Caffeine is one of the most used substance all over the world. Ideally it should be consumed as less as possible. Find out Fermented Tea vs Herbal Tea caffeine content in the following sections. However Fermented Tea Caffeine levels and Herbal Tea Caffeine levels may differ with their brands, quantity of additives used, types of additives used etc. Below we have given you a generalized idea of safe levels of caffeine in Fermented Tea vs Herbal Tea, their side effects and benefits.