Same Material, Different Purpose: Why Chinese Incense Materials Are Processed Before Blending

Why are Chinese incense materials processed before blending? Because the same raw material can behave very differently depending on how it will be used. In traditional Chinese incense, preparation—often discussed through the idea of paozhi (炮制)—may reduce harsh smoke, moderate excess oil, improve combustion, or help an ingredient integrate into a formula without erasing its own character.

This article uses Jiangzhenxiang as a workshop example: oiliness valued in medicinal material can become heavy smoke when burned, so the maker reduces part of it rather than removing everything.

A few days ago, while answering a comment about Jiangzhenxiang (降真香), I came across an English article about the material.

The author had received a traditional incense formula intended for repelling mosquitoes and clearing a space. It included sandalwood, agarwood, and Jiangzhenxiang.

When he began researching Jiangzhenxiang, however, he found that modern Chinese medicine commonly describes Jiangxiang (降香) as a medicinal material used for things such as stopping bleeding, moving blood, and relieving pain.

That raised a reasonable question:

Why would a material known for stopping bleeding and treating wounds appear in an incense formula meant to be burned?

That question eventually led him into another one: what plant does Jiangzhenxiang actually refer to?

I wrote about that naming history in What Is Jiangzhenxiang? Chinese Incense Material Explained. In short, Jiangzhenxiang and Jiangxiang originally belonged to the same naming tradition, although the material historically came from more than one botanical source. Modern medicinal Jiangxiang was later standardized as the heartwood of Dalbergia odorifera.

But after discussing the subject again recently, I realized that the original question still had another side to it.

Why should we assume that a material valued in medicine must be valued for exactly the same qualities when it is burned as incense?

What does paozhi mean in Chinese incense?

Paozhi (炮制) broadly refers to preparing a raw aromatic material before it enters a blend. Depending on the material, this can involve washing, cutting, simmering, steaming, stir-frying, soaking in tea, alcohol, or honey water, drying, or aging.

The purpose is not simply to make every ingredient smell stronger. It is to make the material suitable for a particular formula and form of burning. Medicinal and incense paozhi can share methods and material knowledge, but their desired outcomes are not automatically identical.

For a wider overview of these methods, see A Map of Paozhi (炮制): Aromatic Material Processing in Traditional Chinese Blended Incense.

The same material does not necessarily serve the same purpose

I brought the question to Xu.

By coincidence, one of the authors of the 2023 paper that helped me untangle the historical identity of Jiangzhenxiang had also been one of Xu’s teachers and had previously advised him on agarwood cultivation.

I told Xu why the English article had initially questioned the material: the author had found old medicinal descriptions of Jiangxiang relating to stopping bleeding and helping wounds heal, and felt that this did not fit the purpose of a burned incense formula.

Xu’s reaction was quite different.

His view is that the traditional medicinal value of Jiangzhenxiang for stopping bleeding and helping wounds heal is closely related to its rich oil content.

Then he added something that immediately interested me:

When we prepare the same material for incense, too much of that oil becomes a problem.

That is where the subject becomes much more interesting.

The same aromatic material can enter two different systems of use, and the qualities we want from it may not be the same.

In medicine, oiliness can be something worth preserving

Xu’s observation is not disconnected from the historical record.

Older materia medica texts repeatedly used oiliness as one way of judging good Jiangxiang. Historical descriptions favored imported material that was reddish with a sweet, non-pungent aroma, or material that was purple and oily. Later quality descriptions also emphasized hardness, a purplish-red color, strong aroma, and an oily texture.

Modern research approaches this from another direction.

Studies of Dalbergia odorifera heartwood identify volatile oils and flavonoids as two important groups of chemically and pharmacologically active constituents.

Modern Chinese pharmacopoeial standards also pay direct attention to this quality. Medicinal Jiangxiang is described as hard and oily, and its volatile-oil content is specifically measured as part of quality control.

A 2023 textual study of Jiangxiang also notes that, once volatile oil was recognized as an important component, modern medicinal processing moved away from heating methods that could cause those volatile constituents to be lost.

So from the medicinal perspective, oiliness is clearly not treated simply as something unwanted that should be removed.

Xu’s own understanding goes one step further: he associates this oiliness with the material’s traditional use for stopping bleeding and helping wounds heal.

I would not turn that observation into a simple modern chemical equation such as “more oil equals stronger hemostatic action.” Traditional experience and modern pharmacology do not always describe materials in the same way.

But placing the two forms of knowledge side by side is useful.

