By Dan Bolton
The world’s top tea brands each manufacture more than a million tea bags per hour: Twinings, Typhoo, Tetley, and Lipton all operate factories housing hundreds of tea bagging machines that measure, fill, seal, and pack at rates exceeding 1,000 tea bags per minute, per machine and typically operate 24 hours per day.
Under these conditions, flimsy tea bag materials simply won’t do.
During a presentation at the recent Global Dubai Tea Forum, Dr. Mattis Gosmann, v.p. sales & marketing (composite fibers business unit) Glatfelter, stressed the importance of performance.
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He also revealed in-depth the process and components that make up the modern tea bag. The most basic are non-heat sealable filter papers made of natural fibers (abaca and wood pulp) with a small portion of wet strength agent to survive infusion. “Strengthening agents comprise less than 1% of a paper filter,” he said, but they are critical to “runability and machine efficiency.”
Natural fibers offer excellent permeability, enhance aroma and provide good particle retention—the challenge lies in closing the seams. Tea bag paper must either be tied, glued, or composed of materials that fuse. Food-safe glues leave a bad taste and are not practical for use in fast machines. Tea bagging equipment that folds and ties or staples tea bags shut are in common use.
To meet the demands of high-speed bagging machines heat-sealable solutions are the only practical option, explains Josep Payola, managing director of TerraNova Papers in Barcelona, Spain. The most common papers are natural materials formed over a grid of plastic threads. The paper adheres to the plastic which seals the edges tight when heat is applied.
An alternate method, used to make irregular shapes such as pyramid bags, uses ultrasound to seal a continuous roll of nylon. These machines operate at rates of 40-50 tea bags per minute.
Glatfelter recognized early the environmental concerns raised by discarding billions of tea bags, says Gosmann. That is why in 2003, the company became the first tea paper manufacturer to offer plant-based (corn starch) PLA fibers combined with natural pulp. The result is a biodegradable and compostable paper known as DynaGreen, explained Gosmann.
Last year a public outcry convinced PG Tips, the largest tea brand in the United Kingdom, to abandon tea bags that left skeletal remains of polypropylene plastic threads known as “fluff.” Wrexham home gardener Michael Armitage started the petition, calling on Unilever to make good on a promise that its bags decompose. More than 230,000 Britons, at a rate of 10,000 per day, signed an online petition that led Unilever to promise to switch to fully biodegradable, plant-based tea bags by year end.
Unilever says the new tea bags “will eventually break down into its natural parts” but advised the consumer to discard them in their food waste bins, not the backyard.
Armitage told the London Telegraph, “The gold standard for me is to produce tea bags that you can just chuck in your garden composter, and they would just disappear along with the rest of the garden waste.”
Gosmann explained that industrial composting facilities carefully manage temperature, humidity, aerobic and anaerobic conditions and the availability of organism to digest materials. “It is a managed method of waste disposal covered by international standards,” he explained.
At-home composting has inconsistent parameters.
Glatfelter’s tea bags are certified compostable under EN 13432, he said, placing Glatfelter “in the unique position to offer sustainable filter paper solutions for non-heat-sealable as well as heat-sealable tea bags.”
Composting marks the end-life its tea bags, but Glatfelter is committed to sustainability along the entire supply chain. Gosmann said the abaca used to make filter paper is grown without irrigation, fertilizer or pesticides and some are Rainforest Certified; pulp mills in the Philippines are vertically integrated, and Glatfelter supports family projects. The company provides FSC chain of custody and uses environmentally sound bleach.
“Glatfelter is committed to sustainability beyond paper,” he said, “the company is committed to a sustainable supply chain from seed to finished product.”