1) why don't you just cool regularly brewed coffee in the refrigerator (vs brewing it double strong on top of ice)
2) instead of brewing on top of ice, why not on top of cold water
Ultimately it was easy to say that to get the best flavors coffee needs the drastic and quick temperature change. I did a little digging and found this great quote from Peter G back in 2006. Sadly the link to CCC's write up isn't working.
The thing I love about the "Japanese" process is that the coffee is only hot for mere seconds after it brews: it is almost instantly cooled by the melting ice. This allows it to maintain its fragrance and acidity, and prevents the cooked "airpotty" flavor that inevitably results from letting coffee cool more slowly. It seems particularly good at preserving delicate aromatics, using a floral Yirg in this process is postively overwhelming.
Which leads me to ask,
How or why does a quick temperature change rate impact flavor the way it does? Can we all agree that sweetness/fragrance/nuance is preserved with a quick/drastic temp. change rather than a slow one?
I have brewed different versions in these other ways just for the questioners to taste their answers - and surely coffee cooled slowly tasted worst, oldest, even when served on ice.
Thoughts? Scientific explanations?