This simple little video put out by best value carpet store shows you how to remove coffee stains from one of their carpet tiles. First of all it's important to note that the lady in video is working with a brand new piece of carpet with full carpet stain resistance. Stain resistance on brand new carpet will pretty much stop anything from becoming a stain in the carpet. All that is really needed to remove a coffee stain from carpet like this is a towel. No cleaning solution is needed because the coffee never penetrates the carpet fiber. If this piece of carpet was 3 years old or older it would be worn from foot traffic and soil build up. The stain resistance would be greatly impaired if not completely removed. Coffee would easily enter the dye sites of the carpet and change it's color. That would be a much more difficult spill to remove.
With any spill on the carpet, coffee or otherwise, it's always best to move quickly to remove the substance before it changes the carpets appearance. Here are some quick steps to ensure you remove coffee spills as soon as they happen.
How to remove coffee stains from carpet:
If you can get to it right away you should be able to remove the coffee quite easily. If the spot dries with some discoloration it might be time to bring in a professional carpet cleaner.