Does milk cancel out the acidity of coffee? A closer look at the nutrition facts

October 13, 2025 •

4 min read

With an average pH of around 5, black coffee is naturally acidic, a property that can cause discomfort for some sensitive stomachs. This leads many to wonder: does milk cancel out the acidity of coffee? The answer is more nuanced than a simple yes or no; while it doesn't completely neutralize all the acid, adding milk can significantly reduce coffee's acidity through dilution and chemical buffering.

Quick Summary

Adding milk to coffee mitigates its acidity through dilution and buffering, though it does not eliminate it entirely. This can reduce bitterness and may offer relief for individuals with stomach sensitivity, depending on the milk type and personal tolerance.

Key Points

Milk Reduces Acidity: Adding milk mitigates coffee's acidity through dilution and buffering, but does not completely neutralize it.
Neutralizing Mechanisms: The reduction happens because milk has a higher pH than coffee and its proteins can bind to certain acidic compounds.
Milk Type Matters: Lower-fat dairy or alkaline plant-based milks like almond milk may be better for sensitive stomachs, though high-fat dairy can worsen symptoms for some.
Individual Response Varies: The effect of milk is highly personal; those with acid reflux or lactose intolerance may react differently.
Other Acidity Solutions: You can also reduce coffee's acidity by choosing a dark roast, cold brewing, or using paper filters.
Effect on Flavor: By reducing acidity, milk also softens the bitter notes and can highlight sweeter, caramel flavors.

The Science of Coffee Acidity

Coffee's acidity is not necessarily a negative trait. In fact, it is a key component of its flavor profile, contributing to bright, crisp notes in lighter roasts. However, for those with sensitive stomachs, acid reflux, or Gastroesophageal Reflux Disease (GERD), high acidity can cause discomfort, heartburn, and indigestion. Acidity is measured using the pH scale, where a lower number indicates higher acidity. Black coffee typically has a pH of around 5, which is acidic but less so than a citrus juice, for example.

The perception of acidity is also an important factor. What some perceive as a pleasant brightness in a single-origin coffee, others might taste as sourness or sharpness. This perceived acidity is one of the main factors people seek to alter when they add milk or cream to their coffee.

The Neutralizing Effect of Milk

When you add milk to coffee, it primarily reduces acidity in two ways: dilution and chemical buffering. Milk has a pH of around 6, which is more neutral than coffee's pH. Simply mixing a less acidic liquid (milk) with a more acidic one (coffee) raises the overall pH of the beverage, making it less acidic.

Beyond simple dilution, the proteins in milk play a more active role. Research has shown that milk proteins, particularly caseins, can bind to certain acidic compounds in coffee, such as chlorogenic acids (CGAs). This binding process buffers the acid, which may help prevent it from triggering excessive stomach acid production. Therefore, adding milk provides a double benefit: it dilutes the acid and chemically neutralizes some of its effects.

Dairy vs. Plant-Based Milks

Not all milks are created equal when it comes to managing coffee acidity. The choice between dairy and plant-based milks can have a significant impact on both the flavor and the digestive effect of your coffee.

Dairy Milk

Low-fat and Skim Milk: These options can be beneficial for acid-sensitive individuals because they have a lower fat content than whole milk. High-fat foods can sometimes relax the lower esophageal sphincter (LES), potentially worsening acid reflux.
Whole Milk: While still neutralizing, its higher fat content could be a trigger for some people with GERD.

Plant-Based Milks

Almond Milk: Often praised for its alkaline properties, almond milk can help neutralize stomach acid. However, some brands have added sugars which should be avoided if you have acid reflux.
Oat Milk: With a naturally creamy texture and a slightly alkaline nature, oat milk is another good option for those seeking to reduce acidity.
Soy Milk: Another popular alkaline alternative that can help mitigate coffee's acidity.

How Milk Reduces Coffee Acidity

Dilution: Mixing milk with coffee increases the beverage's volume, thereby spreading the acidic compounds over a larger quantity of liquid and raising the overall pH.
Protein Buffering: Milk proteins, especially casein, have a buffering effect by binding to chlorogenic acids in coffee, which can reduce their irritant potential.
Calcium Content: Dairy milk contains calcium, which is known to help neutralize acids and can offer a small additional buffering effect.
Alkaline Properties of Alternatives: Some plant-based milks, such as almond milk, are naturally alkaline and actively work against the acidity of the coffee.

