Soak almonds in water overnight, changing the water every couple of hours.

Rinse and drain the almonds a couple of times until the water runs clear.

Measure how many cups of almonds you have (they will have increased in size overnight from the soaking)

Place the almonds into a blender or food processor, with water in the ratio of 1 part almonds to 2 parts water (ie if you have 3.5 cups of almonds, you'll need 7 cups of water). Depending on the capacity of your blender/food processor, you may need to do it in batches.

Process/blend for 1-2 minutes until it looks very milky and the almonds are finely ground.

Strain the mixture through cheesecloth or a nut milk bag (available from health food stores).

Store in a covered bottle in the fridge for 4-5 days.