About Betelnut

The betel nut (Areca catechu L.) is native to Malaysia and grows in East Asia and parts of East Africa. The seeds are called ‘Binrouji’ in Japan, and are used as a luxury item in Asia, similar to chewing tobacco. Medicinally, they were used for deworming and improving gastrointestinal function. The seeds are also used to dye reddish beige, gray, and black.

ビンロウ（檳榔）（Areca catechu L.）.A member of the palm family, it can grow to a height of 30 meters in the largest plants.


The seeds are called ‘Binrouji’ and are used in Asia as a luxury item, similar to chewing tobacco.

About betel nut dyeing

In Japan, betel nut dyeing has been practiced since the Nara period (710-794). The betel nut is used as a dye and dyed in colors ranging from grayish cherry, reddish brown to black. The black color is also known as “檳榔子黒”(betel nut black), and is characterized by its reddish black color, which is considered the highest quality color in the montsuki black dyeing process.

Pigment of betel nut dye

The seeds contain “alkaloids,” which are uplifting components similar to nicotine, and “polyphenols,” a type of tannin. In chewing tobacco, saliva turns red when chewed with a small amount of lime, presumably because the “polyphenols” react with alkali and enzymes and turn red. Under acidic conditions, the reddish color decreases, and iron mordanting causes the color to turn black.

dyeing method

Dyeing is done using the mordant dyeing method.
The decoction is then filtered through a cloth and the resulting decoction is used as the dye solution.
When dyeing plant fibers, use bean juice for pre-dyeing. After aluminum mordanting using the pre-dyeing method, the dye is repeated many times to produce a darker color. Aluminum mordant dyeing produces grayish cherry-red to reddish brown, while iron mordant dyeing produces reddish gray or “檳榔子黒”(betel nut black).

Color difference by mordant