What's in Your Tea
茶的自然成分
Pure water, and a leaf. A remarkably simple beverage — and yet one of the most compositionally interesting things you can put in a cup. Here is what high-quality loose-leaf tea actually contains.
A transparent look at the leaf
Nothing added. Nothing hidden.
Only what the mountain gave.
Premium loose-leaf tea is one of the most transparent products you can buy: a single dried plant, processed with heat and craftsmanship, brewed with water. No ingredients list requiring a dictionary. No preservatives extending shelf life at the cost of flavour. No sugar masking the natural character of the leaf.
At Yunshan we source teas whose growing conditions — altitude, geology, seasonal timing, and the patience of the grower — produce leaves naturally rich in the compounds that define fine tea: polyphenols, amino acids, trace minerals, and volatile aromatics. What follows is a plain account of what those compounds are.
Eight things naturally present in fine tea
Natural purity
Sugar-Free
Properly brewed loose-leaf tea contains no sugars whatsoever — not added, not residual. Pure water and leaf produce a beverage whose subtle sweetness comes entirely from amino acids and volatiles, not carbohydrates.
A standard 200ml gongfu infusion: 0g sugar · 0g fat · 0–2 kcal
What you see is what you brew
Additive-Free
Single-origin loose-leaf tea contains one ingredient: the dried leaf of Camellia sinensis. No preservatives, no artificial colouring, no flavour enhancers, no binding agents, no anti-caking compounds. What is in the tin is what goes in the cup.
Yunshan teas contain no added ingredients of any kind
Naturally occurring plant compounds
Tea Polyphenols
Tea polyphenols are a family of naturally occurring compounds found in the leaf, including catechins (such as EGCG), theaflavins, and thearubigins. Their concentration varies by tea type, altitude, harvest season, and processing method.
Green teas: 15–30% polyphenols by dry weight · Oolongs: 8–20% · Black: 4–12%
Unique to the tea plant
L-Theanine
L-theanine is a non-protein amino acid found almost exclusively in Camellia sinensis. It accounts for up to 50% of the free amino acids in high-grade tea. Shade-grown teas such as gyokuro and matcha are notably rich in it; slow-growing high-altitude teas also accumulate higher concentrations.
Shade-grown teas: 30–50mg per cup · Standard greens: 15–25mg · Black teas: 5–10mg
Absorbed from mountain terroir
Minerals
Tea leaves accumulate minerals from the soil in which they grow. The mineral profile of a cup of tea reflects its terroir — the particular geology, altitude, and hydrology of the garden. High-mountain gardens tend to produce mineral-rich infusions with a distinctive mouthfeel.
Potassium · Manganese · Fluoride · Zinc · Copper · Magnesium
Paired with L-theanine in the leaf
Natural Caffeine
Tea naturally contains caffeine — produced by the plant as a deterrent to insects. Unlike supplemental or extracted caffeine, the caffeine in tea is present alongside L-theanine in the same leaf. Content varies significantly: young spring buds contain more caffeine than mature leaves; higher growing altitudes increase concentration.
Green teas: 20–45mg per cup · Oolongs: 30–55mg · White teas: 15–30mg
Present in the fresh leaf
Vitamins
Fresh tea leaves contain various vitamins, though processing and infusion affect what remains in the cup. Minimally processed teas — such as white tea and first-flush greens — retain higher levels. Vitamin C is present in some green teas; the B-vitamin group (B1, B2, B3) occurs across most types.
Vitamin C (green/white) · B1 Thiamine · B2 Riboflavin · B3 Niacin · Vitamin K
When prepared without additions
Zero Calories
Plain brewed tea — without milk, sugar, or other additions — contains effectively zero calories. The dissolved compounds that give tea its flavour, aroma, and colour are present in trace quantities. Tea is among the most calorie-neutral beverages that exists outside of water.
Per 200ml plain infusion: 0–2 kcal · 0g fat · 0g carbohydrate · 0g protein
Deep Dive
Tea polyphenols — a family of naturally occurring compounds
Polyphenols are a large category of naturally occurring compounds produced by plants — primarily as a response to UV light, insects, and pathogens. In the tea plant, Camellia sinensis, they accumulate in the leaf and account for 15–30% of the dry weight of unoxidised (green) teas.
Processing transforms them: oxidation converts catechins into theaflavins and thearubigins, which give black teas their colour and body. Microbial fermentation in aged pu-erh further changes the polyphenol profile into complex polymeric forms not found in fresh-leaf teas.
This means the type and concentration of polyphenols in your cup is a direct expression of processing method — which is why origin-traceable, single-lot tea has a genuinely different compositional fingerprint from blended commercial tea bags.
Polyphenol concentration is influenced by:
- Growing altitude and UV exposure
- Soil nitrogen and mineral content
- Harvest timing (spring vs. autumn)
- Degree of oxidation in processing
- Age and storage conditions (for pu-erh)
Catechins
儿茶素类
Green & White Tea
The most abundant polyphenol group in unoxidised tea. The four main catechins are EC, ECG, EGC, and EGCG — with EGCG being the most studied and highest in concentration in high-grade green teas.
Theaflavins
茶黄素
Black Tea
Formed when catechins oxidise during the production of black tea. Theaflavins give black tea its golden-red colour and are found in concentrated form in high-quality Assam and Keemun varieties.
Thearubigins
茶红素
Black & Pu-erh Tea
Complex polymeric compounds formed during extended oxidation or microbial fermentation. They contribute to the deep mahogany colour and full body of aged pu-erh and black teas.
Flavonols
黄酮醇
All Tea Types
Including quercetin, kaempferol, and myricetin. Naturally present across all tea types, with higher concentrations found in first-flush and shade-grown varieties.
Gallic Acid
没食子酸
Oolong & Black Tea
A simple phenolic acid naturally occurring in tea alongside other polyphenols. Present in higher quantities in more heavily processed teas.
A transparent look at the leaf
Nothing added. Nothing hidden.
Only what the mountain gave.
Premium loose-leaf tea is one of the most transparent products you can buy: a single dried plant, processed with heat and craftsmanship, brewed with water. No ingredients list requiring a dictionary. No preservatives extending shelf life at the cost of flavour. No sugar masking the natural character of the leaf.
At Yunshan we source teas whose growing conditions — altitude, geology, seasonal timing, and the patience of the grower — produce leaves naturally rich in the compounds that define fine tea: polyphenols, amino acids, trace minerals, and volatile aromatics. What follows is a plain account of what those compounds are.
40–50 mg / cup
Gyokuro (shade-grown)
40–50 mg / cup
Gyokuro (shade-grown)
40–50 mg / cup
Gyokuro (shade-grown)