Making proper Kanzuri requires a few essential things: togarashi red chili peppers grown in Niigata, Japan, citrusy yuzu peel, the fermentation agent koji, time and snow.
After the peppers are harvested in the summer, they bathe in water and salt during autumn and are left to sit outside on the winter snow for about 3-4 days during the winter in a process known as yuki sarashi—a popular preservation technique in Northern Japan. It makes the pepper more mild and balanced, bringing out its sweetness. After, the peppers are combined with yuzu rind, salt and koji (the fermentation agent used to make sake), before the mixture aged for around three years. One more months-long round of yuki sarashi and the kanzuri is finished.