Suppose I brew a 16 oz cup of coffee, take just one generous sip (one ounce), and then put the rest in the fridge.

Just how "stale" is my coffee, when I revisit it 24 hours later?

  • 4
    Why do you think caffeine will go? Correct me if I'm wrong, but it'll be stale because the flavour's gone, not the caffeine. Oct 26, 2015 at 5:12

1 Answer 1


Caffeine does not break down (at any appreciable rate) when left alone in a drink. It requires the enzymes in your body to break it down, so when you take the drink out of the fridge, it'll be just as caffeinated as when you put it in.

However, your drink will still be stale, because there are plenty of other organic compounds in the coffee that will break down over that time, affecting the taste. Also, assuming you reheat the coffee, the reheating will have further effects, making it taste very bitter.

Either make yourself a smaller coffee (16oz is a lot!) or drink it all when it's fresh.

  • 5
    There are many bacteria out there that metabolize caffeine, so theoretically once colonized, it could lose some, but at that point, you shouldn't be drinking the coffee anyways, you should be studying it under a microscope. Oct 26, 2015 at 19:12

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