A steam-jacketed kettle won’t chill products like a water bath, but they’re a smart way to keep refrigerated menu items like potato salad or chicken salad cold while you prepare and mix them.
So far, we’ve talked about a cook-chill system that cooks, packages and chills pumpable foods such as soups, stews, sauces, dressings and even pasta. Cook-chill systems also work very well for a variety of solid foods from prime rib roasts and whole turkeys to vegetables. The process, however, is just a little different.
To pasteurize solid foods and the packaging they’re chilled and stored in, they have to be cooked in the bag. Employees bag raw product first with whatever seasonings are needed. The plastic used for bag stock in this process is a little different, since it has to stand up to cooking. You also have to use a vacuum sealer to make sure there’s no air in the bag before cooking. Otherwise, the process is very similar.
A number of manufacturers have developed insulated steam-jacketed cook tanks that also serve as chillers. You simply put bagged product into the tank and the steam jacket heats water in the tank to a preset temperature, slow-cooking the product to whatever internal temperature you wish. Programmable controls monitor both water bath temp and product temp (with a probe thermocoupler). When the product is cooked, the unit automatically drains, refills with cold water and chills the food.
Typical sizes of these tanks are 100 gals. and 200 gals., and they cook anywhere from 500 lbs. to 1,000 lbs. of product at a time. Most use circulating water for both cooking and chilling, though some also use air agitation. There also are some tumble chillers on the market with a cooking mode.
The advantage is that you can slow-cook items like prime rib or stuffed pork loin overnight without any supervision. In the morning, the product will be chilled and ready to store.
A big benefit of cook-tank/chillers is that slow-cooking bagged product in a water bath provides much greater yield than traditional cooking. Typical yield on an oven-cooked prime rib roast, for example, is about 75%. Operators using cook- tank/chillers get yields as high as 97%. At $7 per pound, the savings can add up quickly.
The latest technology these days is all about modified cook-chill. Those who use the term are usually talking about using versatile cooking equipment like a combi oven to produce a wide variety of menu items, and then chilling those items quickly in a blast chiller.
There are two major differences between modified cook-chill and traditional cook-chill systems. The first is that in a modified cook-chill system, foods are chilled in open pans on racks in a blast chiller.
While blast chillers cool food fairly quickly, air-cooling food still takes far longer than using a water bath. A full blast chiller will definitely cool foods from 140ºF to 40ºF within four hours, faster than the FDA-recommended 6-hr., two-step method. It still isn’t nearly as fast as the hour or less in which traditional cook-chill products cool.
And, since food is usually cooled in uncovered pans, modified cook-chill systems don’t extend product shelf life beyond the five- to seven-day limits imposed by health departments. Because traditional cook-chill products are hermetically sealed in sterilized plastic pouches, they can be stored for weeks.
That leads to the second big difference. Modified cook-chill systems really don’t let you cook much past inventory. You pretty much have to use food almost as quickly as it’s cooked because of short shelf life. The idea behind traditional cook-chill systems is to create a food bank that individual units draw against. Production is based on keeping the food bank at par levels. In case of higher demand, product is available in the food bank to cover it.
Modified cook-chill offers advantages to operators who need to produce additional volume for special events like catering or banquets. Don’t confuse it with traditional cook-chill production, though.
