5.
Pour the liqueur into dark glass bottles and keep out of direct light. Leave to stand in a cool dark place for at least couple of weeks.
1.
*If mixture has crystallized a little, the vodka will break it back down as long is it is still partial liquid. If you allow it to cool too long it will harden too much. If this happens, simply reheat the syrup and add vodka when it's somewhat cooled down but not hard.
2.
The liqueur tastes best when left in a cool dark place for a few months because it gets smoother with age. You may keep it in the fridge or out of it.
3.
It is really important to simmer the water/sugar/coffee mixture for at least 1-2 hours. This alters and deepens the flavor of the sugar and coffee as the sugar actually caramelizes. Also, as the mixture simmers (losing some of the water and caramelizing) a thin syrup, great for the overall consistency of the drink, forms.