ARTICLES

Iced Tea Product Quality Demands Fast, Gentle Blending

CONCORD, NC — Despite the proliferation in the US of coffee shops, cappuccino makers and the rise of the bean-head society, tea still is, after water, the most popular beverage in the world. Preparation of fresh tea leaves determines tea type — green, black or oolong — and it is the blending of these different types, often in batch process machines, that produces one of the thousands of tea flavors on the world market. A tea blend can become the signature of one’s style, or that of an entire restaurant chain, in the same fashion as one might favor Kona coffee over French Roast.

While S&D Coffee of Concord, NC produces upwards of 100 million lbs of coffee annually, the company also handles a respectable volume of tea. A family business since 1927, the company has provided coffees, teas and juices to many restaurants, hotels, offices and vending system suppliers. Hot tea is actually co-packaged for the company, but iced tea product — not instant, but the type that involves fresh brewing — is blended in-house. S&D, in fact, supplies the iced tea product used at all McDonald’s restaurants, as well as providing for national chains such as Applebee’s and The Olive Garden. In recent years, S&D exceeded 10 million pounds and is reaching 25 million pounds of iced tea per year, requiring a three-shift operation.

Iced tea product can include up to 10 different, carefully selected components, according to S&D engineering manager Carl Teten. Besides having a flavor that holds up through brewing and chilling, an iced tea blend must arrive before the restaurant customer with minimal cloudiness. And nothing, says Teten, “blends our tea as well as our rotary mixer.”

For about 15 years, S&D has been using a 700-TS-110-MS rotary batch mixer, made by Munson Machinery Company, Inc., Utica, NY, to prepare their iced tea product, running batches of 2,000 to 2,200 lbs at a time. Since cut tea needs to be handled minimally (or else risk producing tea powder), it is to great advantage that the design of the Munson machine permits complete blending in just 2 to 3 minutes. S&D’s present production schedule calls for preparing batches of one blend over a four-day period, then switching to another blend. In between blends, the machine is cleaned of stray tealeaves and given an inspection.

The Munson rotary mixer is a low profile machine with a stationary inlet and an opposing stationary discharge, with a drum rotating on a horizontal axis in between. As the drum rotates, materials are charged via the inlet chute, and then internal mixing flights tumble and fold the batch materials with a multi-directional action. The gravity-assisted process quickly produces homogeneous blending while imparting minimal energy and intensity to the product. The blending action also directs the mix towards the discharge gate. When the blend is complete (typically no more than 2 minutes with most materials), the discharge gate pivots into the machine, where cone lifters gently direct the material out of the machine through the discharge spout. In short order, virtually 100% of product is discharged.

Continuous rotation throughout the entire blending cycle produces random dynamics that assures all materials remain in motion, preventing segregation in batches of varying material densities. The tumbling flow of material from the lifters and baffles creates an ideal environment for spray addition, coloring, coating, agglomerating and encapsulating (the rotary mixer at S&D was equipped with a spray bar, but the company has not yet used it, as their tea blends are produced without added flavorings). Additionally, the tumble/fold blending action also contributes to long equipment life without sacrifice of blend quality.

Tea mixing, typically 20 to 25 pounds per cubic foot, is a light load for the 700-TS-110, which is designed for batch volumes of up to 110 cubic feet (total volume 218 cubic feet). A low horsepower motor rotates the mixer, via a small, efficient helical gear reduction transmission and a final chain-and-sprocket drive. The drum is suspended on two trunnion rings riding on alloy roller assemblies. The machine has just one seal, located at the inlet and mounted externally for rapid removal and replacement, to contain dust.

While the former 10 million pounds of iced tea product (about 400,000 cubic feet) per year may suggest the satisfying of a lot of thirsts, S&D Coffee has raised production still higher. Teten, who has worked at two other coffee production houses prior to his present position, first examined the possibility of adding a second Munson mixer. What was found, however, was that by moving the original machine to a larger area of the factory, then re-sizing the support systems that load and unload the mixer, S&D is able to produce 10 million pounds of product per year in each shift, effectively tripling production.

“I have no doubt that this machine will still be running 10 years from now,” he said.



Finished tea blend exits the mixer. Since batch material is directed toward a discharge gate as the mixer rotates, evacuation is complete.



A low horsepower motor rotates the mixer, via a helical gear reduction transmission and a final chain-and-sprocket drive.



Each storage vessel holds a specific type of tea that will be used in a blend produced by S&D Coffee.



From this station, a technician controls the proportions for each batch of tea produced.



As many as ten iced tea components are blended in a Munson rotary batch mixer.