The traditional maker notices the oil.

Historical materia medica valued oiliness.

Modern quality standards and chemical research also pay attention to the volatile fraction.

They are not identical explanations, but they are clearly looking at an important part of the same material.

For incense, too much oil can become a problem

When we prepare Jiangzhenxiang for burning, the direction can be almost the opposite.

The incense material we use belongs to the traditional Hainan context of resinous climbing Dalbergia materials. Research has identified species such as Dalbergia benthamii and Dalbergia pinnata among the materials traditionally used as Jiangzhenxiang there.

For incense making, we first cut the material into smaller pieces and simmer it slowly in clean water.

This usually takes around four to five hours.

As the material heats, oil gradually rises to the surface. We skim it away repeatedly—sometimes three times, sometimes five, depending on the material.

If time allows, Xu may then soak it in green tea or honey water for around a day before drying it again.

Why remove something that may be valued in medicine?

Because when Jiangzhenxiang contains too much oil, burning it directly can produce heavier, harsher smoke.

For incense, we want to reduce part of that oiliness while keeping as much as possible of the material’s own aromatic character: the deep woodiness, slight cooling quality, and the softer sweetness that appears later in the burn.

So the difficult question is not:

How do we remove the oil?

It is:

How much should we remove?

Too little, and the smoke can remain heavy and sharp.

Too much, and the material begins to lose the character that made us want to use it in the first place.

That judgment is part of preparation.

Processing is not simply “cleaning the raw material”

This is why I think the English word processing can sometimes make Chinese incense preparation sound simpler than it really is.

It can suggest ordinary production steps: washing, cutting, drying, grinding.

Traditional aromatic preparation often goes further than that.

The real question is:

What is this material going to be used for?

If the material is being prepared as medicine, certain oils and constituents may be qualities worth preserving.

If the same material is going to be burned directly as incense, some of that oiliness may need to be reduced because of what it does to smoke and combustion.

Neither approach is inherently more correct.

They are preparing the material for different purposes.

In Chinese, there is a useful way to express this idea:

香药同源，不同用

Incense and medicine may share the same source, but they do not necessarily use it in the same way.

This also changed how I read old incense formulas

Returning to the article that started this question:

The author saw a medicinal material associated with stopping bleeding and wound healing inside an incense formula and began to suspect that the plant had been misidentified.

His suspicion eventually led him into a real and complicated historical problem. The names Jiangzhenxiang, Jiangxiang, Shanyougan, and several botanical identities genuinely did become entangled over time.

But looking back, the original mismatch in medicinal function is not, by itself, enough to prove that the incense material was wrong.

It compares what a material was valued for as medicine with the role it might play when burned as incense.

Those can be different roles.

The preparation itself may even move in opposite directions.

That is why identifying a Chinese incense material by its botanical name is only the beginning.

Knowing that something belongs to Dalbergia, or finding its name in an old materia medica, does not yet tell us how it was meant to be used.

The next questions are just as important:

How was it prepared?

And more importantly:

What was it being prepared for?

That is often where Chinese blended incense really begins.

Questions about processing Chinese incense materials

Why are natural incense ingredients processed?

Raw botanical materials do not always burn cleanly or blend harmoniously. Processing can reduce harshness or excess oil, improve combustion, moderate an overpowering quality, and help an ingredient work with the rest of a formula.

Is paozhi the same as making incense?

No. Paozhi prepares individual aromatic materials before they are proportioned and blended. Formulating, grinding, kneading, shaping, drying, and resting the finished incense are later stages.

Does processing remove the natural scent?

It should not erase the material. Skilled preparation adjusts what interferes with the intended use while preserving the aromatic character the maker wants. As the Jiangzhenxiang example shows, removing too little oil can leave heavy smoke, while removing too much can flatten the scent.

Why is Jiangzhenxiang simmered in water?

In Xu’s workshop practice, slow simmering brings excess oil to the surface so it can be skimmed away. The aim is a softer burn with less heavy, harsh smoke while retaining the wood’s deep, cooling, and gently sweet character.

Sources and related reading

• A Map of Paozhi (炮制) — YINN’s overview of aromatic-material preparation methods.
• What Is Jiangzhenxiang (降真香)? — the naming and botanical history behind this material.
• Herbal Textual Research on Dalbergiae Odoriferae Lignum in Traditional Chinese Medicine, 2023.
• Dalbergiae Odoriferae Lignum — Hong Kong Baptist University Medicinal Plant Images Database.