What decaffeination method does Peet’s use? December 14, 2021 17:55 Updated We utilize the water process method for all our decaf ground, whole bean and K-cup® coffees. Related articles Does Peet’s use the Swiss Water process? How much caffeine is in Peet’s Decaf coffees? How does the water process work? Are Peet’s K-cups also decaffeinated using the water process method? Is your coffee grown with pesticides?