Tsao-ko (Black Cardamom) Oil

Tsao-ko oil is steam-distilled from the dried fruit of black cardamom (thảo quả), Amomum tsaoko. The plant is grown under forest canopy above 1,000 m. Its main component is 1,8-cineole, with geranial and other aldehydes, giving a warm, spicy, cool and slightly smoky scent.

In traditional Vietnamese medicine, tsao-ko is used for bloating and indigestion. The oil is used as a food flavouring, in seasonings and in perfumery.

Quick facts

Scientific name

Amomum tsaoko Crevost & Lemarié

Trade name

Black cardamom oil, Tsao-ko oil

Part used

Dried fruit (mainly the seeds)

Method

Steam distillation

Appearance and odour

Pale yellow; warm, spicy, cool, slightly smoky scent

Main components

1,8-Cineole 25–45%; geranial, (E)-2-undecenal, α-terpineol

Storage

Dark glass bottle, tightly closed, in a cool place

What is tsao-ko oil?

Tsao-ko (black cardamom) is a large herbaceous plant in the ginger family. Its fruit is oval, with a reddish-brown, ridged skin. Inside are many small, fragrant seeds.

The fruit is dried and used as a spice. It is the same “tsao-ko pod” that goes into a pot of Vietnamese phở broth. Distilling the crushed dried fruit gives a pale yellow oil with a warm, spicy, cool and slightly smoky scent.

Part of the smoky note comes from the traditional way of drying the fruit over a wood fire. Tsao-ko oil is much less common than many other oils.

The raw material only grows in high mountains, with one harvest a year. Most of the dried fruit is also sold as a spice, and only part of it goes to distillation.

What does the tsao-ko plant look like, and where does it grow?

Tsao-ko grows 2–3 m tall in clumps, with long leaves like a large ginger plant. Its flowers and fruit grow right at the base, close to the ground.

It is usually grown at about 1,000–1,500 m, where the climate is cool and moist. The plant needs shade under forest canopy and humus-rich soil along streams. One clump can bear fruit for many years.

The largest growing area is the former Lao Cai province (about 12,500 ha, mostly in Bat Xat, Sa Pa and Van Ban). Other areas include Mu Cang Chai (Lao Cai, formerly Yen Bai province) and Lai Chau (mostly in Phong Tho). Vi Xuyen tsao-ko (Tuyen Quang, formerly Ha Giang province) has a geographical indication.

In Lao Cai, tsao-ko is usually harvested from late July to about October. The classic reference by Do Tat Loi records October to December. Ripening time varies with altitude and from year to year.

Tsao-ko in the Vietnamese kitchen

Tsao-ko is one of the “trio” of spices behind the aroma of beef phở broth, together with star anise and cinnamon. Cooks usually roast the pods until fragrant, crack them, then drop them into the stock.

In the northwest highlands, tsao-ko is also used to marinate smoked buffalo meat, cook the traditional thắng cố stew and flavour rice wine. Its aroma covers gamey smells and adds warmth to winter dishes.

In industry, tsao-ko oil helps phở seasoning packs, concentrated broths and sausages keep a stable flavour from batch to batch. Producers no longer depend on the quality of each lot of dried fruit. These food companies are the main business customers for tsao-ko oil.

Tsao-ko and the forest: a sustainability story

Tsao-ko was once called the “green gold” of the highlands. It helped many Hmong and Dao families escape poverty. But expanding tsao-ko under natural forest, including in special-use forest, has thinned the forest.

Drying tsao-ko with firewood also uses a lot of wood. According to Lao Cai Newspaper, drying 100 kg of fresh fruit needs about 3–4 m³ of firewood.

Lao Cai no longer allows tsao-ko to expand under natural forest. The province aims to phase tsao-ko out of natural forest by 2030. Thao Duoc Xanh gives priority to fruit from production forest and household gardens. The company also encourages improved, wood-saving drying kilns.

Uses

For information only; not a substitute for medical advice.

Applications by industry

Industry	Applications
Food	Phở seasoning flavour, broths, sausages, canned foods
Beverages	Liqueurs, spiced teas
Perfumery	Warm, spicy note; oriental accords
Household	Winter room scents, deodorising storerooms

Why source tsao-ko oil from Vietnam?

Amomum tsaoko grows in a fairly small mountain region, including northern Vietnam and neighbouring parts of China and Laos. For buyers, the Vietnamese supply has some clear points of interest.

