BULK HANDLING EQUIPMENT & SYSTEMS

Coffee

Overview:

Coffee is one of the world's most widely consumed beverages, valued for both its taste and the stimulating effect the caffeine content in the coffee has on most coffee drinkers. While commonly referred to as a bean, the coffee used to create the drink is actually the seed of the coffee plant. Coffee beans are a major cash crop and the leading export product for many equatorial-region nations. Approximately half of the coffee harvested in these countries ends up in the United States, which is the largest importer of coffee in the world. While an exact measure is nearly impossible, an estimated 150 million adults in the United States drink coffee, for an average of 400 million cups per day.1

There are two predominate types of coffee beans, Arabica and Robusta. Each contains distinctive oils and fats that determine the bean aroma and taste of the coffee beverage. The use of Arabica coffee beans results in a drink that is aromatic, light-bodied and more acidic than Robusta-based coffee. The Robusta coffee beans, which have a woody texture, generally produce a coffee that is stronger in flavor, sometimes having a chocolaty taste, with higher caffeine content than Arabica beans.

Coffee berries are still commonly picked by hand and allowed to dry. Machine washing removes the flesh of the coffee berry, leaving the coffee bean. At this stage, the coffee is referred to as "green coffee." After further drying, the next step in the process is the roasting of beans, usually at temperatures specified by the coffee manufacturer. This usual proprietary roasting process influences the taste of the coffee beverage by changing the physical and chemical characteristics of the coffee bean. The roasting also results in a decrease in density, as moisture is lost and volume increases. The density of the coffee bean also influences the strength of the coffee and its requirements for packaging.

 
Characteristics and Challenges:
When coffee beans are packaged for use by coffee bistros or aficionados that grind it themselves, preventing the degradation of the bean is of major importance. Damage to the beans could negatively impact the flavor and by extension, the reputation of the coffee. Coffee beans
may crack and lose their kernel if conveyed too aggressively. To prevent this, the equipment used to move the beans must be able to do so gently enough to avoid their degradation.

Flavored coffees, either in bean or ground form, present different challenges. Flavored coffee is often a very highly processed product that requires special treatment during handling. Enriched flavor powders may leave a product buildup in the convey line, which could affect the quality of the end product and will also create hygienic risks. For flavored coffee brands, the equipment must be thoroughly cleaned when handling separate flavors to avoid unwanted cross-contamination. To maintain pace with market demands, the processing facility operators should be able to complete a thorough cleaning in as little time as possible.

For ground coffees, keeping a uniform grind by preventing the segregation of fine and coarse particles ensures proper packaging of the coffee for retail sale.

If the coffee is being pneumatically conveyed into a processing system, the blower used to move the coffee though the convey line must be sized to meet the system. When conveying whole beans, care must be taken to maintain an air-line velocity that does not result in an impact forceful enough to cause damage to the coffee beans. For ground and flavored coffees, preventing particle segregation during this process is important. Coffee is abrasive either in full bean or ground form. This means equipment that can withstand coffee's abrasive properties should be used.

If the coffee arrives at the processing facility in bulk bags, the frames used to discharge the bags should be equipped with additional accessories to completely empty the coffee from the bag. This includes features such as spring-loaded frames that will stretch the bags, making them rigid and removing any accumulations of coffee lingering in the bags. Bag activating devices are usually effective in agitating the coffee, dislodging collections of coffee, promoting a better flow. Some of these bag activating devices also serve as a dust-tight seal between the bulk bag and the receiving hopper.

After the bulk bag has been connected to the receiving hopper and the coffee

Coffee
 
begins to flow, the air inside the hopper is forced out. Unless this air passes through a filter, airborne dust particles can escape into the surrounding atmosphere. A dust collector mounted on the discharger frame will contain the coffee inside the conveyance system. Coffee dust trapped in the filter media can be returned to the receiving hopper by a pneumatic pulse through the filter. This reduces the time necessary to perform the routine cleaning and sanitation typically required in most food and beverage processing environments.

Coffee beans are generally free flowing and will pass through most processing equipment without the need for flow promotion devices. Ground coffee on the other hand, will tend to interlock in hoppers, impeding its flow into downstream processing equipment. To promote flow, the feed hoppers and may need to incorporate devices such as mechanical agitators or vibrators.

Should the coffee used in processing be packaged in smaller bags, a bag breaking station with a dust hood, filtration devices and a pneumatic pulse cleaner is the recommended solution to support the manual unloading of the material. A hopper screen above the receiving vessel will help to prevent the introduction of foreign objects and protects the operators if the coffee is being dumped manually into a hopper that is equipped with agitating devices.

If a flexible screw is being used to convey the coffee, it is important to use a screw that matches the coffee's application requirements. Generally a screw with a wider and flatter profile will be effective in moving a material with coffee's characteristics to a filling machine undamaged and with no separation of blended products.

Should your coffee application feature the loading of material into bulk bags, the bag capacity will be maximized by use of a vibratory densification deck to level the
coffee as it fills the bag and by the application of load cells to achieve the desired weight. Seals and other dust containment devices will ensure a dust-tight operation.
 
 
Flexicon Applications:

A Flexicon flexible screw conveyor (also known as a helix conveyor, screw conveyor, spiral conveyor and auger conveyor) helped a Pennsylvania, USA specialty coffee maker improve the speed of its processing and convey disparate flavors with no contamination of the blends.

Flexicon's tubular cable conveyor gently slides materials through stainless steel tubing with minimal damage and is ideal for moving a material such as coffee. The tubular cable conveyor can also be designed with multiple inlets and outlets, making it an ideal option for a coffee packaging line. Flexicon's expert design and engineering staff will weigh each parameter and recommend the best solution for you. Upon request, Flexicon's test lab will simulate your coffee handling applications before the system is installed in your plant.

Flexicon's Dust Suppression and Collection Systems ensure proper containment of coffee throughout the conveyance process. Flexicon's BLOCK-BUSTER® Bulk Bag Conditioner loosens bulk solid materials that have solidified during storage and shipment, enabling bulk bag unloaders to discharge the material through bag spouts.

Flexicon's product line of advanced flow promotion conveyors, high flow hoppers, deaeration/ densification beds and a host of other components and accessories are proven performers that promote flow while reducing degradation, dusting and/or the separation of blends comprised of disparate particles.

 
1 Specialty Coffee Association of America
Sources: Where noted. All other information courtesy of Flexicon Corporation.

 

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