Batch blending consistency grows gourmet coffee bean business

BATAVIA, IL — The triple-tall mocha lattes, double-shot cappuccinos, half-caf espressos and other concoctions swelling the profits of gourmet coffee bars are testimony to the enormous — and growing — popularity of coffee. Since originating in the 3rd century in Ethiopia, coffee has grown into the global drink of choice, with demand estimated at nearly 8 million tons (7 million metric tons) per year. It is the most widely traded commodity in the world after oil.

Producing gourmet coffee is an exacting process requiring hand picking of "cherries" (the fruit of the coffee tree) removal of the outer pulp to recover the green beans (just two per cherry), and roasting of the beans. Roasting is a critical step, with various roasting times and temperatures producing different types of roasts — traditional American, Vienna, French, and the very strong Italian. Some coffee beans undergo decaffeination before roasting. Finally, gourmet flavorings such as French vanilla or Swiss chocolate may be added to produce the flavored coffees that are so popular.

A top Midwestern processor of gourmet coffee beans, the Papanicholas Coffee Company is a family-owned and -run business that prides itself on fine quality gourmet coffees. Business is growing, particularly in the area of flavored coffees, and the company offers more than 50 varieties of whole-bean and ground coffees.

To expand from the Midwest into select markets in the Northwest and Mid-Atlantic regions, the company moved into new facilities housing both corporate headquarters and a roasting plant with a capacity of more than a million pounds (454,000 kg) a year. At the heart of the plant are a new 2000 lb/h (905 kg/h) capacity Lilla roaster and two new Munson rotary batch mixers.

Roasting Creates the Flavor

The region and weather in which a coffee is grown determine its distinct flavor. Roasting the green beans brings out that flavor and develops the characteristic coffee aroma. The longer the roast, the darker the beans and the stronger the flavor until you reach the almost-burnt taste of a very strong roast.

"There are many intricacies in the art of roasting coffee beans," says Vaughn Papanicholas, Vice-president, "and it takes tremendous experience to maintain consistency." The Brazilian Lilla roaster is designed to roast evenly and provide immediate cooling once the desired color and aroma are attained. With partial cooling in the drum itself and in a cooling hopper to quickly drop the temperature of the roasted beans, the roaster protects the coffee's aromatic oils for better flavor and appearance.

Most coffee sold consists of a blend of several different types of beans to create a balanced coffee with desired taste qualities. According to Papanicholas, different types of beans from different sources are best roasted separately and then blended to deliver the optimal taste. "Although it's easier process-wise to blend before roasting, some of the beans will be under- or over-roasted. Blending after roasting gives much more uniform and consistent results."

Blending after Roasting Achieves Uniformity

In the old plant, mixing of the various types of beans occurred within the roaster, as vanes integral to the rotating vessel lifted and tumbled the beans. But variations in the density and moisture content of different types of beans produced corresponding variations in the degree to which each type was roasted.

Papanicholas overcame this limitation by roasting each type of bean separately, then blending roasted beans using a 50 cu ft (1.4 cu m) capacity stainless steel Munson rotary batch mixer. "The rotary mixer has a gentle tumbling action that does not break the beans or cause damage," he says. The gentle blending is a result of low-rpm rotation of the mixing vessel, unlike stationary horizontal mixing vessels with rotating ribbon blades, plows or paddles that push through the material, increasing friction, degradation and heat build-up.

Internal mixing flights of the rotary mixer alternate in direction for gravity-driven cascading of the material back and forth, producing a 100 percent uniform blend in three minutes or less. The flights also serve to direct the beans toward the discharge port, evacuating the vessel in three to four minutes with no residual in the machine.

The mixer has a stationary intake chute fed by a mechanical conveyor, and is fully enclosed, containing dust and preventing contamination of the product.

Second Mixer Conserves Flavoring

Papanicholas also purchased a 25 cu ft (0.7 cu m) Munson stainless steel rotary batch mixer for flavor spray coating downstream, replacing a continuous process coater of a different manufacturer. The rotary batch mixer is fully enclosed, a significant improvement according to Papanicholas. The old machine was open on both ends, allowing the flavoring to mist out, so there was a substantial amount of waste. Profitability benefits from saving this expensive component. The enclosed design also prevents flavorings from wafting inside the building, invading the non-flavored area.

Previously it was impossible to accurately measure the amount of liquid applied to the beans due to the lost liquid. With the new mixer, the operator weighs the coffee beans and flavoring for an exact blend. "Every batch is exactly the same with the rotary mixer," says Papanicholas. A typical batch of 442 lb (200 kg) requires about 13 lb (6 kg), or 3 percent, of liquid flavoring. Spray heads inside the mixer atomize the flavoring, and the gentle yet efficient tumbling effect ensures complete distribution without overspray or waste.

With a footprint of 7x10 ft (2x3 m) the rotary batch mixer fits in the same space as the continuous mixer while tripling its output because of the short mixing time. The mixer can coat up to 6 batches per hour of a flavor, producing 2600 lb/h (1180 kg/h) versus 900 lb/h (400 kg/h) in the old machine. A Clean-in-Place (CIP) system eliminates hand washing, reducing downtime between flavor changeovers.

Batch size may be varied with demand to as little as 10 percent of rated capacity with no variation in mixing time or uniformity. "We can run full batches of French vanilla all day long, but only need half batches of toasted cinnamon pecan, a lower volume product," says Papanicholas, adding, "The machine is also quiet, further improving working conditions."

Heart of the Papanicholas plant is a 25 cu ft (0.7 cu m) Munson stainless steel enclosed rotary batch mixer (left), a 50 cu ft (1.4 cu m) Munson rotary batch mixer (right), and a 200 lb/h (905 kg/h) capacity Lilla roaster (not shown).

This 50 cu ft (1.4 cu m) rotary batch mixer blends a variety of roasted beans to produce distinct coffee flavors.

This 25 cu ft (0.7 cu m) enclosed rotary batch mixer sprays roasted coffee beans with liquid flavorings.

Seen from discharge end, 25 cu ft (0.7 cu m) rotary batch mixer sprays liquid flavors while mixing roasted beans. The mixer is equipped with a Clean-in-Place system.

Papanicholas offers more than 50 varieties of whole-bean and ground coffees.

From its headquarters and roasting plant, the Papanicholas Coffee Company supplies gourmet whole bean and ground coffees in the Midwest and beyond.