I normally drink instant coffee or use tea bags but occasionally buy filter coffee to use in a machine my Mum left me. Yesterday I opened one of my plastic storage jars with a non airtight lid, and found that it contains about half a bagful of filter coffee that I probably put into it at least a year ago. Is it still safe to use it? How long can you keep it in this kind of container?
Roasted coffee goes stale in a week or two, but once ground it goes stale in as little as 20 minutes. All that surface area isn’t good for long-term storage. As the above answer states, it won’t be dangerous to drink (unless it’s covered in mold) but it won’t taste good.
Personally, I’d throw it out to avoid having to live with the memory of the taste.
