Oat vs Almond vs Soy Milk: Which Plant Milk Is Best?

The plant milk aisle has exploded. Where a decade ago you might have found soy milk and nothing else, today there are dozens of options made from oats, almonds, coconuts, rice, hemp, peas, cashews, and more. They differ dramatically in protein, calories, environmental impact, and how well they perform in coffee. This guide breaks down the real differences so you can choose with confidence.

Nutritional comparison

The following values are for unsweetened, unflavored varieties per 240 ml (1 cup) serving. Exact numbers vary by brand, but these represent typical ranges from USDA data and major brand labels.

Detailed breakdown

Soy milk

The original plant milk and still the nutritional gold standard. At 7g of protein per cup with a complete amino acid profile, soy milk is the only plant milk that nutritionally matches cow's milk. It has a neutral, slightly beany flavor that works in both sweet and savory applications. Fortified soy milk matches or exceeds cow's milk in calcium, vitamin D, and vitamin B12.

Best for: Everyday drinking, cereal, smoothies, baking, cooking (bechamel, soups). If you only buy one plant milk, make it soy.

Concerned about soy? Read our Is Soy Bad for You? The Truth About Estrogen, Hormones, and Health article — the science is clear that moderate soy consumption is safe and beneficial.

Oat milk

The darling of coffee shops for good reason. Oat milk has a naturally sweet, creamy taste and froths better than any other plant milk due to its beta-glucan content. The soluble fiber in oats creates a viscous, smooth texture that mimics the mouthfeel of whole milk. However, it's higher in calories and carbohydrates than most other options, and relatively low in protein at 3g per cup.

Best for: Coffee and lattes (superior frothing), cereal, drinking straight. The top choice for barista applications.

Almond milk

The lowest calorie option at just 30 kcal per cup, but also the lowest in protein. Most commercial almond milks contain only 2-3% almonds — the rest is water, stabilizers, and added vitamins. It has a mild, slightly nutty taste that works well as a neutral base. The thin consistency makes it less suitable for frothing.

Best for: Low-calorie smoothies, light cereal, baking (where you need liquid but not creaminess).

Coconut milk (beverage, not canned)

Coconut milk beverage is the diluted version of canned coconut milk. It has a subtle tropical flavor and a slightly creamy texture from its medium-chain triglyceride (MCT) content. Virtually zero protein, so it should not be relied upon as a nutritional substitute for dairy. The saturated fat content is higher than other plant milks.

Best for: Curries, tropical smoothies, overnight oats where you want a coconut flavor. Not ideal for coffee (tends to separate).

Pea milk

The newcomer that deserves more attention. Made from yellow split pea protein isolate, pea milk delivers 8g of protein per cup — matching cow's milk — with a neutral, clean taste. Brands like Ripple have made pea milk creamy and palatable. It froths reasonably well and is nut-free and soy-free, making it ideal for allergy-conscious households.

Best for: Anyone who avoids soy and nuts but needs high protein. Excellent in smoothies and cereal.

Environmental impact

A landmark 2018 study by Poore and Nemecek published in Science compared the environmental footprint of various milks. All plant milks produce significantly fewer greenhouse gas emissions and use less land than cow's milk. But water use varies considerably:

• Almond milk: 371 liters of water per liter of milk. Almonds are notoriously water-intensive, and 80% of the world's supply comes from drought-prone California. This is almond milk's main environmental weakness.
• Rice milk: 270 liters per liter. Rice paddies also require substantial water and produce methane emissions.
• Oat milk: 48 liters per liter. Oats grow in temperate climates with natural rainfall, requiring minimal irrigation. Oat milk's water footprint is remarkably low.
• Soy milk: 28 liters per liter. The lowest water footprint of any major plant milk, and soybeans fix nitrogen in the soil, reducing fertilizer needs.
• Cow's milk (reference): 628 liters per liter, plus 3.2 kg CO2-equivalent greenhouse gas emissions.

Frothing for coffee

Not all plant milks froth equally. The ability to create stable microfoam depends on protein content, fat content, and the presence of emulsifiers or stabilizers. Here's the ranking from extensive barista testing:

1. Oat milk (barista edition): Best overall froth. Creamy, stable microfoam with natural sweetness. Oatly Barista Edition and Minor Figures are industry standards.
2. Soy milk: Good froth, but can curdle in very acidic coffee. Use barista soy milk or add it to the cup before espresso to reduce curdling.
3. Pea milk: Decent froth with good stability. Neutral taste that doesn't compete with coffee flavor.
4. Almond milk (barista edition): Thin foam that dissipates quickly unless using a barista-specific formulation.
5. Coconut milk: Poor frothing. Tends to separate and creates an oily film rather than microfoam.

Fortification: what to check

No plant milk naturally contains the same nutrients as cow's milk, but fortified versions can match or exceed them. When buying plant milk, always check the label for:

• Calcium: Look for at least 120mg per 100ml (equivalent to cow's milk). Most major brands fortify to this level.
• Vitamin D: At least 0.75µg per 100ml. Essential for calcium absorption.
• Vitamin B12: At least 0.38µg per 100ml. Not all brands include this — check carefully.
• Iodine: Rarely fortified in plant milks outside the UK and Scandinavia. This is a gap you may need to address with supplements. See our Vegan Supplements: Which Ones You Actually Need guide.