Which Legumes Are Acidic? Understanding pH Levels

According to numerous food charts, while some foods are distinctly acidic, many commonly consumed legumes, including beans, lentils, and peas, are actually considered mildly acidic to neutral in their raw state. However, their effect on the body's pH, often referred to as 'acid-forming,' can be influenced by preparation methods.

Quick Summary

This article explores the pH values of various legumes, clarifying misconceptions about their acidity. It details which legumes fall into the slightly acidic or near-neutral categories and explains how cooking can alter their pH. The guide also compares different legumes to help individuals understand their dietary impact.

Key Points

• Legumes are not highly acidic intrinsically: Their raw pH is typically in the neutral to slightly acidic range (5.5-7).

• Metabolic effect is key: Many legumes are considered 'acid-forming' in the body (positive PRAL) due to their high protein and phosphorus content, not their raw pH.

• Green beans are an exception: While slightly acidic by pH, green beans have a negative PRAL, meaning they are metabolically alkaline-forming.

• Cooking and processing affect pH: Canned legumes may have pH-adjusting additives, while sprouting can increase alkalinity.

• Balance is crucial: To counteract the acid-forming nature of many legumes, pair them with alkaline-forming foods like vegetables and fruits.

• Proper preparation matters: For some, soaking or cooking legumes thoroughly can improve digestibility and alleviate potential acid reflux symptoms.

• Focus on whole dietary pattern: A balanced diet with a variety of whole foods is more important than focusing on the individual acidity of one food group.

Demystifying the pH of Legumes

The notion that all beans and legumes are highly acidic is a common misconception, often stemming from general diet recommendations that sometimes oversimplify food chemistry. In reality, the pH levels of legumes are more nuanced, typically falling in the slightly acidic to neutral range. The pH scale, which measures acidity and alkalinity, runs from 0 to 14. A pH of 7 is neutral, anything below 7 is acidic, and anything above is alkaline. For most raw legumes, the pH sits between 5.5 and 7, making them far less acidic than many fruits or processed foods.

It's important to differentiate between a food's intrinsic pH and its effect on the body's pH after digestion, known as the potential renal acid load (PRAL). The PRAL value determines whether a food produces an 'acid ash' or an 'alkaline ash' in the body. A positive PRAL indicates an acid-forming food, while a negative PRAL indicates an alkaline-forming food. Most legumes are considered acid-forming due to their high protein and phosphorus content, but this is a metabolic effect, not a measure of their inherent acidity.

Comparing pH and PRAL of Common Legumes

Understanding the distinction between a food's pH and its PRAL is key to interpreting how legumes affect the body. For instance, while most legumes have a pH in the neutral range, many are considered acid-forming (positive PRAL). Green beans are an exception, with a negative PRAL, meaning they have an alkaline effect on the body despite having a neutral to slightly acidic pH.

Here is a list of some common legumes and their approximate pH and PRAL values:

• Lentils: Cooked lentils typically have a pH between 6.3 and 6.8, which is slightly acidic to neutral. Their PRAL value is generally positive, placing them in the acid-forming category.
• Chickpeas (Garbanzo Beans): The pH of chickpea flour has been measured around 6.38 to 6.52, confirming a nearly neutral pH. Like lentils, chickpeas have a positive PRAL value.
• Kidney Beans: Approximate pH values for kidney beans are typically between 5.4 and 6.0. They are also considered acid-forming based on their positive PRAL.
• Soybeans: With a pH range of 6.0 to 6.6, soybeans are neutral to slightly acidic. Some soy products, like fermented tofu, are considered alkaline-promoting due to their processing.
• Green Beans: Interestingly, green beans can be considered alkaline-forming, with a negative PRAL value of -3.3, despite having a pH of 5.6.
• Peas: Green peas generally have a pH of 5.8 to 7.0, with a positive PRAL of 0.3, making them mildly acid-forming.

The Impact of Preparation on Legume Acidity

The way legumes are prepared can significantly influence their final pH and nutritional impact. Soaking and cooking are two methods that can alter a legume's chemical profile. For example, some sources note that while many legumes are considered acid-forming, processes like sprouting can increase their alkalinity. Furthermore, combining legumes with other foods can affect their overall impact on the body's pH balance.

What About Canned Legumes?

Canned legumes often have their pH adjusted for food safety reasons, which can affect their taste and nutritional profile. The processing can slightly change the natural pH. For instance, one reference indicates canned peas can range from pH 5.6 to 6.5. Always check the ingredients list, as some canned beans are processed with added salts or acids that may further alter their pH.

Addressing Digestive Issues and Acidity

For those with digestive sensitivities, such as acid reflux, understanding the acid-forming nature of legumes can be helpful. However, it's crucial to remember that this isn't due to their inherent acidity but rather their metabolic effect. Many individuals who experience digestive issues with legumes find that proper preparation, like soaking or slow cooking, can improve tolerance. The fiber content of legumes is also a significant factor in digestion and can affect different people differently.

