Third Wave Water is a well known one. There is a whole book on the topic (2015, with a new edition supposedly coming soon): https://collectedcoffee.com/produc

Third Wave Water is a well known one. There is a whole book on the topic (2015, with a new edition supposedly coming soon): https://collectedcoffee.com/products/water-for-coffee https://collectedcoffee.com/products/water-for-coffee