Cold brew - ever heard of it? It's becoming a fixture in coffee shops recently, and it should be.
Cold brewing is called such as it makes use of cold water to extract coffee. Components easily dissolve in hot water. So to compensate with the slower dissolution to cold water, you let it contact coffee for a longer time. Well, a much longer time, like 12 hours minimum for most cold brewers!
In this video I made use of the Hario Filter-in Coffee Cold Brewer. I received it as a gift last year, and I'm loving it! Put medium coarse ground coffee in the filter basket, and assemble the bottle. Then just pour the cold water through the mouth before covering with the cap. Then, let it brew for a minimum of 8 hours. I prepared one in the evening and enjoyed cold coffee goodness in the morning!
Cold brew uses more coffee per water to add more flavor. Even with the longer brew time, cold water still couldn't extract some components that hot water could. The advantage of cold over hot brew is that oxidation and degradation occurs much slower. The oxidation of oils leads to coffee tasting sour and degradation of acids adds to the bitter flavor.
Of course, it comes down to your personal preference. I appreciate both for what they are!
Some explanations were based from this article.