Practical Advice for Incorporating Legumes

To balance the acid-forming potential of most legumes, consider pairing them with alkaline-forming foods. A good strategy involves following the 60% alkaline to 40% acid-forming diet guideline. This means complementing your legume-based meals with plenty of green vegetables and some fruits. Here are some easy ways to do this:

1. Lentil and Vegetable Curry: Combine acid-forming lentils with alkaline-forming vegetables like spinach, broccoli, and peppers. The spices and herbs are also typically alkaline.
2. Chickpea and Kale Salad: Mix acid-forming chickpeas with kale, a highly alkaline green, and a lemon-tahini dressing to create a balanced meal.
3. Kidney Bean and Cucumber Salad: Pair kidney beans with fresh cucumbers and bell peppers, both of which are alkaline.
4. Split Pea Soup with Greens: Enhance classic split pea soup with a handful of fresh kale or spinach stirred in at the end for an alkaline boost.
5. Edamame with Sea Vegetables: Enjoy shelled edamame with mineral-rich, alkaline sea vegetables like kelp or dulse.

Legume Acidity vs. Alkaline Ash Formation

Feature	Legume's pH (Intrinsic)	Legume's PRAL (Metabolic)
Definition	A measure of a food's acidity on a 0-14 scale, with 7 being neutral.	A measure of the acid or base residue (ash) left in the body after a food has been digested.
Most Legumes (Raw)	Tend to be slightly acidic to neutral (pH 5.5-7).	Tend to be acid-forming (positive PRAL) due to high protein and phosphorus content.
Example: Green Beans	Slightly acidic (pH 5.6).	Alkaline-forming (negative PRAL -3.3).
Example: Peas	Slightly acidic to neutral (pH 5.8-7).	Mildly acid-forming (positive PRAL 0.3).
Influencing Factors	Can be slightly altered by cooking or canning processes.	Influenced by a food's mineral content, particularly protein and phosphorus.
Primary Relevance	Food processing and preservation.	Dietary impact on the body's metabolic balance.

Conclusion

In summary, while the question of which legumes are acidic reveals that they are not inherently highly acidic, they can have an acid-forming effect on the body due to their nutritional composition. The pH of raw legumes like lentils, chickpeas, and beans is typically in the slightly acidic to neutral range. However, their high protein and phosphorus content contribute to a positive PRAL, meaning they leave an acid-forming residue after digestion. For those concerned with their diet's acid-alkaline balance, the key is not to eliminate legumes but to pair them with plenty of alkaline-forming vegetables, fruits, and herbs. This approach ensures a balanced, nutrient-dense diet that supports overall health without sacrificing the many benefits legumes offer, such as protein, fiber, and essential minerals.

Sources:

• Acidic and Alkaline Food Chart - Soul Food Shonali. (2021). [Online]. Available at: https://www.soulfoodshonali.com/blog/the-acid-alkaline-debate/ [Accessed 17 Oct. 2025].
• The Alkaline Diet: An Evidence-Based Review - Healthline. (2023). [Online]. Available at: https://www.healthline.com/nutrition/the-alkaline-diet-myth [Accessed 17 Oct. 2025].

Additional Considerations for Legume Acidity

For those interested in optimizing their diet based on acid-alkaline balance, a deeper understanding of the PRAL concept is essential. It's not the food's taste or raw pH but its mineral and protein composition that matters most for metabolic effects. For example, while citrus fruits taste acidic, they are metabolically alkaline-forming. Similarly, legumes are metabolically acid-forming, which can be balanced by consuming alkaline counterparts. The focus should be on a holistic dietary pattern rather than eliminating entire food groups. A balanced diet rich in whole foods, including a variety of fruits, vegetables, grains, and legumes, is generally recommended for good health.

Note: This article is for informational purposes only and does not constitute medical advice. Consult a healthcare professional for dietary recommendations.

Frequently Asked Questions

What is the pH level of chickpeas?

Chickpea flour has a near-neutral pH, typically measured around 6.38 to 6.52. However, metabolically, chickpeas are considered acid-forming due to their protein and mineral composition.

Are lentils acidic or alkaline?

Cooked lentils have a pH of 6.3 to 6.8, which is slightly acidic to neutral. After digestion, they are considered acid-forming due to their positive PRAL value.

Do canned beans have a different pH than dried beans?

Yes, canned beans can have a different pH than dried beans due to the canning process and the addition of salts or other additives for preservation. The final pH is often adjusted to ensure food safety.

Can I eat legumes if I have acid reflux?

Some people with acid reflux may experience symptoms from legumes due to their metabolic acid-forming effect. However, proper preparation, such as soaking and slow cooking, can improve digestibility. Pairing them with alkaline foods and consuming in moderation is often recommended.

Which legumes are considered alkaline-forming?

While most legumes are metabolically acid-forming, green beans are an exception and are considered alkaline-forming with a negative PRAL value. Some soy products, especially fermented ones like miso and tempeh, are also alkaline-promoting.

What is the difference between a food's pH and its PRAL?

A food's pH is its direct measure of acidity or alkalinity on the 0-14 scale, while PRAL (Potential Renal Acid Load) measures the acid or alkaline residue left in the body after metabolism. A food can have a neutral pH but be metabolically acid-forming.

Does soaking legumes change their acidity?

Soaking legumes primarily serves to reduce their content of antinutrients like phytic acid, which can improve digestibility. While it may slightly affect the final pH, its main benefit is related to how the body processes the food, rather than a significant change in its intrinsic acidity.