Field to Cup: The 4 Steps in Tea Production

Can you grow tea in the USA?
A hedgerow of Camellia sinensis ready for harvest.

I’m sure you know that corn comes from the corn plant and apples from the apple tree, but did you also know that tea comes from the tea plant?

Tea is a plant?

Yes, tea is a plant. Specifically, it is the tea plant, Camellia sinensis, which grows naturally as a shrubby tree and is closely related to ornamental camellias so popular in gardens and urban landscapes.

And yes, tea is also a hot beverage. But every type of real tea—green, black, white, oolong, and pu’erh—begins as fresh leaves of Camellia sinensis and is perfected by expert tea makers who process leaves for each particular tea.

Confusion arises nowadays because any herbs, flowers, or fruits that get steeped in hot liquid are called “tea.” But as a tea drinker, it is important to know the difference between real tea and other types of infusions. Here today I am going to describe what camellia-derived teas is, how it is grown, how it gets manufactured, and how it ends up on the shelves of your tea merchant.

There are four steps in the process of getting tea from the field to your cup:

  1. Cultivation
  2. Harvest
  3. Manufacture
  4. Everything else

A detailed post could be written on each of these steps. For today, however, we’ll keep things basic and focus on the fundamental elements of making true tea. I believe that a little background regarding the tea industry may help you to explore your tea preferences in greater depth while also helping you to learn the parlance of tea. I’ll leave for a different post the discussion of how other types of “teas,” such as bush teas and herbals, are cultivated and manufactured.

Let’s start with the first step in this journey which begins in the tea field.

How tea is made
Camellia sinensis is often planted in vast tea estates.

Tea Plant Cultivation

Where tea grows

Tea has growth requirements that are found within tropical, sub-tropical, and some temperate regions of the world. Though tea is adaptable to a range of climates, most tea worldwide is grown in regions that are hot, humid, and rainy for at least half of the year. Locales with these environmental qualities can be found all over the world; for example, tea is grown productively throughout China, India, Japan, Sri Lanka, Taiwan, and even Argentina. North America also has a nascent tea-cultivation movement.

What tea farmers do

The first thing to know about tea cultivation is that the product of interest is the leaf of the plant. This is important because the tea farmer has to make decisions that favor the growth of foliage over the growth of tea seed. Tea fruit that contains seeds, when allowed to mature, is primarily used for propagation of tea plants and not for consumption.

To grow lots of quality tea leaf, the farmer has to consider many different factors. The amount of rainfall and its distribution across seasons, the efficiency of soil drainage, availability of minerals and nutrients, and the severity of sun exposure are just a few of the considerations.

To make things even more nuanced, each of the many cultivated varieties of Camellia sinensis may react to the same environmental factors in different ways.  For instance, a treasured tea variety that thrives in high altitudes of Darjeeling, India where winters are cool, may not fare too well in the low, sub-tropical tea gardens of Yunnan Province, China. The practice of farming is to find the best combination of local environmental conditions and tea variety for a particular area.

Growing tea for manufacture
Tea farmers often work long days in the field.

In for the long haul

The other important thing to know is that tea is a long-lived plant. High-quality tea leaf may be produced from the same plants for decades and perhaps even centuries. During all these years of growth, the farmer must tend the tea like it is a part of the extended family. Among many duties, farmers must prune plants to a proper shape, weeds have to be controlled, and fertilizers, composts, and amendments must be distributed. It is a lot of work to make a healthy tea plant, let alone manage an entire tea estate containing many tens of thousands of plants.

After about three years of growth since planting, farmers will begin to harvest leaf to explore its tea-making potential. An initial sampling must be done lightly so as not to cause the plant to divert resources from the developing root system or distort the plant’s emerging shrubby form.

And this brings us to the next step in tea production when farmers reap the “fruits” of their labors.

Harvest of Tea Leaf

Hurry up and wait

Leaf harvest for many tea varieties may begin in earnest in about the fifth year of growth. However, for some tea types such as pu’erh, leaf of young tea plants is not as desirable as leaf from plants that are decades older. In the case of pu’erh, the market value of finished tea may vary with the age of the mother plant, with tea made from the oldest trees fetching very high prices. The ideal timing of harvest with respect to plant age just depends on the type of tea that will be made from the leaf.

Pluck, pluck, pluck

Plucking of leaf may be conducted by hand or by machine. When plucking by hand there is precise control over the qualities of material harvested but with higher labor costs. Leaf that is plucked by machine, using leaf-shearing devices operated by one or two individuals, or by specialized tractors, has lower labor costs but at the expense of the quality of harvested material.

In general, you will pay more for hand-plucked than for machine-plucked teas. There are exceptions, of course, and when researching tea for purchase it may be worth your while to dig a little deeper into the details of harvest.

Tea leaf harvested by hand
Tea leaf plucked by hand is usually of higher quality than leaf harvested with machinery.