Comparison of Milk Types for Acidity Relief


Milk Type	Impact on Acidity	Fat Content	Digestibility	Flavor Profile
Full-Fat Dairy	Reduces, but high fat can trigger reflux in some.	High	Potentially difficult for lactose intolerance.	Rich, creamy, masks acidity well.
Skim/Low-Fat Dairy	Reduces acidity, better for reflux due to low fat.	Low	Easier for some, still contains lactose.	Less creamy than whole milk, less flavorful.
Almond Milk	Effective neutralizing effect due to alkaline pH.	Low	Generally easy to digest, lactose-free.	Nutty, adds a different flavor dynamic.
Oat Milk	Good for reducing acidity, naturally alkaline.	Low to moderate	Easy to digest for most, lactose-free.	Creamy, mild, sweet flavor, resembles dairy.
Soy Milk	Good for reducing acidity, also alkaline.	Low to moderate	Can cause issues for those with soy allergies.	Beany, distinctive flavor.
Coconut Milk	Reduces acidity, but high in fat.	High	Varies by individual, may trigger reflux.	Distinctly tropical, can overpower coffee flavor.

Beyond Milk: Other Ways to Reduce Coffee Acidity

Adding milk is not the only strategy for managing coffee's acidity. You can also adjust your brewing habits and choose different coffee varieties to achieve a gentler cup.

Choose a Darker Roast: The roasting process burns off some of the coffee beans' acids, so darker roasts are generally less acidic than lighter roasts.
Try Cold Brew: Cold brewing involves steeping coffee grounds in cold water for an extended period, which extracts less acid and results in a smoother, less acidic concentrate.
Use Paper Filters: Paper filters are more effective at trapping acidic oils and other compounds than metal filters, resulting in a cleaner, less acidic brew.
Consider Alkaline Water: Brewing your coffee with alkaline water can help to neutralize some of the acids from the outset.
Add a Pinch of Baking Soda: A very small amount of baking soda (1/16 to 1/4 teaspoon) can act as a powerful neutralizing agent.

The Bottom Line: Does Milk Truly Help?

So, does milk cancel out the acidity of coffee? While it doesn't entirely erase it, adding milk is a proven and effective way to reduce both the actual and perceived acidity of coffee. The calcium and protein in dairy act as buffers, while the higher pH of both dairy and many plant-based milks provides a diluting effect. For many, this makes their morning cup a far more palatable experience, especially for those prone to digestive issues like heartburn.

Ultimately, the effectiveness of adding milk depends on individual sensitivity, the type of milk used, and other brewing factors. For those with severe acid reflux, combining milk with a darker, low-acid coffee or a cold brew might provide the most relief. Always pay attention to your body's response and adjust your coffee-making process accordingly to find the right balance for your taste and digestion.

An excellent resource for further reading on dietary triggers for acid reflux is available through Harvard Health.

Frequently Asked Questions

It can help by reducing acidity, but high-fat milk may worsen symptoms in some individuals. Alkaline plant-based milks are often a safer bet, but it depends on your specific sensitivities.

Low-fat dairy milk or alkaline plant-based options like almond and oat milk are often recommended for minimizing acidity. They have a higher pH and lower fat content compared to full-fat dairy.

Yes, adding milk dilutes the coffee, which can soften bitter notes and change the overall flavor profile, often making it taste smoother and more mellow.

Milk contains proteins like casein that can bind with and buffer coffee acids. In addition, mixing milk, which has a higher pH, with coffee raises the overall pH of the beverage, making it less acidic.

Yes, using a cold brew method, choosing dark roasted beans, or adding a pinch of baking soda or cinnamon are effective alternatives for reducing acidity.

For most people, milk and coffee together are fine and can be gentler than black coffee. However, those with lactose intolerance may experience discomfort, as dairy milk contains lactose.

Cream, especially high-fat cream, can have a similar buffering effect but may be a trigger for acid reflux in some due to its fat content, which can relax the lower esophageal sphincter.