Place the oats, water, and salt (add the dates or syrup at this point, if using) in a blender. Blend on medium or high for 1 ½ minutes.
1 Cup Old Fashioned Oats, 5 Cups Water, ½ Teaspoon Salt
Place a doubled up cheesecloth over the top of a fine mesh strainer and put the strainer over a medium bowl. Pour the oat mixture through the strainer, shaking lightly as needed to get all the liquid through. Based on your preferences, you may want to strain the oat milk more than once.
If adding vanilla, stir it in after straining has been completed.
Store in a covered container or jar for up to 4 days. Shake well before each use.