The Best Plant Milk for Coffee: Oat vs Almond vs Soy vs Cashew

Why your plant milk coffee isn't working

You pour plant milk into your morning coffee and, instead of a smooth, creamy cup, you get little floating flecks. Or the foam collapses before you've sat down. Or the coffee just tastes thin and a bit sad.

You're not doing anything wrong. Different plant milks behave very differently in hot, acidic coffee, and the one you've grabbed might simply be the wrong match for your cup. The good news is that once you understand why it happens, it's easy to fix.

Here's how oat, almond, soy, cashew and hazelnut milk compare in coffee, and how to get café-style results at home.

Why plant milk splits in coffee

Curdling comes down to two things: acidity and heat. Black coffee is more acidic than most plant milks, and that acid acts like a coagulant on the milk's proteins. Heat speeds the process up, so the hotter the drink, the less acid it takes to make the milk split.

Soy milk is the most sensitive. In tests reported by Australian coffee trade magazine BeanScene, cold soy milk curdled once coffee reached a pH of about 4.6, while dairy milk held out until roughly pH 4.1. Light, fruity roasts are usually more acidic, which is why soy splits more often in them.

A 2019 University of Strathclyde study on soy milk in coffee found something useful too: the split is reversible. Cooling the mixture or adding more milk can bring it back together. In practice, that means temperature and ratio matter as much as the milk you choose.

Fat and protein play a part in frothing too. Protein helps build and hold foam, while fat gives a silky texture. Milks low in both, like many almond milks, tend to make thin, short-lived foam.

Oat vs almond vs soy vs cashew: how they compare

For most coffee drinkers, oat milk is the safest all-rounder. Here's how the main options stack up.

Our pick: oat for everyday coffee, cashew when you want extra richness, and an oat-cashew blend for the creamiest flat white you've made at home.

Make barista-style plant milk fresh at home

Shop-bought "barista" plant milks get their foam and stability from added oils, gums and acidity regulators. Making your own lets you control the creaminess with ingredients, not additives.

Milky Plant Plus turns oats, nuts, seeds or grains into fresh plant milk in under three minutes, hot or cold, at the push of a button. Want a richer milk for flat whites? Simply use more oats or cashews per batch. Want a blend? Mix oat and cashew in the same batch for a creamy, café-style result. The machine strains the milk for you, collects the pulp and cleans itself afterwards.

The Watery finishes the job. Plant milk is mostly water, so the water you use shapes the taste. Our countertop purifier uses four-stage reverse osmosis and then remineralises the water, giving you a clean, balanced base for both your coffee and your milk.

Fresh milk, filtered water, your favourite beans: that's the whole recipe for a better cup.

6 tips for smooth, frothy plant milk coffee

1. Milk first, coffee second. Pour the milk into the cup and add the coffee slowly. The milk warms gradually instead of hitting a wall of hot acid.
2. Let the coffee cool for a minute. A slightly cooler cup is far less likely to split, especially with soy.
3. Choose a darker roast. Medium and dark roasts are generally less acidic than light, fruity ones.
4. Don't overheat the milk. Aim for warm, not boiling, around 60 to 65°C. Overheated plant milk loses its sweetness and froths poorly.
5. Make it creamier. A higher ratio of oats or nuts to water gives more body and steadier foam.
6. Shake or froth just before using. Fresh homemade milk naturally settles, so give it a quick shake for an even texture.

Find your perfect cup

There's no single "best" plant milk for coffee, but there is a best one for your cup. Start with oat for everyday drinks, try cashew when you want something richer, and keep soy for darker roasts.

Better still, make it fresh. With homemade plant milk you choose the ingredients, the creaminess and the blend, with nothing extra added.

Ready to upgrade your morning coffee? Discover Milky Plant Plus and The Watery →