2012

Degassing Valve Advancements 
Cut Coffee Processing Time

9 12 6 B

NickNewPhotoA new generation of degassing valves is helping plant managers, operations directors and packaging engineers to cut time and costs associated with coffee processing, while keeping products fresh throughout their shelf life.

The advanced technology consists of tri-layered, flexible valves that can be applied to virtually any location of a coffee package at high speed. This flexibility in placement opens up nearly any part of the coffee package’s surface area for promotional, brand or product content messaging.

The valve technology is the newest development in coffee degassing, a process that allows the escape of CO2 that would otherwise affect the freshness of beans and ground coffee. It caps an evolution that is predated by bin degassing and, more recently, hard button degassing valves.

The economics of the new technology are expected to boost the tri-layered valves over bin degassing and conventional hard button valves as the preferred degassing method for roasters worldwide.

Bin Degassing

Bin degassing employs open metal silos that contain roasted coffee and allow its CO2 to escape. The exposure to open air, however, can reduce the coffee’s freshness. Roasters can place a modified atmosphere above the degassing coffee to help retain freshness. However, the coffee does not remain as fresh as when packed immediately after roasting. The bin degassing silos incur a capital investment and maintenance costs. The process also requires holding work-in-process (WIP) inventory, sometimes for a day or more, and limits the coffee’s speed to market. Such business concerns led to the creation of degassing valve technology that emerged on the scene decades ago.

Hard button degassing valves allow processors to package and ship coffee immediately after roasting and grinding. The valve’s placement is typically at the upper portion of the package. The valves heat seal to packages at a rate of 25 – 45 per minute. The heat seal unit works in tandem with vertical form and fill machines that are capable of filling one-lb. bags at speeds of 65 per minute. Accordingly, the heat seal application of hard button valves limits the form and fill machine’s speed by 30 percent or more.

The actual degassing process involves CO2 pressure building inside the package, lifting the valve’s rubber escape disk and exiting the package. The heat seal process leaves a circular “scar” at the valve’s package location. In addition, packages may sometimes present a “brick” appearance subsequent to degassing, making for a non-uniform appearance of packages on store shelves.

Cost per valve and the application process’s relatively slow speed have traditionally undermined the hard button valve’s product freshness advantages. For that reason, roasters have had to carefully choose which applications would be economically viable.

21st Century Degassing Valve Technology

Tri-layered flexible valves apply to packages in a way that reduces processing time, leaves no “scar” and will not cause “bricking.” Supplied in rolls of 15,000, the valves apply via a high-speed pressure-sensitive valve applicator that integrates seamlessly into packaging lines. Unlike heat seal valves, the flexible valve neatly “wipes on.” The packaging line does not need to momentarily stop, as it does with each hard button valve. The pressure sensitive valve applicator keeps pace with the coffee packaging line’s filling rate of 65 per minute for one lb. packages, accounting for a 30 percent faster throughout compared with heat seal-based valve technology. It can also keep pace with much faster speeds, up to 120 per minute for fractional coffee packages.

The valve’s tri-layered construction presents a torturous path for the escape of CO2. In operation, as CO2 pressure builds inside the package, it enters and escapes through two of the valve’s layers, while the third remains sealed to prevent oxygen from entering the package. The system is sufficiently effective to keep residual oxygen at only two percent or less, a level that matches the industry standard. An added benefit: the flexible valves employ 90 percent less plastic than hard button valves, accounting for a 30 percent – 50 percent lower price and an opportunity for users to reduce their carbon footprint.

BOne major coffee processor recently adopted flexible valve degassing technology for jumbo fractional packages. Valve technology enables the roaster to bypass time consuming bin degassing. More, the flexible valve’s “pre-oiled” feature is a key factor in the processor’s speed to market. Valves that come pre-oiled have a precise amount of food-grade silicone oil at the necessary valve location to ensure protection against oxygen ingress. The pre-oiled feature can save time and reduce scrap and clean up by eliminating the need to oil valves during the packaging process.

Photo shows triangular-shaped, tri-layered pressure-sensitive flexible degassing valve positioned on the package to the left. (Photo courtesy of Avery Dennison Designed and Engineered Solutions.)

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