• A core growing area: the northern highlands of Vietnam hold large tsao-ko areas, such as about 12,500 ha in the former Lao Cai province.
• Recognised origin: Vi Xuyen tsao-ko has a geographical indication.
• Culinary link: tsao-ko is a signature spice in phở, which helps brands tell an authentic Vietnamese flavour story.
• Traceability: each lot records the buying area, so buyers can see where the fruit came from.
• Sustainability: we prioritise fruit from production forest and household gardens, not from expansion into special-use forest.

Because tsao-ko has one harvest a year, supply is seasonal. Planning ahead is important for larger orders.

Scent profile and blending

Tsao-ko smells warm and spicy, cool from cineole, with a hint of smoke. It immediately brings to mind phở broth and highland kitchens.

• Blend with cinnamon and star anise for a rich spice accord.
• Blend with orange and ginger for candles and winter room scents.
• Blend with patchouli for oriental perfumes.

How to use at home

• Room diffusing: 2–3 drops, blended with cinnamon, star anise and orange.
• Tummy rub for bloating (adults): mix 1 drop with 10 ml carrier oil.
• Scenting a spice cupboard or deodorising a rice store: put a few drops on cotton wool placed nearby. Never drip it directly onto food.

DIY “warm kitchen” sachet

Put into a cloth bag 2 dried tsao-ko pods (cracked), 2 small cinnamon sticks and 3 star anise. Add 3 drops tsao-ko oil and 3 drops orange oil. Hang it in the kitchen or living room on cold days, and add more drops when the scent fades.

How to recognise good oil, and how to store it

• Good oil is pale yellow and clear. It smells warm, spicy and cool, with light smoke, never burnt or sour.
• A very heavy smoky smell may mean the fruit was scorched during drying. Good oil has a balanced scent.
• Keep tightly closed and away from sunlight. Best used within about 2 years.

Tsao-ko, green cardamom and amomum

Criterion	Tsao-ko	Green cardamom	Amomum (sa nhân)
Scientific name	Amomum tsaoko	Elettaria cardamomum	Amomum villosum and related species
Scent	Warm, spicy, smoky	Sweet, floral, cool	Spicy, aromatic, slightly minty
Mostly used in	Phở, savoury dishes	Tea, baking, curry	Digestive remedies, spices

Quality specifications

The main specification is the chromatogram (cineole, geranial). According to Do Tat Loi, tsao-ko fruit contains about 1–1.5% essential oil. Some analyses of the seeds alone give a higher figure. Every lot comes with a COA, an MSDS and a record of the buying area for traceability.

During drying, too much heat can scorch the skin before the seeds are dry, giving the oil a burnt smell. The fruit should be kept whole. Seeds are only removed at distillation time, because shelled seeds lose their aroma quickly.

Reference figures only; actual specifications follow the COA of each lot.

What buyers usually ask for

Tsao-ko oil is mostly bought by food and seasoning companies, which tend to have clear checklists.

• COA and MSDS: every lot has both. Ask for the documents of the specific lot.
• Chromatogram: buyers compare cineole and geranial levels with their reference flavour.
• Origin record: each lot notes the buying area, which supports traceability checks.
• Sustainability: some buyers ask how the fruit was sourced. We prioritise production forest and household gardens.
• Sample before contract: most buyers test a sample in their own recipe first. Contact us to discuss what is available.
• Advance booking: order before the fruit ripens so there is time to collect fruit and schedule distillation.

Growers & cooperatives

The company buys dried tsao-ko fruit in the ripening season, usually late in the year. The exact timing depends on the altitude of each area. Priority areas:

• Lao Cai: Bat Xat, Sa Pa, Van Ban, Mu Cang Chai (formerly Yen Bai province).
• Lai Chau: Phong Tho and other highland districts.
• Tuyen Quang: Vi Xuyen (formerly Ha Giang province).

Requirements and commitments:

• Fruit dried over even heat, dry and crisp, not scorched, not mouldy. Small fruit and second-grade fruit can still be distilled.
• Fruit loses most of its weight when dried. The company buys by kilogram of dried fruit, so pricing is clear.
• Sustainability commitment: priority for fruit from production forest and household gardens. We do not buy fruit from areas expanded into special-use forest.

To sell tsao-ko, call or message on Zalo: +84 983 299 529. See more on the Raw material sourcing page.

Extraction process

1. Sort the fruit and remove mouldy pods; crush.
2. Steam-distil and separate the oil layer.
3. Filter and remove water.
4. Test the oil and keep the COA under the lot number.

Frequently asked questions

Read more: Cassia bark oil Star anise oil Ginger oil Vietnamese herbal essential oils

References: Managing tsao-ko under natural forest (Lao Cai Newspaper) · Geographical indication for Vi Xuyen tsao-ko · Tsao-ko, a crop that brings prosperity (Lao Cai Newspaper)