Oolong tea is usually prepared with hot water, but cold-water brewing is an intesting alternative, especially during the hot days of summer.
And cold-water brewing has some advantages - you end up with less caffeine, theine, and catechins for a sweeter, tastier drink that won't cause sleeplessness.
It's very easy to make cold brew tea - just let some tea leaves sit in cold water for about 4 hours. Amost any type of tea can be brewed this way, but you will get the best taste from lighly oxidized oolong teas. However, you can also try it with darker oolongs or even with black tea.
The method is simple, but there are a few things to keep in mind. It's best to give the tea leaves a quick rinse with cool water before letting them steep. This will wash away any impurities and tea dust. Tea can be cold-brewed in almost any container, but glass or ceramic vessels are the best choice to avoid imparting any foreign taste to the tea.
Use about 6 - 8 grams of loose tea leaves for every liter of water (a heaping tablespoon per quart of water). Let the tea steep in the refrigerator for about 4 hours. If it is too strong, simply add water. If it is too weak, add more leaves the next time.
The tea can be left refrigerated for up to 5 days, but if it becomes cloudy or acquires a sticky texture, it has become contimated with bacteria and should be thrown away. Use up any unrefigerated tea within 2 hours.
You will notice that cold-brewing brings out new tastes to familiar teas. Some teas are even improved with cold-brewing.