When we find stems among the leaves of a tea, should we see it as poor sorting… or simply another part of the tea plant with its own qualities?

Open a bag of loose-leaf tea and look closely.

Among the twisted, rolled, or fragmented leaves, you may sometimes spot small light-colored, yellow, or brownish sticks.

Stems.

For many novice tea drinkers, their presence immediately raises doubts.

“Was my tea poorly sorted?”

The question seems logical. After all, when we talk about tea, we are almost always talking about tea leaves.

However, harvesting the tea plant is not simply a succession of independent leaves.

A bud and its young leaves are attached to a small portion of stem. Depending on the type of harvest, the processing method, and the desired level of sorting, this part can remain with the leaves, be removed later… or become the raw material for a tea of its own.

In Japan, this idea is even fully embraced.

Kukicha is precisely a tea made from stems and petioles separated during tea processing.

And behind this small stick that might have been mistaken for mere waste lies a chemistry that is actually different from that of the leaf.

1. Where Exactly Do the Stems Found in Tea Come From?

To understand this, we must go back to the time of plucking.

A fine harvest, for example, may consist of a bud accompanied by one or two young leaves.

These elements obviously do not float in the air: they are connected by a small portion of tender branch.

When this shoot is plucked, a part of this structure naturally accompanies the leaves.

It then goes through several processing steps.

Withering, optional fixation, rolling, oxidation depending on the type of tea, drying…

Then comes sorting.

As we saw in Tsuru No. 040, dedicated to leaf sorting , this step allows the different fractions of tea to be separated according to their size, shape, and desired characteristics.

The stems can then be partially separated from the leaves.

Their presence in a finished tea therefore depends notably on the desired standard.

Not All “Stems” Are Alike

A small tender stem from a young shoot is not comparable to a piece of old, hard, and heavily lignified branch.

The age and tenderness of the stem strongly influence its chemical composition and what it can bring to the infusion.

2. Does the Stem Have the Same Composition as the Leaf?

No.

And that is precisely where the subject becomes interesting.

Researchers compared the leaves and stems of Camellia sinensis harvested at the same stage of development.

They observed significant differences.

In the study published in 2022 in the journal Foods, the leaves notably showed higher concentrations of polyphenols, catechins, and caffeine.

The stems studied, on the other hand, contained more free amino acids and soluble sugars.

These differences were reflected in the cup.

Leaf infusions were more intense, more bitter, and more astringent.

Stem infusions were generally perceived as milder, sweeter, and richer in umami sensations.

Two Parts of the Same Tea Plant, Two Different Balances

These trends come from precise comparative studies. They do not allow us to state that all stems in all teas have exactly the same composition.

3. Does a Stem Contain Less Caffeine?

In the available comparative studies, yes: the stems analyzed generally contain less caffeine than the corresponding leaves.

But a nuance must immediately be added.

This does not mean that a tea containing a few stems automatically becomes a “decaffeinated” tea or even systematically very low in caffeine.

The final amount present in a cup depends on many factors:

• the actual proportion of stems;
• the cultivar;
• the age of the plant material;
• the type of tea;
• the quantity used;
• the water temperature;
• the steeping time.

The correct formulation is therefore simple:

Stems may contain less caffeine than leaves, but that is not enough to precisely predict the caffeine content in a cup.

4. Why Can Stems Give a Milder Sensation?

Mildness does not come from a single compound.

It results from a balance.

Catechins notably contribute to the bitterness and astringency of tea.

Amino acids, including theanine, can contribute more to the mildness and umami.

Soluble sugars also play a role in the overall perception.

When a plant material contains relatively fewer strongly bitter and astringent compounds and more amino acids and sugars, its infusion can therefore seem softer.

A 2024 study dedicated to a large-leaf yellow tea also showed that stems contributed to reducing the perception of bitterness and astringency in the studied blend.

Be Careful with the Word “Mild”

Mild does not necessarily mean sweet like a drink containing sugar.

In the vocabulary of tea tasting, it can refer to a less aggressive, less bitter, less astringent sensation, accompanied by a round, soft, or slightly sweet impression.

5. What Is Kukicha?

Japan probably offers the most famous example of the deliberate valorization of stems.

The Japanese Ministry of Agriculture presents Kukicha — 茎茶 as a tea made from the stem parts collected during tea processing.

It notably highlights its particular mildness and its easy-drinking character.

This completely changes the way we look at the question.

In this case, the stem is not tolerated despite its presence.

It becomes the sought-after product.

The parts separated during sorting therefore find a new destination rather than being automatically considered useless.

6. Kukicha and Karigane: Are They Exactly the Same Thing?

In Japanese commerce, denominations can vary by region and producer.

The term Kukicha generally refers to a stem tea.

The term Karigane is particularly associated with stems from higher-quality raw materials, often from the processing of shaded teas such as Gyokuro.

This distinction is important because it recalls a fundamental rule:

The quality of a stem tea also depends on the quality of the raw material from which these stems come.

