What is a chasen ?
A chasen is a traditional tea whisk for making matcha.
Also known as a bamboo whisk in English, a chasen is a beautiful and intricate tool carved out of a single piece of bamboo into fine strands or 'tines'. Its use is only for whisking powdered matcha with hot water. The quality of your finished drink depends largely on the quality of your chasen. A metal whisk or battery powered whisker simply ruins the quality of your matcha.
The number of tines is important as this is responsible for producing different kinds of foam. The most common number of tines are 70, 80, 100 and 120, with 70 and 120 being less common. A 120-tine chasen is an incredible work of art as the tines are simply so thin. One wonders how they were even carved by hand. A 120-tine chasen is normally reserved for particular tea ceremonies.
Also important for creating the perfect foam is the kind of bamboo used. One of the most well-known chasen crafting families with a 500-year old history, hunts bamboo based on the desired use, and the volume of foam trying to be achieve. Some tea ceremony schools whisk a very thin island of foam in the middle of the bowl of matcha, whereas others, Chiki Tea charistas included, aim for a voluminous foam with almost whipped egg white consistency.
For high quality chasen, the bamboo is hunted, then washed, sun-dried, and left to age for 3 or even 6 years so the chasen won't warp or break easily. The longer the aging process, the darker the bamboo becomes. One length of bamboo normally yields only three or four whisks. This is because the joint of the whisk must be placed with precision accuracy, allowing 9 centimeters of bamboo above it for carving, and 3 centimeters below it for the handle. The joint is below the tines and helps line up the fingertips. Chasen that are mass produced in other countries, offered at cheap prices, do not go to this level of attention therefore they will not last long or be as beautifully crafted.
To the layman, a chasen has three main parts: the handle, the bloom (outer) and the heart (inner). After thinly shaving the outer layer of the bamboo to prepare it for the main cutting, the section just above the joint is split into 16 equal sections. Each split section is about 4 millimeters wide; then the inner part of each strip is carved out, leaving a tine about 1 millimeter thick. Each of these tines is then further split into 10 tines. This creates 160 tines with 80 for the outer bloom and 80 for the inner heart. In this example, this would be considered an 80-tine chasen.
In order to create the bloom and heart, a piece of special string is woven between the tines to separate them. The string can be any color but the most common is black. Tea ceremony schools will request a particular color such a bright red, purple or even a mix of colors like blue and white combined. The final step is for the craftsman to twist the tines of the inner heart to create a rounded peak in the middle. As beautiful as this is, the curled edges are not meant to last.
A new chasen will lose the delicate curls on the ends of the tines. This is supposed to happen! Relaxing the tines in hot water before whisking is mandatory before each use as it protects the tines from breaking off. By the second or third use, you will no longer see the curled tips.
To most, a chasen looks incredibly precious but in the early days of tea ceremony, often performed by samurai, the chasen was a disposable item, similar to our plastic forks or chopsticks. Nowadays, the chasen has a much longer life and is often used by a tea ceremony teacher to inspect a student's level of whisking ability, focusing on broken tines. The chasen should not touch the bowl during the vigorous whisking motion which is where tines often break or wear thin.
A beginner can aim to use a chasen for about 4 weeks of regular whisking while attempting to perfect the motions. A professional will likely achieve 3 to 6 months use before a replacement is required. Of course this depends on how many times per day or week it is used as well as how it is cleaned and stored.