Chapter 9 covers coffee, tea, maté and spices raw or simply processed: roasted, decaffeinated, crushed, ground. Decaffeinated coffee stays in 0901 — decaffeination is not a preparation.
The trap is the preparation threshold. The moment a product becomes an extract, essence or concentrate — instant coffee, instant tea — it leaves this chapter for 2101. Coffee substitutes containing no coffee also belong to Chapter 21, while a mixture containing coffee stays here. Mixtures of spices remain in 0910 until they become compound preparations.
Every number opens on the lines beneath it, down to the ten-digit classification number.