The critical pH below which enamel erosion occurs if 5.5. Bagged fruit teas are generally below this level with some as low as 2.7. Adding a slice of lemon to your tea will also increase the risk of enamel erosion. What makes the situation worse, is that being a hot drink, tea is usually sipped at, rather than drunk down fairly quickly. This means the duration of acid attack is prolonged. Just as the saliva is attempting to neutralise the acid, another sip of the acidic tea is taken.
It would seem that some people are more prone to enamel erosion that others. This is thought to be due to variation in the composition of the saliva of different people. This is turn may be genetically determined.
It is important to see your dentist approximately every 6 months for a check up. They will be able to spot the early signs of enamel erosion. If you are prone to enamel erosion, you will need to limit your intake of acidic foods and drinks quite carefully.
Herbal teas however tend to have a higher pH than fruit teas, so why not try a peppermint or chamomile tea instead!