National Booch Day, also known as National Kombucha Day, is observed in the United States every January 15. This informal holiday was launched in 2015 by KeVita to celebrate kombucha, a fermented tea drink known for its distinctive taste and purported health benefits. Kombucha is made by fermenting sweetened black or green tea with a culture of symbiotic bacteria and yeast. The drink likely originated in China during the Qin dynasty and later spread to Russia and Europe. On National Booch Day, kombucha brewers and sellers offer promotions such as discounts and "buy one, get one free" deals to encourage consumption. This day should not be confused with World Kombucha Day, celebrated annually on February 21.