I know exactly what you mean. I try to get everything in liquid, powder or chewables for the same reason but sometimes you cannot.
You might lose a very miniscule part of your supplement in the grinding that way but as long as you can get as much of the ground powder out and into whatever you plan to mix it in, it should be fine. Make sure that if you take it dry on a spoon, drink something afterwards to help wash it down.
Do not put your ground mixture into a hot liquid or hot food as this can destroy some of its effectiveness.