Shoots, tips & leaves

Not all tea leaves are created equal. For one thing, a leaf at the tip end of the branch is younger than all the leaves below it. Age of the leaf matters because the biochemical goodies that make tea unique—polyphenols and caffeine, for example—are more concentrated in younger leaves than in older leaves. This is why so much effort in the field is dedicated to encouraging tea plants to produce as many tender young shoots as possible. In fact, harvest is often coordinated with methods of pruning that induce plants to make “tippy” foliage.

A plucking that is classified as fine includes the leaf bud at the branch tip, the next two nearest leaves, and the main stem that connects leaf stalks and bud. A plucking considered coarse may include everything from the bud down to the third and fourth leaves and perhaps all the stem in between. A fine plucking is often called “two-and-a-bud,” whereas a coarse plucking is called “three (or four)-and-a-bud.” Fine material may be more valuable than coarse, but this will depend on the type of tea that is being made.

Leaves and buds of tea plants ready for harvest
The top two leaves and the bud leaf are usually the highest quality of tea material.

Timing is important during the harvest stage of tea production. If the manager waits too long to harvest then a fine plucking will transform into a coarse one and eventually lose its value altogether.

Woe to the manager who misses a harvest.

Processing of Tea Leaf

And now for the hard part

Tea leaf is now plucked and headed to the tea maker. Small-scale tea makers may process batches of just a few pounds of material whereas large-scale producers may be able to handle several tons.

The methods employed to process leaf depend on the type of tea to be made, the manufacturing facilities available, and the skills of the tea maker. Indeed, there is a bewildering number of ways to process leaf so let’s take an overview of the key stages involved. These stages may include withering, heating, rolling, oxidation, and drying.

Curiously, similar procedures have been adopted in the production of herbal “teas” made from rooibos and honeybush, two plants that are different from tea camellia in many regards.

Wither tea leaf?

Leaf begins to wither immediately after harvest. You have seen this same thing occur when you forget to put vegetables back into the refrigerator: a floppy stalk of celery is what you get for your neglect.

In the case of tea manufacture, however, some wither is often desirable. Black teas, for instance, may be allowed to wither up to 24 hours after harvest. Green teas such as those made in Japan, in contrast, are usually not allowed to wither any longer than the time it takes to transport the leaf from the field to the factory.

The main function of withering is to transform stiff, rubbery stem and leaf into soft and pliable material that resists breaking under stress. As you will see in the following section, however, withering is not the only way to make a leaf that bends to the tea maker’s will.

Withered tea leaf resists breakage
Withering softens tea leaf and prepares it for physical manipulation.

Heating up

Heat may be applied to harvested tea material for two purposes. First, leaf and stem of tea are readily softened by either steaming or pan-frying. If you have steamed or pan-fried vegetables then you have seen how rigid plant tissue is turned limp by application of high temperatures. Heat applied at just the right temperature will likewise soften tea material.

The other purpose of heat treatment is to deactivate chemical compounds within the cells of the leaf. If left unchecked, naturally occurring enzymes will catalyze reactions that radically alter the flavor and color of steeped tea. In green teas these reactions are undesirable and must be nipped in the bud, so to speak.

tea leaf heated in a wok
Frying tea leaf in a wok will stop oxidation and preserve the vegetal qualities of fresh leaf.

Heat applied above a certain temperature will stop enzymatic action and preserve the grassy flavor, or “greenness,” of tea leaf. This is why leaf processed to have a green quality is either steamed or pan-fried in the early stages of production.

Heat treatments thereby achieve the twin objectives of softening tissues and truncating enzymatic action. The further use of heat can be quite nuanced in the production of teas such as pu’erhs and oolongs.

Rolling along

We now have tea leaf that is pliable enough to resist breakage. At this stage, tea material may be physically manipulated, or rolled, so that cell walls and membranes are ruptured. Rolling in turn releases flavor-promoting substances normally contained within leaf tissues.

During hand-rolling, a grapefruit-sized pile of withered tea is held between the palms and a tabletop and gently rolled in a circular motion. In machine-rolling, tea material is pressed between two metal plates with the bottom plate stationary while the top plate moves in an elliptical path across the tea. The rolling and twisting forces applied in both methods cause tea juices to exude out of the internal tissues and on to the leaf surface.

The challenge here is to manipulate the leaf just enough to release the goodie inside but not so much that the leaf is mangled to a pulp. This is a delicate business and especially so when the material is rolled by machine. In any case, a nicely rolled leaf feels sticky and oily and has a fruity, nutty, or floral aroma. The aroma of rolled tea leaves is unforgettable.

Tea Oxidation Without Trepidation

The next stage of tea production is a resting period for the leaf during which oxidation occurs. Oxidation is a transformative chemical process that causes iron to rust and cut apples to turn brown.

The rolling of tea leaf induces oxidation. This is because compounds that are normally held in separate cellular compartments within the leaf are now mixed together. Key compounds involved in oxidation are polyphenols that react, while in the presence of oxygen, with the enzyme called polyphenol oxidase. It is from this oxidation reaction and its products that we obtain many different tea flavors. Colors of tea liquors (that’s the part you drink) also emerge from oxidation.

