This is a question that gets asked all of the time, do you use water or milk in your protein shake?
There are many different answers and reasons for choosing either water or milk.
One of the main key factors in selecting to use water or milk in your protein shake are your personal goals.
If you are looking at losing weight, gaining muscle or simply aiming to gain weight you may not want some of the extras you get with using milk.
So this is the choice you will have to make when deciding on what to use.
I might start with a few key features of each if you used them and you might see a pattern emerge.