Alkalizing distilled water is easy. Just add 1/4 tsp potassium bicarbonate per glass to the water to raise the pH from 7.0 to 8.0. It dissolves instantly into the water.
Also this:
Adjusting a cup of Coffee PH
Black Coffee made with distilled water pH 5.0
Black Coffee ¼ tsp Potassium Bicarbonate pH 6.0
Black Coffee ½ tsp Potassium Bicarbonate pH 8.0