Sometimes I find myself in situations where instant coffee is the only thing available. How hot should the water be when I make it? I'm in Britain, so boil water with an electric kettle. Should I pour just off the boil, or let it wait a bit to cool down?
There's an answer to this question at Seasoned Advice: see What water temperature should be used for instant coffee?
A brief summary, taken from @PatrickSebastien's answer:
- Use water at whatever temperature you like to drink your coffee at, or
- Use water just below boiling, around 95-99 degrees Celsius (~205-210 F).
Other articles like this one from WikiHow also recommend using filtered water that is just off the boil.
See also that same SA answer, and this question, for a discussion and additional context about how instant coffee powder is produced.