Proper tea storage seems to be a problem which has not been paid enough attention.
I have experimented a little and found out that jasmine tea is particularly vulnerable to changes in aroma and flavour: oxygen seems to be the worst enemy. Unfortunately, I am a little addicted to a certain aroma- and flavour-related aspect of some jasmine teas, and it is this very aspect that tends to get lost quite soon upon improper storage.
As for tea I have purchased from Seven Cups, the coated bags you use seem to be one of the best options for efficient preservation of the original aroma and flavour. (And your teas really have it right when I purchase them!) However, these bags have just one little minus: when I re-close the bag, I have to be extra careful and check that the bag is really closed indeed, otherwise the tea would go bad. Of course I can do (and am doing) that but I am interested in keeping my everyday tea in a more solid container, especially one with a more solid closing mechanism, so that I won't have to worry about whether I closed the container properly or not. For longer-term storage I find these bags to be the best option indeed.
I have experimented only with jasmine teas as I do not drink other teas very much. In a non-airtight container, a good jasmine tea will obtain an excessively sweet aroma (unwanted, although some people may even like it) or a specific extraneous scent (unwanted) just in days.
I also experimented with a stainless-steel container closed airtight with a silicon-sealed lid (the lid itself is unfortunately made of transparent plastic, so I had to cover it to prevent exposure to light - but it is still plastic). Even with this container it seems that tea somehow loses some of its original aroma in a matter of days (even though in such a container, tea does not obtain any unwanted aroma -- just loses a little of the original). Maybe it is the plastic lid that does this? I suspect that stainless steel could be guilty too.
Hence, I have found out that the usual metal tea boxes (non-airtight) sold everywhere are out of question for jasmine tea (and probably for other teas). Anything other non-airtight is very bad. Any rubber sealings are bad too (only silicon sealings seem to be OK). Wood seems to be bad. Plastic seems to be bad. Any other porous material seems to be bad.
Glass is reported to be bad because letting light in. (But otherwise the best tea I can buy locally in my country has been kept in a glass jar not exposed to light, with a silicon sealing and a stainless-steel lid, and this tea definitely has the right aroma and flavour when I buy it.)
This has led me to the conclusion that glazed ceramics (plus silicon sealings) may be one of the best options for storing jasmine tea. Another good option seems to be glass+silicon (and possibly stainless steel lid) if kept away from light. Opaque glass (airtight with a silicon lid) could be even the most efficient method but I have not seen such containers anywhere. Coated bags (as also used by Seven Cups) seem another great option but they have the minus I mentioned above.
I have not finished my search yet, therefore, I thought that it could be most welcome if Seven Cups could share the expert experience about various options for properly storing delicate teas (especially jasmine tea) -- maybe in a video or here at the forum.
