Make a coarse almond paste in the blender, using the blanched and bitter almonds with 1 tbsp water.
Bring to a simmer the sugar and 1 pint of the water. Simmer 5 mins for light sugar syrup.
In a large container stir the milk and remining 2 pints of water with the almond paste. Stand at least 4 hours or overnight. stir Occasionally.
Strain the almond liquid through a cheesecloth or fine sieve. Discard the almonds.
Mix together the almond liquid, sugar syrup, brandy and orange water.
Refrigerate and serve on ice, or use as a mixer.
If you want a thicker, heavier orgeat, reduce the milk and water by one third.