Boil water and sugar until dissolved.
Turn off heat.
Slowly add dry instant coffee and continue stirring.
Add a chopped vanilla bean to the vodka, then combine the cooled sugar syrup and coffee solution with the vodka.
Cover tightly and shake vigorously each day for 3 weeks.
Strain and filter.
Its also best to let the sugar mixture cool completely so the vodka won't evaporate when its added.
If you like a smoother feel to the liqueur you can add about 1 teaspoon of glycerine to the finished product.