Tea Premiumization Advances in Blending Technology

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By Peter Keen

The character of a tea is what drinkers remember about it and pick out as making it different and special. For loose leaf specialty teas, character mainly comes from the plucking, season, terroir, and processing method. Increasingly, though, it is a product of blending and flavoring.

A typical tea brand may blend teas from as many as 30 countries to get the best combination of appearance, flavor, cost, and consistency to make its own English Breakfast or Earl Grey stand out. Product developers invent exotic new teas that blend, infuse, and add flavorings: herbs, spices, fruits, flowers, nuts, essences, and extracts: Toasted fig is representative of the new recipes: puer tea, dried figs, dandelion root, coconut flakes, and fennel.

Such an ingredient range poses many challenges in meeting the core requirements of blending: first and most critically, it must be fully responsive to the tea taster’s judgment. As with wines, this where art precedes science and process. Those need to add consistency in production to the artist’s creativity in invention; it’s essential to a brand and a specialty that the taster’s recipe – which is often handled as a trade secret – be produced in quantity batch runs to an exact standard and character.

Every blend must taste as good as the one before. As the variety of ingredients increases along with concomitant differences in size, texture, density, chemistry, and ease of mixing, this is not simply a matter of pouring, shaking, and filling bags.

Tea Biz provides the example of maple sugar flavored black tea, “A big hit here in the Great White North [Seattle] that has eluded blenders for decades. On exiting a commercial “V” blender the mix seems well dispersed, but the sugar quickly settles during the packaging process and in transit separates into a sticky dense layer of maple underlying tea with no maple taste.” Blending such a tea demanded advances in appropriate technology.

Enhance versus automate

“Appropriate” here relates to the goal for the end product: the packaged tea. There is a wide gap between automating the blending of a low-end multi-sourced commodity to make a homogenized product and enhancing the premium elements of a mix.

In Sri Lanka, for example, there has long been a concern in the tea industry that importing cheap leaf for blending with locally-grown tea and re-exporting the mix damages the value of the “Pure Ceylon” reputation and premium value. The European Union banned the use of the Darjeeling name for imports that added Assam and Nepalese leaf to the blend. Dubai, a major port in the United Arab Emirates, has become the major global blending hub for re-exports. Largescale service facilities for warehousing, blending are a key stimulant to industry development. This is the explicit focus in Tanzania’s plans for making Dar es Salaam a tea hub, with major collaborative facilities announced in April 2019.

In all these instances automation is the focus and the priorities are scale, volume, efficiency and quality control. The enhancement approach emphasizes premiumization. James Mackness, the founder of Motovotano, a highly innovative custom packer of gourmet in Seattle, usefully summarizes the role of technology here as “synchronized real-time tea blending.” The focus is on flexibility and customization and the priorities center on choosing among increasingly varied components and capabilities.

Components of the technology base

The central component of a blending machine complex is the drum; fill it with the ingredients and rotate it to mix them. Drums can be huge, with carrying capacities of several metric tons. Standard technology employs a range of designs and methods to keep them filled, change batches, adjust speeds to suit the leaf, add liquid flavor essences, keep the mix clean – destone and remove minerals at the start and dust at the end of the cycle – and ensure adequate worker safety. They need variable speeds, typically 3-6 revolutions per minute (rpm), and feeding vanes to keep the leaf intact and unbruised. The process is largely controlled manually.

That is unsatisfactory for the era of premiumization and the variety of new flavors and ingredients, together with the demands of such regulation as the US FSMA (Food Safety Modernization Act), EU and Japanese import standards,  and HACCP (Hazard Analysis and Critical Control Points). It is also clumsy and inefficient.

Choice Organic Teas illustrates the path to better blending. From its founding in 1989, it has been at the forefront of innovation: the first in the US to offer exclusively organic products, 4 initially and around 80 today – each of which, of course, demands its own processing and blending recipe.

