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Cis-3-Hexenol in Tea: The Science of 'Fresh Cut Grass'

By TeaTrade Science Team • Updated January 2026 • Reading Time: 8 Minutes

There is a specific smell that defines Japanese Green Tea. It is sharp, verdant, and instantly recognizable: the smell of a freshly mowed lawn. To Western palates, this can be shocking. To a tea master, it is the smell of freshness.

The molecule responsible is Cis-3-Hexenol, colloquially known as "Leaf Alcohol." It is a volatile compound produced by almost all green plants when they are damaged, acting as a distress signal. But in tea, it is carefully preserved through the steaming process to create the signature "Green" profile of Sencha and Matcha.

In this deep dive, we explore the Lipoxygenase pathway that creates this molecule, why Japanese tea has 50x more of it than Chinese tea, and why the Yabukita cultivar is the undisputed king of green.

Molecular structure of Cis-3-Hexenol overlaid on fresh Japanese tea leaves.

Molecule Profile: Cis-3-Hexenol

Chemical Class: Unsaturated Fatty Alcohol
Formula: C6H12O
Aroma Profile: Fresh Cut Grass, Green Apple, Leafy
Boiling Point: 156°C (Highly Volatile)
Key Cultivar: Yabukita (Japan)

Key Takeaways

1. Biosynthesis: The Lipoxygenase (LOX) Pathway

Unlike Linalool or Geraniol which are stored as glycosides, Leaf Alcohol is produced de novo (from scratch) the moment the leaf is plucked.
The precursor is Linolenic Acid (a fatty acid in the cell membrane). When the leaf is damaged during harvesting, an enzyme called Lipoxygenase (LOX) attacks the fatty acids, breaking them down into 6-carbon aldehydes and alcohols.
This rapid enzymatic burst creates the intense "Green Smell" that fills a tea factory during the spring harvest.

2. Steaming vs. Pan-Firing: The Fate of the Molecule

Once Cis-3-Hexenol is created, the tea maker has a choice: keep it or kill it. This decision defines the difference between Japanese and Chinese Green Tea.

Method Process Effect on Cis-3-Hexenol Flavor Result
Steaming (Japan) High steam blast for 30-60s Preserved. Steam locks the leaf pores shut and deactivates oxidases without volatizing the heavy alcohols. Vegetal, Grassy, Marine (Sencha)
Pan-Firing (China) Hot metal wok contact Destroyed. Direct conductive heat evaporates the volatile Leaf Alcohol. Nutty, Toasted, Chestnut (Longjing)

Expert Tip: The "Covered Aroma" (Ooika)

In shaded teas like Gyokuro, the lack of sunlight alters the lipid metabolism. Instead of pure Cis-3-Hexenol, the plant produces huge amounts of Dimethyl Sulfide (reminiscent of corn or seaweed) alongside the Leaf Alcohol. This combination creates the unique "Nori-like" aroma known as Ooika.

If you drink Japanese tea, you are drinking Cis-3-Hexenol. Why? Because 75% of all tea fields in Japan are planted with one cultivar: Yabukita.

Yabukita was selected in the 1950s specifically for its "refreshing aroma." Genetic analysis shows it has an unusually high potential for converting fatty acids into Cis-3-Hexenol.
Other cultivars like Sayamakaori produce even more, creating a sharp, almost aggressive bitterness and green snap. In contrast, Saemidori (a cross of Yabukita x Asatsuyu) is lower in Leaf Alcohol and higher in Amino Acids, making it sweeter.

4. Brewing: Managing the Green

Cis-3-Hexenol is highly volatile (boiling point 156°C) but easily detectable even at low temperatures.
The Water Temp: If you brew Sencha with boiling water (100°C), you will extract excessive Catechins (bitterness) alongside the Leaf Alcohol, creating a soup that tastes like boiled spinach.
The Sweet Spot: Use 70°C - 80°C water. This temperature is hot enough to volatilize the Cis-3-Hexenol (giving you the fresh aroma) but cool enough to keep the bitter tannins in check, allowing the L-Theanine sweetness to shine through.

Taste the Freshness

Want to experience the purest expression of Leaf Alcohol? Try a Deep-Steamed (Fukamushi) Sencha from Shizuoka.

Best Sencha Teas

Read Next: The Chemistry Cluster

Understand the other molecules that define your cup.

The Umami

L-Theanine Guide
The savory amino acid that balances the green.

The Process

Kill-Green (Fixation)
How heat stops the enzyme clock.

The Plant

Yabukita Cultivar
The genetic master of Japanese flavor.

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