A tender stem from a prestigious harvest and a coarse branch from very mature raw material are not interchangeable.

7. What If We Roast the Stems?

We then obtain another spectacular expression of this raw material.

In Ishikawa Prefecture, Kaga Bōcha is made by roasting selected tea stems.

The Japanese Ministry of Agriculture describes this tea as particularly fragrant, with a natural mildness.

Its production follows several steps:

harvesting, steaming, rolling, and drying, sorting the stems, then roasting.

It is during this last step that the aromatic profile changes profoundly.

Heat promotes the formation of aromatic compounds associated with roasted notes.

The Japanese Ministry notably mentions pyrazines, as well as certain floral compounds such as geraniol and linalool.

Kaga Bōcha: From By-Product to Regional Tea

The official history reported by the Japanese Ministry dates a turning point to 1902.

A Kanazawa merchant, Shinbei Hayashiya, then developed a method allowing the valorization of stems from tea processing.

The product met with success and eventually became a specialty permanently associated with the region.

8. Why Is an Old Stem Not Equivalent to a Young Stem?

The word “stem” hides very different realities.

A young stem is still tender and metabolically active.

With aging, its mechanical function becomes more important.

It gradually stiffens.

The study published in 2022 shows precisely that, when the tenderness of the stems decreases, several compounds associated with flavor decrease while the proportion of fibers increases.

The tenderest stems studied gave fresher and milder infusions than the older stems.

It is therefore impossible to judge the quality of a stem simply because it is… a stem.

9. Does a Lot of Stems in a Tea Mean It Is Bad?

Not automatically.

You must first know what tea you have before you.

In a Kukicha, an abundance of stems is perfectly normal.

In a Kaga Bōcha, it is even essential.

In a tea sold as composed exclusively of buds or carefully selected leaves, a high quantity of coarse branches could on the contrary reveal a less strict sorting than expected.

The defect therefore does not simply lie in the presence of a stem.

It may lie in the inconsistency between what the tea claims to be and what it actually contains.

How to Look at the Stems in Your Tea?

Ask yourself four simple questions:

1. What is the announced type of tea?
2. Are the stems thin and tender or thick and woody?
3. Are they present in a small quantity or do they intentionally make up the tea?
4. What do they actually give in the cup?

10. Can You Recognize a Quality Tea Only by Removing All the Stems?

No.

That would be as simplistic as judging a tea solely by the size of its leaves.

A tea is the result of a set:

• origin;
• cultivar;
• harvest;
• maturity of the shoots;
• processing;
• sorting;
• storage;
• preparation.

The stem is only one clue among others.

And this clue must be interpreted in its context.

Leaf versus stem

If you have a tea containing enough stems, separate a few of them.

Then prepare two very small infusions with parameters as close as possible:

one with the leaves, the other with the stems.

Do not try to decide immediately which is "better".

Instead, compare the intensity, bitterness, astringency, sweetness, aroma, and length on the palate.

"A good tea should not contain any stems."

The presence of stems does not, on its own, allow for the assessment of a tea's quality.

In some styles, their presence may indeed result from less thorough sorting.

But in others, they are deliberately selected to produce a tea with its own distinct identity.

Kukicha and Kaga Bōcha alone demonstrate that a stem can go from being a separated fraction to a true raw material.

The stem we forget

Take a small dry stem between your fingers.

Look at its color, its fineness, its breaking points.

Then observe a leaf from the same tea.

They come from the same plant.

Yet, each has played a different role in the teapot — and each can tell a different story in the water.

What we can take away

Stems are a natural part of the young tea plant shoot.

They can remain in a tea, be separated during sorting, or be used to create a specific tea.

Their composition is not identical to that of the leaves.

Several studies show, in particular, lower levels of caffeine and polyphenols and more free amino acids and soluble sugars in certain stems compared to leaves.

This can contribute to a smoother and less astringent infusion.

But tenderness matters greatly.

A young stem and a fibrous branch do not produce the same cup.

Finally, Japan demonstrates with Kukicha and Kaga Bōcha that the stem should not systematically be considered waste.

The leaf catches our eye. The stem, meanwhile, reminds us that a teapot is never limited to what we are accustomed to keeping.

Sources & verifications

The scientific and historical claims of this article have been verified using the following sources:

• Japanese Ministry of Agriculture, Forestry and Fisheries — presentation of the main families of Japanese green tea and Kukicha
• Foods, 2022 — Exploring the Quality and Application Potential of the Remaining Tea Stems after the Postharvest Tea Leaves
• PubMed — comparison of the composition and sensory profile of Camellia sinensis leaves and stems
• Food Chemistry: X, 2024 — influence of stems on the formation of the taste and aroma of yellow tea
• Foods, 2024 — study of non-volatile compounds present in tea stems
• Japanese Ministry of Agriculture — Kaga Bōcha: history, production, selection and roasting of stems