How to Reduce Oxalate Content of Almonds for Better Health

Research indicates that almonds contain a significant amount of oxalates, with some sources reporting over 350 mg per 100g, particularly concentrated in the skin. For individuals sensitive to these compounds or at risk for kidney stones, preparing almonds correctly is a vital step to mitigate health concerns and enhance nutrient absorption.

Quick Summary

This guide explains the most effective culinary processes, such as soaking, blanching, and sprouting, to decrease oxalate levels in almonds and improve their nutritional profile.

Key Points

• Soaking: Soaking almonds overnight reduces soluble oxalates by allowing them to leach into the water, with studies showing 40-77% reduction.

• Blanching: This process of briefly boiling and removing the skin is highly effective because almond skins contain the highest concentration of oxalates.

• Sprouting: For the highest reduction of anti-nutrients, including oxalates, sprouting for 24-48 hours leverages the nut's natural enzymes to break down these compounds.

• Pairing with Calcium: Consuming almonds with calcium-rich foods helps bind oxalates in the gut, reducing their absorption.

• Hydration: Drinking plenty of water is essential to flush oxalates from the body and prevent crystal formation in the kidneys.

Why Reducing Almond Oxalates is Important

Oxalates are naturally occurring compounds found in many plants, including almonds. For most people, moderate consumption is not an issue, but for individuals with a history of kidney stones or certain digestive conditions, a high intake can pose health risks. Oxalates can bind with minerals, especially calcium, forming calcium oxalate crystals. In the kidneys, these crystals can accumulate and form painful stones. The skin of the almond contains a higher concentration of oxalates and other anti-nutrients like phytates, which can hinder the absorption of minerals such as calcium, zinc, and magnesium. Reducing the oxalate content is therefore a strategic way to make almonds a more beneficial part of a health-conscious diet.

Method 1: Soaking Almonds

Soaking is one of the simplest and most accessible methods for reducing the soluble oxalate content in almonds. The process works by allowing water-soluble oxalates to leach out into the water.

How to Soak Almonds

1. Measure and Clean: Place your desired amount of raw almonds in a bowl. Rinse them thoroughly under running water.
2. Soak Overnight: Cover the almonds with warm tap water, ensuring they are fully submerged. For every cup of almonds, add about 1 teaspoon of salt. Let them soak for 8 to 12 hours, or overnight.
3. Drain and Rinse: The next morning, drain the soaking water, which now contains a portion of the removed oxalates. Rinse the almonds again with fresh water.
4. Dry if Desired: The soaked almonds will be soft and more buttery-tasting. For a crunchier texture, pat them dry and then dehydrate or roast them at a low temperature.

Studies have shown that overnight soaking can reduce soluble oxalate content by a significant percentage, with one finding a reduction between 40.5% and 76.9%. Soaking also softens the almonds, which some find more palatable, and can make them easier to chew and digest.

Method 2: Blanching Almonds

Blanching is a rapid process that involves a brief boiling period followed by skin removal. This method is highly effective because it targets the skin, where much of the oxalate is concentrated.

How to Blanch Almonds

1. Boil Water: Bring a pot of water to a rolling boil.
2. Add Almonds: Drop the almonds into the boiling water and let them simmer for just one to two minutes.
3. Cool Quickly: Immediately transfer the almonds to a bowl of ice-cold water or rinse them under cold tap water to halt the cooking process and loosen the skins.
4. Peel the Skins: The skins should now slip off easily with a gentle squeeze. You can discard the skins and the blanching water.
5. Dry for Use: Pat the peeled almonds dry with a clean towel. They can then be eaten, used in recipes, or dried further for longer storage.

Blanching removes the primary source of oxalates in almonds—the skin—and has been shown to reduce soluble oxalates effectively, with some studies reporting reductions between 30% and 87% for a 12-minute boiling process.

Method 3: Sprouting Almonds

For the most comprehensive reduction of anti-nutrients, including oxalates, sprouting is a powerful technique. This process activates the seed's own enzymes, which break down anti-nutrients to prepare for growth.

