Yes, you can mix soy protein powder with water. Soy protein is a plant-based protein source that is easily soluble in water. The benefits of mixing hemp protein powder with water include convenience and a lower calorie option compared to mixing it with milk. Additionally, water provides a neutral base that does not alter the taste of the soy protein powder, making it a good option for people who want to avoid the taste of milk or who have lactose intolerance.