Gyokuro Brewing: The 20-Day Shade, L-Theanine Peak and How to Brew It Right
Understand gyokuro's 20-day shading period, why it produces the highest L-theanine concentration of any tea, and how to brew it at low temperature.
Gyokuro's distinctive flavour comes from shading, which concentrates amino acids at the expense of catechins.
Key takeaways
- 20 days is standard; longer shading (called "tana" or "covered" gyokuro) produces higher umami concentration but at a lower yield.
- Gyokuro is brewed with significantly more leaf than sencha — typically 10–15 grams per 200 ml, almost double the amount.
- Steep time: 1.5–2 minutes is standard for the first infusion. Gyokuro is unique among teas in that it is brewed for multiple short infusions — typically 2 to 3 infusions of 30–60 seconds each after the first.
- Soft, filtered water with low mineral content produces the cleanest cup.
- Brew gyokuro at 50–60 °C with 10–15 grams per 200 ml and steep for 1.5–2 minutes for the first infusion, then 30–60 seconds for subsequent infusions.
Gyokuro — literally "jade dew" — is the most labour-intensive and expensive Japanese green tea, and the flavour difference from conventional sencha is significant. The tea plants are shaded from sunlight for approximately 20 days before harvest, using bamboo screens or cloth covers that reduce direct sunlight by 70 to 90 percent. Shading changes the chemistry of the new leaves: chlorophyll rises (giving gyokuro its distinctive deep green colour), theanine rises, and catechins such as epicatechin and epigallocatechin fall. Caffeine rises too, so shaded tea is not a low-caffeine tea.
The result is a tea with an unusually high concentration of L-theanine — the amino acid that produces the savoury umami flavour and the calm, focused feeling often associated with shaded teas. Gyokuro is richer in L-theanine than standard sencha, and the resulting cup is intensely umami, almost brothy, with very little bitterness or astringency.
The principle behind gyokuro brewing
The tea demands low brewing temperatures because the high amino acid concentration makes it extremely susceptible to tannin extraction at higher temperatures — the same compounds that produce the umami at 50 °C produce bitterness at 80 °C. Brewing gyokuro correctly means using water around 50–60 °C, more leaf than you would use for sencha, and a slightly longer steep time.
Leaf, water temperature and contact time interact, so changing one without noting the others tells you very little. Tea also forgives high temperature far less than coffee does: the same leaf that is sweet at 80C can be flatly astringent at 95C. Fix temperature first, then adjust the leaf.
What most changes the result
Shading duration
20 days is standard; longer shading (called "tana" or "covered" gyokuro) produces higher umami concentration but at a lower yield. Some premium gyokuro is shaded for 30 days or more.
Leaf quantity
Gyokuro is brewed with significantly more leaf than sencha — typically 10–15 grams per 200 ml, almost double the amount. The high leaf-to-water ratio is part of what produces the intense umami character.
Brewing temperature
50–60 °C is the standard range. Higher temperatures (above 70 °C) extract more catechins and produce a more astringent cup. Lower temperatures (below 50 °C) produce a thin, under-extracted cup.
Steep time
1.5–2 minutes is standard for the first infusion. Gyokuro is unique among teas in that it is brewed for multiple short infusions — typically 2 to 3 infusions of 30–60 seconds each after the first.
Water
Soft, filtered water with low mineral content produces the cleanest cup. Hard water mutes the umami character and can leave a metallic aftertaste.
A repeatable starting method
- Bring water to a boil, then transfer to a cooling vessel. Allow to cool to 50–60 °C. Using a thermometer is more precise than visual judgement, especially for the first few brews.
- Pre-warm the teapot and cups. Place 10–15 grams of gyokuro leaves in the pot.
- Pour water at 50–60 °C over the leaves and steep for 1.5–2 minutes. Pour into cups, distributing evenly so the strength is the same in each cup.
- For subsequent infusions, use the same water temperature but shorten the steep time: 30–60 seconds for the second infusion, 15–30 seconds for the third. The flavour evolves through the infusions.
- Taste the difference between the first and second infusions. The first tends to be the most umami; subsequent infusions reveal more aromatic and slightly sweeter notes.
Note the leaf weight, the water temperature, the vessel and the length of each steep separately. Tea changes across infusions, so a single averaged impression hides most of what the leaf actually did.
The numbers we use
These are the figures behind our own green tea guidance, and the starting point this article assumes.
| Starting dose | 12 g per litre, so about 3 g for a 250 ml serving |
| Water | 78C. Boil, then let it stand 4 or 5 minutes. It should not be steaming hard. |
| Grind or leaf | Whole leaf — loose leaf, no grinding needed |
| Total time | 2 min |
| Caffeine | About 85 mg per 3 oz (90ml) small bowl of Gyokuro Imperial Shade-Grown Green Tea |
| Acidity | Low, as we position it against the rest of the catalogue |
| Typical notes | Rich Umami Seaweed, Dewy Melon, Sweet Marine Algae |
When it goes wrong
- Bitter and drying — Water too hot, or steeped too long Let the kettle stand longer, and pull the leaf at 2 minutes.
- Tastes of nothing — Not enough leaf Use more leaf rather than a longer steep.
Worth knowing: Caffeine affects everyone differently. If you are pregnant or nursing, sensitive to caffeine, or have been told to limit it, check with your doctor about how much tea is right for you.
Common mistakes
- Using boiling or near-boiling water. The flavour compounds in gyokuro are particularly sensitive to high temperature, and a hot extraction produces a bitter, astringent cup that does not represent the tea.
- Using too little leaf. The high leaf-to-water ratio is part of how gyokuro produces its characteristic intensity. Using sencha quantities produces a thin, under-extracted cup.
- Discarding the leaves after one infusion. Gyokuro's value is in multiple infusions; brewing once and discarding is wasteful.
- Over-steeping the first infusion. The line between umami and bitterness is narrow, and over-steeping even by 30 seconds can shift the balance.
How to choose your next adjustment
Brew gyokuro at 50–60 °C with 10–15 grams per 200 ml and steep for 1.5–2 minutes for the first infusion, then 30–60 seconds for subsequent infusions. The result should be intensely umami, almost savoury, with very little bitterness. If the cup is bitter, the temperature was too high or the steep time too long.
One caveat on caffeine: leaf ratio and steep length move it more than the tea type does. Brewing gongfu-style at six times the usual leaf ratio produces a far larger dose per cup than the category figure implies.
Related on CupCura
- Japanese Shade-Grown Tea
- Gyokuro Imperial Shade-Grown Green Tea
- The tea catalogue
- Water temperature and steep times
Sources
- Sano T, Horie H, Matsunaga A, Hirono Y. Effect of shading intensity on morphological and color traits and on chemical components of new tea (Camellia sinensis L.) shoots under direct covering cultivation. Journal of the Science of Food and Agriculture 2018; 98(15): 5666–5676 — covering raised chlorophyll, theanine and caffeine and lowered epicatechin and epigallocatechin; Suzuki T et al. Tea Research Journal 2010 — L-theanine and chlorophyll in shaded teas.