Caffeine Levels in Tea

Brewed tea has varying levels of caffeine depending on the type of tea. White tea has the least caffeine, green teas and black teas vary greatly, with black tea usually having the highest levels. Within each type, caffeine levels vary depending on the blend, size of the leaves, and brewing time. Bag teas usually have less caffeine than loose teas because of the size and quality of leaves.

Decaffeinated and Herbal Teas

• Decaffeinated tea must have at least 90 percent of the caffeine removed. Most commercial decaf tea contains less than 2 percent of the caffeine of regular black tea. Herbal teas are naturally caffeine free.

General Guidelines

• White, green, and black teas all come from the same tea leaves and contain the same levels of caffeine. Different amounts of caffeine are extracted in the preparation of these teas, however, because of the differences in brewing times and temperatures. According to a Department of Nutritional Services report, a prepared cup of tea contains the following range of caffeine levels:

  Black Tea: 23 - 110 mg
  Oolong Tea: 12 - 55 mg
  Green Tea: 8 - 36 mg
  White Tea: 6 -- 25 mg

  Decaf tea contains 1 to 4 mg and herbal teas contain 0 mg.

  Ounce for ounce, black tea has a little more caffeine than soda, but only about a third of the caffeine of coffee.

Preparation

• Caffeine is extracted more efficiently at higher temperatures. A cup of tea brewed at a lower temperature will have less caffeine than a cup brewed using boiling water. Most of the caffeine is extracted from the leaves during the first minute of steeping. A second brewing will contain significantly less caffeine than the first.

  People who are sensitive to caffeine can brew their tea quickly for 30 to 45 seconds in boiling water, discard the water and brew again for a cup of lower-caffeine tea. This brewing method will reduce the caffeine in tea by up to 75 percent.