Does Soaking and Sprouting Reduce Oxalates?

November 21, 2025 •

5 min read

According to a study on mungbeans, soaking alone reduced oxalate content by over 24%. This and other evidence confirms that soaking and sprouting can significantly reduce oxalates, though their effectiveness varies by food type and other preparation methods.

Quick Summary

Soaking and sprouting can significantly lower oxalate levels, particularly in legumes and seeds, by leaching soluble oxalates and activating enzymes. Effectiveness depends on the food type and process duration. For maximum reduction, combine these methods with cooking and discarding the water.

Key Points

Soaking Leaches Soluble Oxalates: Submerging foods like legumes and grains in water, and then discarding the water, effectively removes a portion of their soluble oxalate content.
Sprouting Uses Enzymes to Degrade Oxalates: The germination process activates enzymes that actively break down oxalates within the food, offering a deeper reduction than soaking alone.
Boiling is a Highly Effective Method for Greens: For leafy greens such as spinach, boiling is the most effective cooking method for reducing oxalates, though it may also reduce water-soluble vitamins.
Combining Methods Maximizes Reduction: For maximum oxalate reduction, combine soaking or sprouting with boiling and discard the water.
Pair High-Oxalate Foods with Calcium: Consuming calcium with high-oxalate foods can bind the oxalates in your gut, preventing their absorption.
Individual Needs Vary: For most healthy people, reducing oxalate intake is not necessary; the benefits are primarily for individuals with sensitivities like a history of kidney stones.
Practice Safe Sprouting at Home: To avoid bacterial risks when sprouting at home, use clean equipment and follow proper rinsing and draining protocols.

Oxalates, or oxalic acid, are naturally occurring compounds found in many plant-based foods, including vegetables, fruits, nuts, and grains. While harmless for most people, excessive intake can lead to health concerns for those sensitive to them, such as kidney stone formation or mineral absorption issues. Soaking and sprouting are two traditional preparation methods often suggested for reducing these compounds. Understanding how and why these techniques work can empower you to prepare your food in a way that maximizes nutritional benefits and minimizes potential downsides.

How Soaking Reduces Oxalate Content

Soaking is a simple yet effective method for reducing soluble oxalate content. Oxalates are divided into two categories: soluble and insoluble. Soluble oxalates are free and can leach into water, making them easier to remove.

Leaching: The primary mechanism behind soaking's effectiveness is leaching. When foods like beans, grains, or leafy greens are submerged in water, a portion of the water-soluble oxalates dissolves into the liquid. Discarding this water before cooking is a crucial step in removing these compounds.
Duration and Temperature: The efficiency of soaking is influenced by both time and temperature. Soaking beans and legumes overnight is a common practice that can significantly reduce their oxalate content. Using warm water can further enhance the leaching process.
Food Type: The type of food also affects how well soaking works. In a study on legumes, soaking was found to decrease total oxalate levels by up to 51.9% in some cases. However, this method is most effective for water-soluble oxalates, so foods with higher insoluble oxalate content may require additional processing.

How Sprouting Reduces Oxalate Content

Sprouting, or germination, is a process that activates enzymes within the seed, grain, or legume. This metabolic activity leads to the breakdown and transformation of various compounds, including antinutrients like oxalates.

Enzymatic Degradation: Sprouting reactivates the plant's metabolism, releasing enzymes such as oxalate oxidase and oxalate decarboxylase. These enzymes actively degrade oxalic acid into simpler compounds, effectively reducing its overall concentration.
Conversion: The sprouting process can cause a redistribution of oxalates. As observed in one study, while total oxalates in sprouted whole seeds decreased, some of the compound accumulated in the seed coats. This highlights the importance of removing the seed coats for certain foods to achieve maximum oxalate reduction.
Enhanced Effects: Sprouting is often used in combination with soaking, creating a powerful one-two punch against oxalates. The initial soak begins the leaching process, and sprouting continues the degradation internally through enzymatic action. A study on mungbeans showed that germination alone reduced oxalates by 57.8%.

The Synergy of Soaking and Sprouting

Combining soaking and sprouting offers a synergistic effect that maximizes oxalate reduction. The initial soak removes a large portion of soluble oxalates through leaching. The subsequent sprouting process then breaks down the remaining oxalates from the inside, providing a more comprehensive reduction. For example, studies on legumes have shown greater oxalate reduction when soaking is followed by a period of sprouting. However, the most significant reductions are achieved by combining these with cooking, particularly boiling, and discarding the soaking and cooking water.

