There are many factors influencing caffeine levels in tea, including brewing time / temperature, tea grade and tea varietal.
Tisanes or "herbal teas are usually caffeine free. Similarly, teas blended with other ingredients (such as mint green teas or masala chais) will often have lower caffeine levels than unblended teas.
Most studies show that black tea has between 40 and 120 mg caffeine per eight ounce serving. Decaf black tea usually contains about two to ten mg of caffeine.
The information below comes from a very interesting article on tea and caffeine by Bruce Richardson, who has been instrumental in debunking caffeine myths surrounding tea. Each seven-ounce cup of tea was steeped for three minutes.
- Assam Black Tea (FTGFOP Grade) - 86 mg
- Bai Mu Dan / China White Tea - 75 mg
- Chinese Ti Kuan Yin Oolong - 37 mg
- Darjeeling Autumnal (SFTGFOP1 Grade) Darjeeling White Tea - 56 mg
- Indian Green Tea - 59 mg
- Kenyan Green Tea - 58 mg
- Ceylon Black Tea (OP Grade) - 58 mg
Many Snapple Iced Tea varieties contain 42 mg of caffeine per bottle. Snapple flavors with 42 mg of caffeine include:
- Cranberry Twist
- Diet Lemon
- Diet Peach
- Diet Raspberry
- Very Cherry
Here's a listing of caffeine levels in Honest Tea's bottled teas.
Arizona Iced Tea all contain caffeine. Their black teas have 15 mg of caffeine per eight-ounce serving. Their green teas contain 7.5 mg caffeine per serving. Their white teas contain six mg caffeine per serving.
Twelve ounces of Lipton Brisk Lemon Iced Tea contain seven mg of caffeine, while 12 ounces of Nestea Iced Tea contain 26 mg of caffeine.
A teaspoon of generic, instant iced tea mix contains 27 mg of caffeine, while the same quantity of a decaf equivalent contains about one mg of caffeine.