Add the oats to a large bowl or jug and cover with water. Leave to soak for 15 minutes then drain them through a sieve over a sink and either discard the soaking water or catch it in a container and use it to water your plants.
Rinse the oats very well under running water then add them to a blender with the optional vanilla, dates and salt.
Cover with around 3 cups / 720 mls water then blend until you can't see the oats anymore. In a high powered blender it shouldn't take more than 20 to 30 seconds. Don't blend it for too long as the heat from the blender can make the milk thicken or turn a little slimy.
Check the thickness. It will likely be quite thick like cream consistency. Add enough extra water to get it to the thickness that you like and give it a quick pulse in between additions. If you are using it as a coffee creamer then it's nice left pretty thick. For other things it's better thinner.
Strain the milk 2 or 3 times through a sieve. You can use a nut milk bag if you have one but it isn't necessary. If you use a nut milk bag straining once will be sufficient. Once strained pour into a bottle or jar and keep refrigerated.
Some separation will occur during storage as with all homemade milks so shake well before using. Homemade oat milk will last for 3-4 days in the fridge. If you wish to use steel cut oats, soak them for 1 hour instead of 15 minutes. They do produce a slightly less creamy milk. This milk works really well when added to hot drinks, but please do not try heating it independently with a steam wand or any other method, for instance when making lattes, hot chocolate etc. When heated it becomes very thick, very quickly and ends up unsuitable for use in drinks. This recipe can easily be adjusted to make smaller or larger amounts to suit your usage. Hover over the number of servings in the recipe card and slide the slider to show how much you would like to make. Ingredient quantities will change accordingly. Nutritional information is calculated as a rough guide only, without the optional ingredients, and before straining (because after straining it would be impossible for me to do without laboratory analysis).