Caffeine is one of the most used substance all over the world. Ideally it should be consumed as less as possible. Find out Earl Grey Tea vs Spearmint Tea caffeine content in the following sections. However Earl Grey Tea Caffeine levels and Spearmint 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 Earl Grey Tea vs Spearmint Tea, their side effects and benefits.