Cold coffees have been popular in other parts of the world for eons; however in the U.S. they have gained popularity more recently. There are a number of different methods of preparation, each producing a drink with a very distinct flavour combination.
- Iced coffee is nothing more than your regular filtered coffee served over lots of ice. It is brewed stronger than regular hot filtered coffee to make allowance for dilution that occurs when added to heaps of ice. The drink produced tends to be bitter due to the quick and intense extraction by the hot water.
- Cold brewed coffee makes for a much more flavourful drink. In this preparation regular coffee grounds are allowed to steep in cold water for 18 to 24 hours and then strained. The gentle method of brewing produces a drink that is lower in acidity thus naturally sweeter compared to the iced coffee. It is a more flavourful drink that is not watery. Since it is already cold, extreme dilution is unnecessary. So it is served little ice.
- “Japanese iced method” is another way to make iced coffee. It employs chic gadgets like the Chemex or AeroPress, brews the coffee hot but adds ice early in the process. The hot brewed coffee drips, drop by drop over ice cubes already placed in the flask and cools immediately. The flash cooling captures the flavour, and the aroma to create a drink that is low in acidity and full of taste.
Why Japanese Cold Brew is the Best Method
Japanese iced method is by far the best method of iced coffee preparation for several reasons. In order for all the coffee flavours and aromas to be drawn out, a specific temperature (just below boiling point) is essential. While cold water does manage to do a good job if infusion takes place over many hours, it still can’t match the extraction of hot water. Some oils and flavours in coffee grinds need high temperatures to be able to dissolve in water. Cold water brewing leaves those flavours behind in the grinds.
The aroma of coffee brewing is due to it volatility (the ability to turn to gas). This characteristic increases with higher temperatures. When coffee is brewed hot, and immediately chilled the aromas are locked in; before they have had a chance to escape into the air. When you drink the cold coffee the warmth of your mouth release them again, so your drink has a strong aroma that is lost when other methods of making coffee are used.
When coffee grinds are exposed to the air, the flavourful oils in the grinds begin to react with the oxygen in the air and go bad. The longer the grinds are left standing the greater the stale and sour taste in your cup of Joe. Another fact is that oxidation (the chemical reaction) occurs faster at warmer temperatures. With quickly chilling the coffee, the chances of oxidation are minimized.
Misconceptions About Iced Coffee
It is a common misconception that iced coffee uses excessive amounts of coffee grinds. In reality coffee made by the Japanese iced way actually uses only slightly more grounds than making regular hot coffee. There is no need to produce a concentrated drink that will be watered down with ice. The coffee drips onto the ice a drop at a time, which means that the ices does not melt with speed like it would if a whole cup of coffee was poured on it at once. Hence less ice is required to chill the drink and with less ice there is less dilution.