If measured by its dry weight, tea DOES have a higher caffeine count than coffee.
However, we largely don’t eat tea leaves or coffee beans directly (though chocolate-covered espresso beans are amazing).
The brewing of tea uses less of the dry-leaf-tea-product per 8 oz cup than dry-coffee-product required for brewing the same 8 oz size cup of coffee, and therefore generally has less caffeine per cup.
In fact, the amount of time that tea (or coffee for that matter) brews affects the amount of caffeine in the cup of tea made. Caffeine is extracted over time, and the longer tea is steeped the higher the concentration of caffeine per cup.
It is this fact that has led to the confusion around different types of teas having different caffeine content.
Yes, drinking less oxidized versions of tea (green, white etc) will generally have less caffeine than more oxidized versions of tea (black, oolong). However this is not because of the tea type's inherent or process-derived properties, but because less oxidized teas are steeped for shorter periods of time at lower temperatures whereas more oxidized teas are steeped longer at higher temperatures, thus allowing more caffeine to be extracted from the leaf to the liquid.
Further complicating these guidelines are other variables that affect caffeine content in both the unprocessed tea leaf and the brewed cup of tea. Caffeine content can be increased in a brewed cup if the tea leaves are broken. A good example of this being the “tea fannings" used in tea bags. The same tea leaves steeped whole will produce less caffeine in a brewed cup than the smaller pieces often found in bagged tea.
The unprocessed leaf can also contain varying amounts of caffeine, with greater amounts being in the new growth on the plant—these leaves are often picked for high quality white teas.
Growing method and location have also been known to affect the caffeine in the tea plant: soil chemistry, altitude, variety of tea plant (Camellia sinesis v Camellia assamica). The list of variables continues.
decaffeinated It would seem that buying decaffeinated teas would allow you to sip your favorite beverage without the added kick of caffeine—but those seeking a truly caffeine free experience should not rely on this sometimes misunderstood classification. In this process most of the caffeine is removed, but a small amount will still remain.
pre-steep home-decaffeination Another disputed home-decaffeination process is a quick pre-steep of your tea. Many individuals (and tea companies) have put forth the theory that most of the caffeine of an initial steep will be absorbed in the first infusion of your tea, and that dumping this first cup will allow one to make subsequent infusions with the used leaves that yield a caffeine free drink. Caffeine is released over time, and this method may only remove a quarter of the caffeine from the leaves, unfortunately many of the tea's antioxidants and health benefits are dumped along with the caffeine in that first cup.
herbal infusions The best way to ensure you are not ingesting caffeine is to swap out your Camellia sinensis (or Camellia assamica) tea for an herbal infusion (often called a tisane). Botanicals such as chamomile, mint, and lavender contain no caffeine but do yield infusions with wonderful bouquets and flavors. They can be infused on their own or with other botanicals for a more complex cup.
rooibos (or redbush) tea bonus - another caffeine free alternative One popular botanical that has been used as tea alternative is rooibos tea. This South African tea has found its way into the hearts of tea lovers everywhere looking for a full-bodied experience without caffeine. It is velvety and mildly sweet and mixes well with botanicals and flavorings to offer an array of interesting rooibos variations.
