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Uniform Iced Tea Blends Achieved Using Rotary Batch Mixer

PEAPACK, NJ — Founded in 1912, Henry P. Thomson, Inc. is one of the largest tea importers in the US. Although it began on Wall Street (center of the tea trade back then), HPT now warehouses its products in Augusta, GA and sells primarily to tea packagers, who sell to restaurants, food chains and supermarkets in southern states.

"Many coffee roasters based in the South have complementary iced tea lines," explains Eugene Amici, president, Henry P. Thomson. "During the 1920s and 30s, HPT became the tea department for those coffee roasters, who have scaled up nationally since that time."

"Approximately 85 percent of HPT blends are for iced tea, which Americans increasingly choose as an alternative to carbonated beverages with less or no sugar," says John Smith, VP and managing director. "Iced tea is consumed in restaurants, made at home, and bought in the refrigerated sections of grocery stores and convenience stores," he adds.

A key to HPT's 100-year success is maintaining tea blend consistency — a difficult task due to sack-to-sack variations in imported tea. For example, says Smith: "We receive 400 sacks of an African tea, and from sack to sack the tea may be lighter or darker in color or vary in quality due to seasonal variations. Yet the customer expects blends that have no variation in quality from batch to batch."

To deliver this consistency, HTP relies on a Munson 140 cu ft (3.9 cu m) capacity Rotary Batch Mixer.


Evolution of blending at HPT

HPT previously outsourced its blending and packaging to a logistics company in New Orleans, but after the devastation of Hurricane Katrina in 2005, moved its blending, packaging and distribution services to an Augusta, GA warehouse owned and operated by RBW Logistics.

HPT first tried a ribbon blender, but found it "destroyed the tea" due to the ribbon blender's heavy action and high-shear rotation of the agitator, explains Smith.

Next, HPT purchased a custom-built mixer, but due to design and construction shortcomings, "It failed to reduce costs as expected," says Smith.

HPT replaced that machine with the Rotary Batch Mixer for several reasons according to Smith: The forward section of the previous mixer had to be tilted upward to promote evacuation from the discharge port, while the Munson machine remains level and discharges fully, eliminating wasted product and allowing rapid cleaning. Also, the previous machine had a topside shaft that bore a large amount of weight, while the Munson is supported by two external trunnion rings riding on heavy-duty roller assemblies, eliminating the need for an internal shaft with bearings and seals that could contaminate material and prevent thorough cleaning.

"The mixer occupies half the amount space required by the previous mixer, is more efficient, and can mix larger batches," adds Eugene Amici.

While the prior mixer processed a maximum of 1800 lb/batch (816 kg/batch), the Rotary Batch Mixer can blend between 1600 to 2600 lb/batch (726 to 1180 kg/batch). "The Munson machine can comfortably mix our daily output of 40,000 lb/day (18,160 kg/day), and can push to 50,000 lb/day (22,680 kg/day), if needed," says Smith. It runs every day, all day.


Tea blends require gentle, rapid mixing

Most blends consist of four to six teas, which HPT's suppliers process using either of two methods. One is a rolling process that twists the leaves, breaking them into sizes from 0.25 to 0.125 in. (6.4 to 3.2 mm) to powder. The other is a cut-tear-curl (CTC) approach that produces smaller, more uniform particles yielding more intense flavor and color.

At the warehouse, tea is received from suppliers in 90 to 140 lb (41 to 64 kg) sacks, which are opened by dropping them onto serrated teeth positioned above a vibrating screen, which removes oversize objects. A conveyor, outfitted with magnets to remove any metallic particles, transports the tea into the mixer.

The stainless steel Rotary Batch Mixer uses a gravity-driven mixing process in which internal mixing flights and lifters create a gentle four-way mixing action — tumble, turn, cut and fold — to produce a 100 percent uniform batch in one to three minutes, while imparting minimal energy to the material. The unit mixes continuously during loading through its stationary inlet, and discharging through its stationary outlet.

Observes Amici, "Everyone in the tea industry says Munson is the mixer of choice for its gentle mixing and other features."

Internal flights lift and direct blended product to the discharge gate, evacuating the rotating mixing drum, which is free of dead spots and shaft seals that could trap materials.

The blended tea is conveyed to a packaging station where a storage vessel holds one batch. While that batch is being filled into 900 to 2300 lb (409 to 1043 kg) bulk bags or 105 lb (48 kg) sacks, the next batch is being mixed.

Today some 70 percent of HPT's custom blends are purchased by restaurants, food chains, supermarkets and other smaller resellers. "To tea packers both large and small, our blending quality stands as one of HPT's core values," says Amici.




After passing through a vibrating screen (L), tea is conveyed to the 140 cu ft (3.9 cu m) Rotary Batch Mixer.



Internal flights lift and direct blended tea to the discharge gate.





The Rotary Batch Mixer blends 1600 to 2600 lb (726 to 1180 kg) batches and runs all day, seven days per week.



Despite sack-to-sack variations in imported tea, HTP relies on its Munson Rotary Batch Mixer to delivery consistent quality expected by customers.



Blended tea is packaged in sacks for shipment to customers.