Here are the steps in its evolution:

• 1990s: Blending through a modified cement mixer, which had a capacity of 30 lb of tea. The main problems were stopping the machine periodically to deal with a “dead zone” in the middle of the mixer, where the tea wouldn’t blend properly or went unblended. The long mixing cycles damaged delicate leaf.

• 2000s: An upgrade to a rotary batch mixer “revolutionized” the process. Rotary blenders are gravity-driven with internal mixing flights that produce a dynamic, continuous tumble-turn-cut-fold action to ensure complete uniformity in just three minutes.

• 2010s to now: Newer rotary continuous mixers accommodate batch weights of 150 to more than 300 pounds, depending on the tea type. Some recipes require just 2-3 ingredients and others 12. Internal spray nozzles independently adjust liquid flavors and viscosity (bergamot essence in Earl Grey, for instance) and neutralize odors. Magnets and vacuums ensure a dust- and metal-free final blend.

There are many emerging improvements in not just the blending technology but separation and packaging. The workhorse rotary drum is being updated to balance speed with minimization of leaf damage, cleaning, rapid, and contaminant-free transfer between organic and non-organic batches, vertical/rotary/spinning cone column mixing, solids/liquid feeds/injections, discharge/emptying/bag filling, and many other design, material and operating advances. Then there are air purge amplifiers and wash out nozzles and vapor stream transfer of flavor volatiles.

Just handling the electrical connections and safety procedures is beyond the capabilities of many firms. The computer aspects compound the operational, skill and training demands: recipe control software, PLC (programmable logic controller) and SCADA (supervisory control and data acquisition).

Many will be provided on a service basis, rather than through in-house ownership. In early 2018, there were fewer than 10 blending facilities in Kenya. Most buyers and processors manually blend leaf from the western regions, with its bold color but low aroma, with eastern tea that has the converse characteristics. The four metric ton blender commissioned by one of the manual processors will be Africa’s largest.

Without technology access and capacity, Kenya’s smallholders are locked out of the premium export market. Siginon, the machine buyer, expects to provide 24-hour service to them at a cost of around seven cents a kilogram.

The seller, Van Rees, has brought similar services and technology to Sri Lanka, adding a dimension critical to premiumization and export growth: safety.

Existing manual methods and equipment meet the requirements for HACCP accreditation. Sri Lanka produces commodity broken leaf and quality large leaf. “Since the [premium] leaves are not to be broken, the blending is still performed by hand, or rather, by feet. Bags of tea are blended on the floor, by first piling the leaves up and then shoveling them. In the process sweat and other ‘non-essentials’ are inevitably added to the tea leaves. The workers, meanwhile, breathe in fine dust, produced during shoveling,” according to the company.

The new technology demands capital, training and special expertise when applied outside the blending of all-tea ingredients and the addition of nuts, candy, Andean rare herbs and floral infusions. These are process-centered with the technology a support to this. For lower-end blending, there a wide range of machines on the market, with customized recipe control and PLC features.

They generally comprise four types of system component:

• Recipe control software: Includes ingredient check lists (blend sheet), batch weight and instructions (blending speed and time, additives, amounts, etc.)

• Emptying and safety procedures: batch switchover, cleaning.

• Operator control interface: a tablet front-end with simple to use menus, displays and apps for monitoring and alerts.

• Programmable logic controller: this is a standard box in factories which use heavy duty equipment, are noisy, dusty, and heavily trafficked. A PLC is ruggedized and its programming languages, communication links, electrical connectors, sensors, etc., are tailored to the demands of integrating manufacturing equipment and processes.

• SCADA. This is one of the jargon terms for real-time information gathering. It’s of growing importance for supply chain transparency, authentication and conformity with such standards and certifications as Fair Trade, Rainforest-UTZ, HAACP, FSMA compliant, etc.

Blending is much more than mixing. It is a symbiosis of the grower’s craft, the human taster’s art and the technology’s delivery on the promise of them both. Innovation in flavor design rests on innovation in blending processes.

Technology is the enabling management resource.