A tablespoon is a non-scientific but very widely used unit of volume, which works very well in cooking, herbal medicine, etc. It is represented by a capacity of one tablespoon which varies from roughly 15 mL in the US to 20 mL in Australia.
1 If tea is properly stored, it can potentially last up to a year for green and black teas. White tea lasts about six months before it isn't as good in quality as when fresher. Stale tea (or bad tea) will taste flat, as if you're drinking paper.  Glass or ceramic containers are fine provided that they're opaque.
Store Coffee in an Airtight Container. One of the most frequently asked questions we get at Peetâs is about coffee storage. We recommend that you keep a weekâs worth of coffee in an airtight, opaque container at room temperature to protect it against the staling effects of heat, light, and moisture. Whole beans will keep up to four weeks, but ground coffee should be brewed within a week or two.