“Hold on, I’m coming”


Amongst avid tea consumers and many vendors, there is a bias against using machines to harvest tea leaves. This bias runs so deep that some use it as the primary indicator of quality. For example, consider the following observation:


“We recently swapped an invoice of machine harvested tea with an invoice of hand plucked, and guess what . . . The machine harvest invoice got the same price as all the other hand-plucked invoices, while the hand-plucked tea was discounted to machine prices.”[1]


Or this claim from a tea vendor website:

Hand Harvesting in Taiwan

“This estate does not use tea picking machines. Tea machines were invented in the 1950’s and by the 1970’s, most tea farms utilized them in some capacity to cut costs and expedite the harvest. However, the highest quality tea leaves must be hand-picked to ensure the top three leaves are intact.”[2]


Yet Nigel Melican, an expert the planting and management of tea gardens, and others point out that, driven by economic necessity, mechanical harvesting is increasingly becoming the norm.[3] Melican paints a future containing two broad categories of tea: commodity tea, which will be exclusively machine harvested and artisanal tea which may or may not be machine harvested.[4] Are we doomed, then, to an inevitable decline in the quality of our tea?


 The development of machine harvesting

Harvesting Shears

Mechanical harvesting devices range from simple hand shears to immense over row self-propelled behemoths that resemble the machine harvesters used in many of the world’s vineyards.[5] Japan has been the leader in the development and use of mechanical harvesters but they also are common in Australia, Argentina, Georgia and increasingly in India, China, Sri Lanka and Taiwan.


Japan developed the first mechanical harvesting device in 1910; essentially it was a large pair of shears with an attached collection pan.[6] These devices remain in use to this day but tend to render a chopped rather than full leaf. By 1960, Japan had developed self-propelled machines and ride on machines and nearly 90% of the Japanese harvest was undertaken using machines of one sort or another.[7] Today, Japan remains well ahead of most countries in the production and use of tea plucking machines.

Japanese self propelled tea harvester

In 1929 the Soviet Union imported machines from Japan and in 1930 began their own production.[8] By 1965 the Soviets had developed large ride on machines but, as these were only operable on gradients of less than 10% their use was confined mainly the plains. Machine harvesting accounted for only 40% of the tea crop.

Chinese robotic picking arm under development

China has been experimenting with mechanical harvesting since the early 1950’s but the use of machines has been slow to catch on there until recently.[9] Developments now, however are proceeding at a fast pace as the labor shortage in China becomes acute. The Chinese have designed electric powered clippers that eliminate the problem of exhaust fumes fouling the tea leaves. And, in a very interesting advance, the Chinese are developing a robotic plucking machine that uses artificial intelligence to detect which shoots to pick and a picking “arm” that mimics the plucking actions of the human hand.

Hand operated electrical tea harvester

Williames Selective Tea Harvester

Australia, with its very large tea plantations and chronic shortage of rural labor, has used mechanical harvesting since the beginning of the industry there. Historically these have been large combine like machines that ran over the rows. Recently, however, Geoff Williames has developed a “selective plucking machine” that will pluck at a rate of 92,000 plucks per hour. The machine, which is available in a ride on version and a two person walk along version, plucks only the mature shoots and leaves the immature shoots to develop for future pluckings. The machine has received extensive testing, with very promising results, in Kenya, Malawi and India as well as Australia. On the negative side, the machine cannot be employed on steeply sloped areas.


 But what about quality?


Organoleptic comparisons of hand picked and machine harvested tea are very difficult to find.[10] Nonetheless, we are able to make some judgements based upon leaf quality.


The primary complaint leveled at machine harvested tea is that it cannot have the precision of hand plucking and, among other things, leads to many broken leaves. Apart from appearance, broken leaves increase the surface area to water ratio during brewing and lead to faster and often more bitter infusions. Newly developed machines, however, do not result in broken leaves when used correctly. Williames claims that his machine will give leaf quality as good as or better than hand plucking.[11] The AI robotic machine being developed in China makes similar claims.[12]


I have not found comparative data that allow examination of these claims (indeed the Chinese machine is still under development) but Carr and Flowers have provided some data from other studies in their account.[13] Essentially, they report that, in terms of effects upon leaf chemistry, there is little to choose between hand harvesting and machine harvesting. Wu has reported similar results in Taiwan.[14]


Finally, there is one important advantage to machine harvesting that should not be overlooked; it is fast.[15] This speed allows harvesting at the optimal time of day in order to benefit from the best conditions for withering. In climates such as one finds in Taiwan, for example, prime withering time may be only a few hours per day.


So what?


The big so what is that labor shortages are real and getting worse in all tea producing regions. This, in turn, means that the cost of labor is going up dramatically. And that means that the price we pay for hand plucked tea will be rising sharply over the next few years; producers do not have the margins to absorb these increases, nor should they.


Unless, of course, growers find a cheaper replacement for expensive labor. That alternative does exist, in the form of machine pluckers. And as these machines improve in efficiency, the quality of the resulting made tea will rise. Mechanical harvesting already is the norm for top producers in Japan and for an increasing number in other regions. We need to make our buying decisions base upon what is in the cup, not on some preconceived notion that hand harvesting is necessarily superior to that done by machine.


That’s my take. What’s your view?


[1] Carr, M., & Flowers, C. (2018). Machine-Assisted Harvesting. In M. Carr (Author), Advances in Tea Agronomy (pp. 229-252). Cambridge: Cambridge University Press. doi:10.1017/9781316155714.013 p. 252


[2] This is from a vendor web site. I’ll not name the vendor


[3] Melican, Nigel (2017) Keynote address at the 3rd Annual GTI Tea Colloquium held at University of California Davis, DATE.


[4] Ibid.


[5] The hand picking vs. mechanical picking dialogue has been going on for years in the wine industry. A fun story, though likely apocryphal, concerns the First Growth Bordeaux property, Chateau Lafite. Evey harvest, it is said, a small team of hand pickers is stationed in the vineyards near the entrance to the property while in the bulk of the vineyard area at the rear, machines are busily gathering the ripened crop.


[6] Wu, Chia-Chang (2015) “Developing Situation of Tea Harvesting Machines in Taiwan” Engineering, Technology and Applied Research vol. 5 no. 6 pp 871 – 875.  It took me a while to understand what Wu meant by the “big scissors” practice. Amusingly, the Chinese characters for shears are大剪 (da jian) and in articles written in English by Chinese speaking authors this has been translated literally as “big scissors.”


[7] Wu, p. 871


[8] Wu, p. 872


[9] Han, Yu, et.al (2014) “Developing Situations of Tea Plucking Machine” Engineering vol 6, pp. 268 – 273


[10] Wu does cite one study undertaken in Taiwan, the results of which showed no significant differences. Wu, p. 873


[11] http:// williamestea.com/teaharvester.html and personal correspondence from Geoff  Williames


[12] Han, p. 271


[13] Carr and Flowers, pp. 241ff.


[14] Wu, passim.


[15] I am grateful to Chen Huan Tang for this observation.


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