In a blender, process all of the ingredients for 15 seconds (do not process longer or the mixture will become gluey).
In a fine sieve, or in a strainer lined with a double layer of cheesecloth, placed over a bowl, strain the mixture. Press down with the back of a ladle to extract the maximum amount of liquid. Set the oats aside and use to prepare the ground oat porridge (see recipe).
Transfer the oat drink into a tightly sealed container. It will keep in the refrigerator for 4 days. Stir before serving.
Note
The maple syrup can be replaced with 1 or 2 chopped Medjool dates.