I've had coffee a few times that has sat long enough to go cold, and I cannot say that I have ever been a fan. I like it only slightly more than I do coffee that has gone cold, and then been reheated in the microwave oven. I daresay I would go to the irrational extreme of foregoing coffee entirely rather than drinking something that has been reheated in the microwave.
I am, by my own admission, a coffee snob though. You can take the boy out of Vancouver, but you can't entirely take Vancouver out of the boy.
On the other hand, I've had iced coffees that I really liked. I had tried making it in the past by brewing it and then pouring it directly over ice, but I could never get it to come out quite the way I wanted.
Last year I tried my hand at cold-brewing coffee. I filled a French press with cold water and enough ground coffee to make 8-10 cups. After a couple of days I pressed the plunger and poured if off into a pitcher, trying my best to leave the sludge behind in the press. The result was much better than what I had ever got from hot-brewing it onto ice, but still not quite what I was after.
I did some more reading on the subject last week when I took the fancy to try brewing it again, and I learned that I had made a couple of minor blunders on my last attempt. Cold-brewed actually means cold-brewed. By brewing it on the counter, I had left it long enough for bacteria and impurities to grow in it, which likely affected the flavour. Also, if I had filtered it after brewing, it would have been a much cleaner drink.
Last week I tried making it again, but with some changes. First, I used filtered water rather than tap water - though that is probably a needless step since our tap water here is quite good. Secondly, I brewed it in the refrigerator rather than on the counter. Finally, I wrapped the grounds in coffee filters, tied shut with cheese cloth. I let it steep for ~14 hours and then removed the grounds. The result was night and day from my earlier attempts. The coffee was full-flavoured and mildly sweet. I don't think that it was actually sweet, rather it lacked completely in the expected bitter.
One of the guides I read on the process explained that cold-brewing produces coffee with a markedly different character and flavour from hot-brewing because the cold water does not release any of the oils, nor modify the flavour of the coffee through cooking it. All in all, I am quite pleased with the results of this method, and I am eager to find out how my current batch turns out. As an added bonus, since caffeine is water-soluble, letting it steep in the fridge for that long does a thorough job of leeching it from the grounds. This cold-brewed stuff is very high-test.
The farmers' market is very colourful this time of year.