Oat milk is not acidic. It sits right around neutral on the pH scale, with commercial products ranging from 6.26 to 7.72 and averaging about 7.0. For reference, pure water has a pH of 7.0, and anything below 7 is acidic. So most oat milk lands in a narrow band from very slightly acidic to slightly alkaline, depending on the brand and its ingredients.
How Oat Milk Compares to Other Milks
A Swiss analysis of commercial plant-based beverages and cow’s milk measured pH across multiple brands of each type. Oat milk samples came in at 6.8 to 7.4, which is slightly higher (less acidic) than cow’s milk, which consistently measured at 6.6. Almond milk ranged from 6.7 to 7.5, and soy milk ranged from 6.6 to 8.0. Rice milk had the highest pH of all, close to 8.0.
The takeaway: none of these milks are meaningfully acidic. They all cluster near neutral, with plant-based options tending to be equal to or slightly more alkaline than cow’s milk. If you’re choosing between them based on acidity alone, the differences are too small to matter for most purposes.
Why the pH Varies Between Brands
Oat milk is made by blending oats with water, then using enzymes to break down the starch into simpler sugars. This is what gives oat milk its natural sweetness without adding sugar. The enzymes work best at specific pH levels, and manufacturers adjust conditions during production to optimize the process. Some formulations call for a mildly acidic environment (around pH 4.5) during one enzymatic step and a near-neutral environment (around pH 6.5) during another.
After processing, added ingredients shift the final pH. Calcium carbonate, a common fortifier, is alkaline and nudges the pH upward. Stabilizers like dipotassium phosphate, found in many barista-style oat milks, also act as pH buffers. This is why a study of 37 commercial oat milk products in Thailand found such a wide spread, from 6.26 to 7.72, even though they’re all made from the same base ingredient.
Oat Milk and Tooth Enamel
Tooth enamel starts to dissolve at a pH below about 5.5. Since oat milk sits well above that threshold, it poses very little erosion risk on its own. Researchers reviewing the dental data have concluded that under normal consumption conditions, oat milk is unlikely to contribute to enamel erosion.
That said, oat milk does carry a higher cavity risk than cow’s milk for a different reason: sugar type. The enzymatic process that breaks down oat starch produces glucose and maltose, which mouth bacteria ferment into acid more readily than the lactose found in cow’s milk. Cow’s milk also contains calcium and proteins that help buffer acid and protect enamel, a protective effect that plant-based milks largely lack. So while the drink itself isn’t acidic, sweetened or sugar-rich oat milks can still promote acid production inside your mouth after you drink them.
Acid-Forming vs. Alkaline-Forming After Digestion
Some people asking whether oat milk is acidic are really asking about its effect on the body after digestion. This is measured using a score called PRAL (potential renal acid load), which estimates whether a food leaves behind acid-forming or alkaline-forming byproducts when metabolized. A negative score means alkaline-forming, and a positive score means acid-forming.
Oat milk averages a PRAL of about -0.79, making it mildly alkaline-forming. Individual products ranged from -2.34 to +0.97, so most oat milks are neutral to slightly alkaline in their metabolic effect. For comparison, fruits and vegetables tend to be strongly alkaline-forming, while meat and cheese are acid-forming. Oat milk falls in between, close to neutral on both sides of the equation.
Why Oat Milk Curdles in Coffee
If oat milk isn’t acidic, why does it sometimes curdle when you pour it into coffee? The answer is that coffee is acidic, typically sitting between pH 4.5 and 6. When the proteins in oat milk hit that acidic environment, they lose their structure and clump together. The temperature of the coffee accelerates this reaction.
A few tricks reduce curdling. Barista-edition oat milks contain stabilizers and buffering agents specifically designed to hold the emulsion together in hot, acidic liquids. If you’re using regular oat milk, warming it before adding it to coffee helps by reducing the temperature shock. Adding a tiny pinch of baking soda to your coffee neutralizes some of its acidity without noticeably changing the flavor. You can also try pouring the coffee into the oat milk rather than the other way around, which exposes the milk to the acid more gradually.