The Kouridashi Iced Tea Method

May 3, 2021

Water quality, temperature, and length of steeping are all factors that influence the flavor profile of a cup of tea. These are details we typically keep in mind when preparing a hot cup of tea. But did you know that these factors affect the flavor of iced tea just as much? How to best brew a batch of iced tea has long been a subject of debate amongst tea connoisseurs, but a lesser known cold brew technique from Japan has been receiving high praises for creating high quality tea liquor. It’s called Kouridashi.

One common method of making iced tea in North Carolina (and much of “the South” in the United States) is brewing the tea hot and refrigerating the resulting liquor. While admittedly one of the easiest and most efficient ways to brew iced tea, brewing a big batch of tea in boiling water then cooling it down can result in bitter flavors — and if you’re brewing a green or a white tea, it can completely burn away the base flavor of the tea! People brewing bitter, astringent iced tea is part of the reason “sweet tea” became so popular. Sugar was used to hide the burnt flavors.

Another popular iced tea technique is cold brewing. Cold brewing tea avoids astringency and results in a fuller flavor. Typically, this method involves steeping the tea in cold water for 6 to 12 hours in the refrigerator. This allows for the flavor to be slowly extracted from the tea leaves. Thanks to the absence of heat, the tea comes out smooth and refreshing. This method of cold brewing tea is also popular in Japan, where it is known as Mizudashi (literal translation: extracted with water). 

In western countries we typically think of there are four flavors: sweet, salty, sour, and bitter. Japan has a fifth flavor known as umami. Umami can be described as a “mellow savory taste.” Adjectives such as brothy, intense, and meaty have been used to describe the concept of umami.

In an attempt to extract the umami flavors from the tea, a second cold brewing technique was developed in Japan. Kouridashi involves the use of ice instead of water. As you might expect, the Kouri in Kouridashi means ice. This process involves acquiring fine tea leaves (usually white or green) and putting them in a cup over large ice cubes. Because this method is typically reserved for high-quality teas, a cup or Kyusu teapot is used to prepare the tea rather than a larger pot or pitcher. This allows the flavor to be distributed fully and evenly. With Kouridashi, long hours in the refrigerator isn’t necessary. Once the ice begins to melt, the cup of iced tea can take as little as 30-40 minutes or as long as 2 hours. 

To achieve peak umami flavor, it is important to first select a high quality tea for Kouridashi. Teas that are known to be suitable for Kouridashi-style brewing include sencha, gyokuro, and Yi Zhen Bai Hao (Silver Needle). However, experimenting beyond the Kouridashi staple teas can result in successful brews as well! The Kouridashi brewing method can bring out new flavor profiles in your favorite tea. Once your tea is selected, the magic happens.

After the tea is placed into the bottom of the container (about two teaspoons), the ice is gently placed over the top. Preferably, the ice is at least the size of cubes from a standard ice cube tray. Large ice molds meant for glasses of whiskey are perfect for Kouridashi. Pouring water on top of the speed up the melting process has become common in recent years. If using hot water to speed up the process, it is not recommended to introduce water at a temperature greater than 90°F to green tea. Many Kouridashi tutorials advise the use of hot water, but depending on the tea (and your level of patience), it’s not always the wisest option. Even with ice present, you still run the risk of burning your tea leaves.

Traditionalists of the Kouridashi technique recommend letting the ice melt at a natural pace. According to these traditionalists, peak umami flavor is achieved if the ice is allowed to melt slowly inside of a clay Kyusu teapot. The longer the time in which the tea steeps, the bolder the flavor of the resulting liquor. Many tea enthusiasts swear by the Kouridashi method. It is a great way to make delicious iced tea during the summer! And Kyusu teapots are both reliable and beautiful if you plan to level up your Kouridashi with appropriate tea accessories.