All you really need is oats and water to make oat milk. I recommended using organic oats as conventional oats are heavily sprayed with glyphosate. Making this oat milk will save you money and you know exactly what's going in it!
Add all the ingredients in the blender and blend for about 30 seconds. Don't blend too long or it can turn the milk slimy. Pour oat milk in a fine mesh strainer or cheesecloth over a large bowl. If you find your milk gets slimy try to blend and strain twice. This milk will last up to 5 days in the refrigerator. If it smells funny or different, it means it's going bad.