How to Sprout Almonds

1. Initial Soak: Soak raw, unpasteurized almonds overnight in a bowl of distilled water, similar to the soaking method. Discard the water in the morning.
2. Rinse and Drain: Place the soaked and rinsed almonds in a sprouting jar or colander. Rinse them with fresh water and drain well.
3. Repeat: Repeat the rinse-and-drain process two to three times per day. The almonds will begin to sprout a tiny tail after 24 to 48 hours.
4. Dehydrate: Once sprouted, they can be eaten fresh or dehydrated at a low temperature to preserve them for later use.

Sprouting has been shown to induce a reduction of total oxalates in nuts and seeds by more than 60% in some cases. This is a more time-intensive method but offers superior anti-nutrient reduction.

Comparison: Soaking vs. Blanching vs. Sprouting

Feature	Soaking	Blanching	Sprouting
Time Commitment	Overnight (8-12 hours)	Short (under 10 minutes)	Multi-day (24-48+ hours)
Primary Mechanism	Leaching soluble oxalates	Removing high-oxalate skin	Enzymatic breakdown of oxalates
Oxalate Reduction	Significant (40-77% range cited for soaking)	Significant (targets skin, high concentration area)	Very significant (enzymes break down)
Effect on Texture	Softens the nut	Softens, removes skin	Softens, increases digestibility
Nutrient Impact	Preserves most nutrients	Some nutrient loss due to heat	Enhances bioavailability

Additional Strategies for Managing Oxalate Intake

Beyond preparation techniques, several dietary habits can help manage your body's oxalate load.

Pair with Calcium-Rich Foods

Eating almonds alongside calcium-rich foods can help. Calcium can bind to oxalates in the gut before they are absorbed into the bloodstream. Consider pairing treated almonds with a serving of yogurt, cheese, or low-oxalate greens like kale.

Stay Well-Hydrated

Maintaining a high fluid intake helps dilute urine and remove excess oxalates from the body before they can form crystals. Drink plenty of water throughout the day, especially when consuming higher oxalate foods.

Choose Lower-Oxalate Nuts

If you are highly sensitive to oxalates, consider incorporating lower-oxalate nuts into your diet. For instance, macadamia nuts and walnuts contain significantly less oxalate than almonds.

Conclusion: Making the Best Choice for You

Managing the oxalate content in almonds is a straightforward process with multiple effective options. Soaking is an easy, overnight method that significantly reduces soluble oxalates. Blanching is a fast process that removes the high-oxalate skin, providing a substantial reduction and a smoother texture. For maximum benefit, sprouting offers the highest reduction by activating the nut's own enzymes. Your choice of method depends on your time, desired texture, and personal health needs. By combining these preparation techniques with smart dietary choices, you can continue to enjoy the nutritional benefits of almonds while minimizing any potential risks associated with their oxalate content.

To learn more about the chemical properties of nuts and oxalates, see this study on ResearchGate study on oxalate content of nuts.

Frequently Asked Questions

How many oxalates are in raw almonds?

Raw almonds are a high-oxalate nut, with studies reporting levels varying from around 369 mg to over 450 mg per 100g, with much of the content concentrated in the skin.

Which method is the most effective for reducing oxalates in almonds?

Sprouting, which involves an extended soaking and rinsing process, is generally considered the most effective for reducing oxalates by activating natural enzymes. Blanching is also highly effective due to the removal of the high-oxalate skin.

Does soaking remove all the oxalates from almonds?

No, soaking does not remove all oxalates. It primarily leaches out the water-soluble oxalates, leaving some insoluble oxalates behind. It can reduce the soluble oxalate content by a significant percentage, but not 100%.

Is it okay to drink the soaking water from almonds?

No, you should always discard the soaking water. This water contains the oxalates and other anti-nutrients that have been leached out of the almonds. Consuming it would defeat the purpose of soaking.

Are roasted almonds lower in oxalates?

Roasting is less effective at reducing oxalates compared to soaking or boiling because it is a dry-heat method that doesn't allow the soluble oxalates to leach out into water. Some studies show minor anti-nutrient reduction with roasting, but less than with water-based methods.

Is commercially-made almond milk low in oxalates?

Commercially available almond milk is generally considered low in oxalates. The process of making it typically involves soaking and straining, which removes a large portion of the oxalates.

Can blanched almond flour be used as a low-oxalate alternative?

Yes, flour made from blanched almonds is a lower-oxalate option than flour made from whole, unblanched almonds, as the skin has been removed. However, individuals on a strict low-oxalate diet should still consume it in moderation.