Oat Milk | How It’s Made

If you have ever had a go at making oat milk at home, you might have found some stark differences between your result and the sweet and creamy commercial version. How does oat milk get made at large scale and what makes it so delicious?

As a big fan of oat milk with my cereal, tea, smoothies or baked goods, I have made countless attempts at making it myself. The tutorials seem rather easy; just blend water with oats and voilà! Additionally, you save money, packaging and can get creative with different versions (I once even tried adding a cardamom pod!). Still, every effort is met with a degree of disappointment: the result always tastes, understandably but dishearteningly, like blended oats. But it turns out there’s a good reason why I've been left frustrated on so many occasions. Here are some of the tricks that separate commercial oat milk from the humble home-made varieties.

Plant-based milk now makes up 11% of the European milk market, with oat milk leading sales in the category. (Photo by Scott Olson/Getty Images)

Turning oat groats into rolled oats

Although different producers have different methods, most of them make oat milk from rolled oats - the kind you see in muesli or porridge - as they are notably easier to break up than the whole grain or ‘oat groat’. The groats are cleaned and graded, dehulled, steamed, and rolled into flakes. When the oat husk or bran (the shell of the oat groat) is removed, we are left with the oat base, which contains less insoluble fibre but still holds the macronutrients and soluble fibre (beta-glucans) of the groat.^1,2

Oats and water are mixed and milled together

The first step consists of mixing rolled oats with water, usually at a similar ratio we would use for most homemade recipes (commonly about 1:2.7), and milling them into a soft homogeneous slurry.^1,3 Some manufacturers already buy oat flour (finely ground oats) to make the process quicker, while others may have oat dehullers and steamers within the oat milk processing plant to control the full procedure.⁴

Adding enzymes

This is an essential step, and the one responsible for the big difference in taste between homemade and store-bought oat milk. Different enzymes, such as α-amylase, break down the complex sugars (like starch) found in oats into simpler sugars, such as maltose, in a process called hydrolysis. This is what makes the oat milk sweeter to taste than the oats themselves.⁵

Since oats consists of around 50-60% starch, and this starch acquires a gelatinous texture when blended or heated, enzymes hydrolysing (i.e. breaking down) starch also helps to create a smoother and creamier texture than if you were to simply blend oats with water.^6,7

While the addition of enzymes may seem foreign and potentially uninviting, the addition of enzymes in the production process to break down complex carbohydrates into simpler ones is fairly common in a number of other foods. For example, to create lactose-free milk, the enzyme called lactase is added to break down lactose into glucose and galactose, making it possible for lactose-intolerant people to drink cow’s milk.⁹

Fun fact: Amylases, the enzymes that break down starch into the simpler and sweeter sugar maltose, are also found in our saliva.⁸

Adding ingredients for texture, taste and shelf life

This step of the process involves the addition of ingredients for taste, texture and appearance purposes. The most common added ingredient is vegetable oil, resulting in a creamier beverage - making it particularly important for the manufacturing of barista versions of oat milk! Salt is also a common added ingredient, as it enhances the sweet and natural flavours of the oat milk. Some brands of oat milk add calcium or vitamins in this step, making a fortified and more nutritionally complete plant based beverage. Lastly and optionally - ingredients such as cocoa powder, sugar, vanilla extract, coffee extract or other natural flavours are added.^1,5

What makes barista oat milk different?

Dairy milk foams because of its high protein and fat content. For non-dairy milk alternatives that are used for steaming or frothing, the use of thickeners and gums is common, in addition to vegetable oils, to make up for a naturally lower protein and fat content. These thickeners and gums are added to help the air bubbles adhere to each other - creating a dense foam that is more similar to dairy versions.

Barista versions will also often contain a ‘pH buffer’ (most commonly dipotassium phosphate) to prevent oat milk from curdling and separating when added to coffee. Interestingly, this addition isn’t necessary with dairy milk, as it naturally contains phosphates which already act as buffers to sudden drops in pH.^10,11

Compare the environmental footprints of plant-based milk alternatives

Sterilisation, homogenisation and packaging

The final product is then sterilised with heat treatments, either with UHT or pasteurisation, to increase its shelf life and kill off any bacteria remaining in the mix. The resulting beverage is then mixed at high pressure with a “homogeniser” (essentially a high-pressure, high-speed blender) to ensure that the fat droplets are broken down into smaller and more uniform droplets, giving the milk a creamy and uniform mouthfeel without any ‘clumps’.^1,12 At last, the oat milk is ready to be packaged and shipped!

Why home-made options need to be refrigerated

You might have noticed that there is often an option for non-refrigerated cartons of oat milk on the shelves - something most homemade recipes don’t recommend. The key difference here is that commercial non-refrigerated options have been aseptically packaged in a highly controlled environment and thus can last for months or even years in your pantry.¹³ When you make oat milk at home, unless you live in a sterile laboratory, you will expose it to microorganisms in the environment that can quickly multiply and become harmful. Therefore, it wouldn’t be safe (or pleasant) to drink a glass of homemade oat milk more than a week after you have made it.¹⁴ But then again, the deliciousness and versatility of the drink may prevent it from lasting this long anyway!