All *real* tea, as in made with tea leaves, has some amount of caffeine, including those labeled "decaf". Decaf teas are allowed a minimal amount by labelling laws, and generally contain about .4% by weight. The general rule is, the darker the tea (which means the longer it's been fermented), the higher the amount of caffeine in the tea. A white tea, such as Harney's Winter White Earl Grey, will have roughly 15mg caffeine per serving, compared to a black tea, which will have roughly 40mg per serving. green & red range in between those two. Decaf tea, which is chemically and mechanically decaffeinated, has about 2mg per serving.
There are herbal 'teas', which contain no tea leaves, that have no caffeine. They're actually tinctures or steeping liquids, but are commonly referred to as teas.
at 5:49 PM on Jan. 10, 2009