Weird thing I've stumbled across and I wanna know why?

Ok I may need some verification on this but, I think coffee granules do not dissolve in alcohol (ethanol).

The reason being last night I was going to make myself a nice coffee with a drop of brandy in, but I decided to try a little rum. Now this is special rum called Stroh, it's an Austria cooking rum (used in confectionaries) with a high 80% vol alcohol content - boy I've had some fun getting people to try it neat! Anyway rather than wait for the water to boil and add the rum in last, I put a little in the cup first off (I wanted to make sure I didn't put too much in) added some sugar (dissolved fine) and then the instant coffee granules - which proceeded to just sit and in the solution and not dissolve at all. Then on adding the boiling water the solution in the cup boiled at first (I guess due to ethanol having a boiling pt of about 78 degrees) and then the coffee proceeded to dissolve.

This makes me curious as to the properties of coffee (always wanted to know how instant coffee is made as is nothing like the bean itself). So can anyone enlighten me?