Does Red tea age?
Red tea, which is what most of the English-speaking world calls black tea, holds up better in storage than green or yellow, but it is not an ageing tea. A well-kept red tea stays pleasant for one to two years. After that the aroma thins out and what remains is flat sweetness without much definition.
That is a different failure mode from green tea. Red tea rarely goes off in a way that makes it unpleasant. It just stops being interesting, which is worse in practice, because you can drink it for months without noticing.
So the question for red tea is not whether it will spoil. It is how long it stays worth drinking. And the answer depends more on the container than on the tea.
If it ages: store for the long run
The reason red tea keeps as well as it does is that it is fully oxidized. There is very little left for enzymes to work on, so the leaf is stable. What it loses is aroma, and aroma is carried by volatile compounds that leave slowly through any container that is not genuinely airtight.
So the storage problem for red tea is not spoilage, it is leakage. A tin with a loose lid, a paper bag folded over, or a caddy that gets opened several times a day will flatten a red tea within a season.
This is also why vacuum-packed red tea tastes noticeably better than the same tea six weeks after opening, and why buying a kilo of loose red tea is usually a false economy. The tea does not go bad, but by the time you reach the bottom of the bag it is a shadow of what you paid for.
If you do buy in bulk, split it into two or three sealed tins on the day you get it and only open one at a time. It takes five minutes and it is the highest-value thing you can do for a large bag of red tea.
If it does not: drink it
There are two exceptions worth mentioning. Traditional smoked Lapsang Souchong, the version dried over pinewood fire, is one of the few red teas that people deliberately keep, and it holds its character well for several years.
There is also a small but real practice of ageing sun-dried Yunnan red tea, sometimes called shai hong. Because it is sun-dried rather than fully fired, it behaves a little like raw pu-erh and does change over years. It is a niche product, and most red tea sold in the West is not made this way.
Everything else in the category should be treated as a tea with a shelf life. That includes the expensive single-origin red teas, which are often more delicate than the cheap blends precisely because they have more aroma to lose.
A simple smell test
Smell the dry leaf before you decide to keep it. Red tea should smell sweet and malty, sometimes with a fruity or cocoa edge. If it smells like nothing at all, it has already lost what made it worth drinking, and storage will not restore it.
Also check for any damp or sour note. Red tea is dried to a low moisture content and does not usually mould, but a tin kept next to a kettle will pick up steam, and that is the most common way a red tea is ruined at home.
The other thing worth checking is whether the leaf has gone brittle and broken. Red tea is rolled rather than pressed, and a bag that has been moved around a lot ends up full of dust, which brews bitter and flat regardless of how fresh it is.
A starter timeline
For most people the right plan is to buy red tea in 100 to 250 gram lots and finish it within a year. Store it sealed, in the dark, in a cupboard that does not sit above the oven or beside the kettle.
If you want to try ageing, buy sun-dried Yunnan red specifically and treat it like raw pu-erh rather than like black tea. Ordinary red tea will simply get flatter, and there is no version of waiting that makes it better.
A simple habit that works better than any of this: write the purchase date on the bag. Red tea does not announce its decline, and without a date you will not notice that the tin in the back of the cupboard is two years old.