Oxidation of tea leaf
Tea leaf that has yet to oxidize will be bright green.

Oxidation is usually stopped after specific durations. This takes a lot of experience and a bit of courage to execute properly because the tea maker can ruin things here if the timing isn’t right. Teas such as oolongs, for example, are not allowed to oxidize for long, perhaps an hour or two at most. These teas are referred to as semi-oxidized because the tea maker stops the process when there is still oxidation potential remaining. Black teas, in contrast, are called fully-oxidized because most polyphenols have been transformed and there is little oxidation potential remaining on the leaf.

Oxidation transforms tea leaf into black tea
Tea leaf that has oxidized will be copper-brown and black.

What about green teas? Recall that in the case of greens, the heat was applied in order to soften the material and to cut off oxidation before it can begin. Enzymes such as oxidase are dismantled by high heat which is why green teas are considered unoxidized teas. The grassy, savory flavors of green teas emerge from compounds like theanine that are already present in the leaf at harvest. Rolling merely releases the green goodness onto the leaf surface where we can later liberate it with hot water.

Drying Tea Leaf for Keeps

The last stage in tea manufacture is drying. The goal of drying is to preserve the flavor profile that has emerged in the tea during withering, heating, and rolling. A dry leaf does not oxidize efficiently, if at all. Drying may be conducted in either a specialized oven or in the warmth of the sun which locks in the products of oxidation.

Sun-dried tea
Drying tea in the sun removes moisture and preserves the character of tea.

The shelf life of finished tea will vary with the level of oxidation. This explains why, under reliable storage conditions, fully oxidized teas will tend to hold their desirable qualities longer than unoxidized teas. Exposure to moisture and air will tend to cause a little bit of oxidative change in dry tea over time. In a few teas types, an evolution of flavor may be desirable but, in general, these changes diminish the quality of tea.

You will quickly learn how to protect your treasured teas from changes that lead to spoilage.

Everything Else in Tea Production

All that is left for the tea producer is to pack and ship the product. However, finished tea is not always uniform in shape and size and this variation can affect market value. Packing, therefore, involves sorting and grading before packing into bins of loose-leaf tea or chopped up into pieces small enough to put into individual, single-serving bags.

tea being sorted and graded by expert
Before sale, tea is sorted and graded by expert tea tasters.

Finally, tea is put into boxes and shipped to middle-men who eventually put it in the hands of your local tea provider.


That’s a lot of steps, isn’t it? Indeed, making tea is a significant undertaking that is every bit as complex as making wine or cheese or any other agricultural product that requires considerable time and mastery.

I hope that this sketch of how tea makes it from the seed to the shop is useful. Please use it to inform your next selection of fine teas.

Tea is consumed only after lots of work processing tea leaf
The prize that awaits.
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Mike enjoys teas from all over the world and he also grows and crafts his own tea leaf. And though they are loath to admit it, Mike has a PhD in biology from the University of North Carolina at Chapel Hill.

6 thoughts on “Field to Cup: The 4 Steps in Tea Production”

  1. One wonders about the agricultural practices of various growers, especially regarding fertilizers, herbicides, insecticides, and the like, as well as use of harvesting via machinery vs. hand-plucking. How are laborers treated? What sorts of activities (the possibilities must be daunting) are included in ‘everything else?’ How is the consumer to know what s/he is buying regarding these, and doubtless many other, aspects of tea production?

    • The short answer: know your farmer. Direct accountability is the only way to verify that your concerns regarding farm practice and labor relations have been addressed. This is, of course, a tall order for most consumers, especially in the tea industry where the farm may be located half-way around the world from the tea drinker. Some tea buyers/distributors do make a sincere effort to become familiar with their tea growers, but these operations are, sadly, few in number.

      My solution? I started my own tea garden. And now, I am accountable to myself.

  2. Hi Mike,
    I have swallowed your information on growing and processing tea like a hungry person being fed with banquet. I have a five year old Camellia sinesis in five gallon pot, the pleasure of seeing the beautiful white, fragrant flowers in early spring has rewarded me with years caring for it, but I also had wondered if I could make tea from it.
    After reading your detailed article, now I have a compass to follow through.
    I do have a question: Can I wilt the tea leaves in the dehydrator which has varies temperature settings? At 105F setting, will it kill the enzyme in the tea leaves? This way not only the leaves are wilted but also the green tea is produced. Could it be done?
    Thank you so much!
    Diana Wood

    • Hi Diana,
      Yes, your dehydrator will kill the enzymes in tea leaf, but you won’t have green tea from just that one step alone. There’s more to the process than that! One day I”ll publish a more detailed post on specific techniques in tea making, but for now, you can google videos on how to make green tea and go from there.

      Also, you’ll need a few more tea plants to make it worth your while. I recommend at least a half-dozen mature plants for growers who must stick with pots. Best of luck!


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