Place the oats, water, and ice cubes in a high powered blender. Blend on medium high for one minute. (If your blender can't fit this quantity in one batch, divide it into two batches.)
Strain the oat milk through a fine mesh sieve lined with butter muslin (or a nut milk bag). Let it strain for about 5 minutes, or until it slows to a drip. Then gently ring out the last bit of milk. (Don’t squeeze so hard that the bits of oat will go through the muslin).
Pour the strained oat milk back into the blender, and add the salt and pure maple syrup. Process briefly to mix. (Alternately, you can stir the salt and pure maple syrup into the oat milk once it’s in a jar for storage.)
Transfer the mixture to a large jar. This oat milk will keep in the refrigerator for up to 5 days.
If your blender can't fit this quantity in one batch, divide it into two batches.