Unlike green tea, black tea undergoes full fermentation, and typically tends to have a longer shelf life. Black tea in bulk tends to last roughly 18 months, while bagged black tea can stay fresh for up to 24 months. When in paper bags, it can last for up to 2 years, whereas when stored in airtight containers, tins or aluminium packaging it can stay preserved for up to 3 years. Make sure to keep it away from moisture, or items like coffee or spices that can permeate and affect the flavour of the tea.