Explainer 101: What's the deal with oat milk?

As Australia becomes increasingly conscious about health and the environment, more and more milk drinkers are looking to non-dairy alternatives.

A recent CSIRO study showed one in six Australians now opt for plant-based options, with Australia ranking No.1 in the world last year for online searches of the word "vegan".

We've all witnessed the surge in demand for almond milk, then coconut milk, followed by macadamia and cashew milks. But the latest dairy-free milk option that has everyone buzzing is oat milk.

What is oat milk?

Oat milk is a dairy-free, vegan-friendly milk made by soaking and blending oats and water, then straining them through a cheesecloth to separate the milk from the oats.

This milk is then often fortified with additional nutrients such as calcium, potassium, iron, vitamin A and vitamin D, as the "milk" doesn't naturally contain the same nutritional value as oats themselves.

Just because it is a plant-based milk does not mean the switch will automatically result in weight loss.

Bronwen Greenfield, accredited practising dietitian

Why has it become so popular?

Accredited practising dietitian Bronwen Greenfield believes oat milk is a good choice for vegans and people who may be allergic or intolerant to dairy or lactose.

While oat milk has been around since the 1990s, it has recently attracted more interest, with Google Trends tracking a steady increase in searches over the past five years.

The rising popularity of plant-based diets and milk alternatives has no doubt contributed to the uptake of oat milk, but there are several factors that set it apart from other milk alternatives.

Firstly, oat milk is free of many of the allergens found in other types of milk, and contains soluble fibre, which has been proven to benefit heart health.

"The type of fibre present in oats, known as beta-glucan, has been shown to improve cholesterol levels as well as being associated with reduced risk of heart disease," Greenfield says.

"The fibre also provides us with a source of prebiotics, [which] is important for the growth of healthy gut bacteria. Oat milk is also generally a higher protein plant-based milk."

Greenfield says oat milk's creamy and neutral flavour has also made it an increasingly popular choice.

Oat milk also wins out when it comes to sustainability and reducing our environmental footprint.

"While many nut-based milks require a lot of resources to grow and process, oat milk is thought to have less of an environmental impact by requiring less water to grow," Greenfield says.

What's the catch?

When comparing unsweetened oat milk to dairy-based and other plant-based milks, it is clear that oat milk has some drawbacks.

Energy-wise, oat milk contains about 250-290 kilojoules per 100 millilitres, compared to 264 kilojoules for full-cream cow's milk, and a low 60-85 kilojoules for almond milk.

In a world obsessed with low-carb eating, oat milk offers another challenge. It contains a significantly higher amount of carbohydrates compared to other milks, with 12-19 grams of carbohydrates per 100 millilitres, in comparison to 4.8 grams in full cream cow's milk, and only 0.2 grams in almond milk.

"Oat milk tends to have a higher percentage of carbohydrates and fibre when compared with almond, soy or dairy-based milk," Greenfield says.

It also has less protein than soy and dairy milks. It contains 1-2 grams of protein per 100 millilitres, compared to 3.3 grams contained in full cream cow's milk, and 3.5 grams in skim milk.

Greenfield says it is important to recognise that oat milk is not as nutritious as eating oats in their whole form.

"Check that oat milk has been fortified with important minerals and vitamins such as calcium, vitamin D, vitamin A and vitamin B12. Most of our commercial plant-based milk alternatives such as oat milk naturally do not contain much calcium, and require fortification to meet similar levels to cow's milk," she says.

Another drawback to oat milk: it often contains added sugar, as do many other plant-based milks.

"It is important to ensure the milk is 'unsweetened', as many plant-based varieties can come 'sweetened' with added sugar. Also, just because it is a plant-based milk does not mean the switch will automatically result in weight loss. It is actually one of the higher calorie milks with less protein," Greenfield says.

Where to find it

If you're happy consuming a creamy milk-alternative despite the higher carb content, and lower protein and calcium levels, here's the good news: it's super easy to find.

Most cafes now offer oat milk, with Starbucks recently adding the product to its menus worldwide.

Another new brand of oat milk, the Oat Barista Blend plant milk from Califia Farms, has just launched in Australia, after a successful release across the US. The unsweetened blend is made with whole rolled oats, and contains no sugars or gums, promising to be extra creamy and rich to complement coffee without overpowering the taste.

NSW barista Demelza Jones says oat milk has been received well in Australia.

"We're finding more and more customers are requesting oat milk because it's great tasting, incredibly creamy and it has a similar mouth-feel to dairy while being completely lactose free," she says.

"The Australian coffee customer is great at trying and adopting new products into their daily coffee ritual. Customers are enjoying the texture and the taste," Jones adds.