This is part of our Milk Alternatives Complete Guide. See also Oatly vs Califia and Oat Milk vs Almond Milk.
How Homemade Oat Milk Is Made
Making oat milk at home is straightforward. The basic process involves blending rolled oats with water (typically a ratio of 1 cup oats to 3–4 cups water), then straining the mixture through a cheesecloth or fine mesh bag to remove the oat solids. The result is a thin, milky liquid. Some recipes add a pinch of salt, a date for sweetness, or a small amount of oil for creaminess.Nutritional Comparison
This is where homemade oat milk has some notable differences from the commercial versions. Commercial oat milk like Oatly uses an enzymatic process to break down oat starches into smaller sugars, which creates the slightly sweet flavour and smooth texture the product is known for. This process also affects the glycaemic response — commercial oat milk can raise blood sugar more readily than you might expect from an oat-based product.Homemade oat milk made by simple blending and straining does not go through this enzymatic process. As a result it retains more of the oat fibre, has a different (slightly starchier) texture, and may have a lower glycaemic impact. However it also tends to be thicker, less smooth, and can separate more quickly in the fridge.
On calories, homemade oat milk made from 1 cup of oats and 4 cups of water yields approximately 130–150 calories per cup depending on how much oat material passes through the strainer — broadly comparable to commercial oat milk.
Fortification: A Key Advantage of Store Bought
This is the most significant nutritional advantage of commercial oat milk over homemade. Most commercial oat milks are fortified with calcium, vitamin D, and B12 — nutrients that are difficult to obtain in adequate amounts from a plant-based diet. Homemade oat milk contains none of these added nutrients unless you specifically add them yourself.If you drink oat milk as a dairy substitute and rely on it for calcium and vitamin D, homemade oat milk will not provide those nutrients. For people who already get adequate calcium, vitamin D, and B12 from other dietary sources this matters less, but it is an important consideration for vegans or people with limited dietary variety.
Ingredients and Additives
Homemade oat milk has a clear advantage in ingredient simplicity — it contains just oats and water with no added oils, stabilisers, emulsifiers, or preservatives. Commercial oat milks typically contain added rapeseed or sunflower oil (for creaminess), dipotassium phosphate (an acidity regulator), and various fortification additives. None of these are harmful, but if clean ingredients are important to you, homemade is the simpler option.Cost
Homemade oat milk is considerably cheaper than commercial versions. A litre of commercial oat milk typically costs £1.50–£2.50 depending on brand and retailer. A litre of homemade oat milk costs approximately 20–40 pence in oats. The cost saving is significant for regular users — over a month of daily use the saving can be £20–£40 or more.Which Should You Choose?
Choose store bought if: you want consistent texture and frothing performance in coffee, rely on the fortified calcium and vitamin D, or value convenience over cost savings.Choose homemade if: you want to reduce packaging waste, save money, prefer minimal ingredients, get calcium and vitamin D from other sources, and do not mind the slightly different texture and shorter shelf life.
Use our Daily Calorie Needs Calculator to find your daily calorie targets and our Food Tracker to log your intake.