The production of rose black tea is not simply mixing roses with black tea, but using a process called fermentation(窨制), which is a tea making technique that cleverly combines tea leaves with fresh flowers. There are many tiny pores inside tea leaves, which are very easy to absorb water and gas. Mix tea leaves with flowers before they bloom, and the flowers will release a large amount of fragrance when bloom. Through capillary action, tea leaves can absorb the floral fragrance, allowing the tea aroma to blend perfectly with the floral fragrance. This process has very precise control over temperature, time, and humidity, and the steps are cumbersome.