Comparison of Oxalate Reduction Methods


Method	Primary Mechanism	Effectiveness	Best For	Considerations
Soaking	Leaching of water-soluble oxalates	Moderate to significant, depending on food	Legumes, grains, nuts, some greens	Requires discarding water; time-consuming
Sprouting	Enzymatic degradation	Significant, especially for seeds and legumes	Seeds, grains, legumes	Requires specific conditions; may not be suitable for all foods
Boiling	Extensive leaching due to high temperature	Highly effective, up to 87% reduction in some vegetables	Leafy greens (e.g., spinach, chard)	Can lead to nutrient loss; requires discarding water
Steaming	Less leaching than boiling	Moderate, less effective than boiling	Vegetables, retains more water-soluble vitamins	Lower oxalate reduction compared to boiling
Fermentation	Microbial degradation of oxalates	Very effective, especially over prolonged periods	Grains, legumes, vegetables	Changes flavor profile; can take several days
Adding Calcium	Binding of soluble oxalates into insoluble forms	Effective for reducing absorption	Any high-oxalate meal	Reduces absorption, but oxalates are still present

Practical Application for Everyday Cooking

Legumes and Grains: For foods like lentils, beans, and seeds, begin with an overnight soak. Discard the water, then proceed with cooking or sprouting. If sprouting, rinse the sprouts several times a day. If cooking, boil in fresh water and discard the water afterward.
Leafy Greens: For high-oxalate greens like spinach or swiss chard, boiling is the most effective method for reduction. Blanching the leaves for a few minutes in boiling water and then shocking them in ice water can reduce oxalates while preserving some texture and color.
Nuts and Seeds: Soaking nuts and seeds can help reduce oxalates and other antinutrients. Sprouting is also an option for certain seeds. Be mindful that roasting has shown little to no effect on oxalate levels in some nuts.
Combining with Calcium: Always pair high-oxalate foods with a source of calcium, such as a splash of milk, a sprinkle of cheese, or calcium-set tofu. The calcium binds to the oxalate in your gut, preventing its absorption.

The Bigger Picture: Is Oxalate Reduction Necessary?

While these methods can effectively reduce oxalate content, it's important to consider who benefits most from this effort. For most healthy individuals, oxalates pose no significant threat. Our bodies are equipped to handle them, and the overall health benefits of eating plant-based foods often outweigh the potential risks. The conversation around oxalate reduction is most relevant for those with specific health conditions, such as a history of calcium-oxalate kidney stones, certain gut issues, or mineral absorption problems.

For those who are sensitive, managing oxalate intake doesn't have to mean eliminating nutritious foods entirely. Instead, using preparation techniques like soaking and sprouting, combined with other effective methods like boiling and pairing with calcium, can make high-oxalate foods more tolerable. The key is finding a balance that works for your individual health needs while still enjoying a wide variety of nourishing foods.

Conclusion Soaking and sprouting are demonstrably effective methods for reducing oxalates in foods like legumes, grains, and seeds. Soaking leaches out water-soluble oxalates, while sprouting enzymatically degrades them from within. When combined with other practices like boiling and eating with calcium-rich foods, the reduction can be significant. However, the necessity of these steps is primarily for individuals with specific health sensitivities. For most people, the overall benefits of a nutrient-rich, plant-based diet outweigh concerns about oxalates. By understanding and selectively applying these preparation techniques, individuals can confidently manage their oxalate intake and enjoy a varied, healthy diet.

How to Safely Sprout at Home

Sprouting at home can be done safely by following a few key steps to minimize bacterial risk.

Start with Quality Seeds: Purchase seeds specifically for sprouting from a reputable source to ensure they are free from contaminants.
Sanitize Equipment: Thoroughly wash and sanitize your sprouting vessel and hands before starting the process.
Soak Correctly: Follow the recommended soaking times for your specific seeds, typically 2-12 hours in cool, clean water.
Rinse and Drain Frequently: Rinse and drain the sprouts with fresh water at least 2-4 times per day. Good drainage and air circulation are critical to prevent mold and bacteria growth.
Use Good Storage: Store finished sprouts in the refrigerator for a few days, and always discard any that appear slimy or have a foul odor.

Frequently Asked Questions

Boiling is significantly more effective for reducing oxalates in vegetables like spinach and Swiss chard because it leaches a high percentage of soluble oxalates into the cooking water, which is then discarded.

To effectively reduce oxalates in beans and legumes, it is generally recommended to soak them in water for several hours, ideally overnight, and then discard the soaking water before cooking.

No, studies indicate that roasting and baking are largely ineffective at reducing oxalate content in nuts like almonds and cashews. The oxalates are not easily removed through these dry heat methods.

Sprouting is most effective for reducing oxalates in seeds, grains, and legumes. Its effectiveness varies by food type, and it is less applicable for leafy greens.

Soluble oxalates can easily dissolve in water and are most effectively reduced by soaking and boiling. Insoluble oxalates are bound to minerals and are more difficult to remove through typical preparation methods.

No, cooking high-oxalate foods in liquid like a soup or stew does not remove the oxalates. The compounds will simply leach into the liquid, and you will consume them along with the meal.

Yes, pairing high-oxalate foods with calcium-rich foods like cheese or yogurt can help. The calcium binds with the oxalates in your digestive tract, forming an insoluble compound that is then excreted from the body.

While raw sprouts offer certain nutrients, the process of germination can also promote bacterial growth. Commercially grown sprouts have been linked to bacterial outbreaks, so some health experts advise caution. Proper sanitation is essential for home sprouting.

Yes, fermentation is an effective method for reducing oxalates. The microorganisms involved can degrade oxalates over time, particularly in foods like sourdough bread, which is made from grains.

For most healthy individuals, oxalates are not a major health concern. The body can effectively manage them, and the nutrients in high-oxalate foods are often beneficial. Concerns are highest for those with a history of calcium-oxalate kidney stones or certain inflammatory conditions.