How long do you need to soak oats to remove phytic acid? Your guide to better nutrition

October 21, 2025 •

4 min read

According to scientific studies, soaking grains like oats can significantly reduce phytic acid, a compound that hinders mineral absorption. Learning exactly how long do you need to soak oats to remove phytic acid? can help unlock the full nutritional potential of this healthy breakfast staple, ensuring you get the most out of every bite.

Quick Summary

Soaking oats reduces phytic acid, enhancing nutrient absorption and digestion. Methods like overnight soaking, with or without an acidic boost, can effectively break down this mineral-binding compound.

Key Points

Overnight Soak: Aim for at least 8-12 hours of soaking at room temperature to initiate phytic acid breakdown.
Add an Acidic Medium: Accelerate phytic acid reduction by including 1 tablespoon of apple cider vinegar, lemon juice, or cultured yogurt per cup of oats during the soak.
Enhance with Phytase-Rich Grains: Incorporating a small amount of freshly ground rye or buckwheat flour provides the phytase enzyme that oats lack for more effective phytate neutralization.
Improves Mineral Absorption: The primary benefit of soaking is increasing the bioavailability of minerals like iron, zinc, and calcium, which are otherwise bound by phytic acid.
Boosts Digestion and Texture: Soaking helps to break down starches, leading to easier digestion and a creamier, softer final texture.
Consider Your Dietary Needs: Soaking is most beneficial for individuals with sensitive digestion or for those who consume large quantities of whole grains.

Understanding Phytic Acid in Oats

Phytic acid, also known as phytate, is a natural compound found in the outer layers, or bran, of many plant seeds, nuts, and whole grains. In plants, it serves as a storage form of phosphorus. When humans consume foods containing phytic acid, it can bind with important minerals in the digestive tract, such as calcium, magnesium, iron, and zinc, forming complexes called phytates. Our bodies lack the necessary enzymes to break down these phytates, which can limit the absorption of these essential minerals.

While this has earned phytic acid the reputation of an "anti-nutrient," it's important to recognize that it also possesses potential health benefits, including antioxidant properties. The potential issue arises when diets are heavily reliant on unsoaked whole grains or when an individual already faces mineral deficiencies. Therefore, preparing foods in a way that minimizes phytate content is a traditional and effective strategy for maximizing nutrient bioavailability.

How Long Do You Need to Soak Oats to Remove Phytic Acid?

For significant phytic acid reduction, the general recommendation for soaking oats is at least 8 to 12 hours, or overnight. However, simply soaking in water is often not enough to achieve maximum reduction, as oats contain a relatively low amount of the enzyme phytase, which is required to break down phytic acid. For more effective and consistent results, incorporating an acidic medium or a phytase-rich grain is recommended.

Methods for Maximum Phytic Acid Reduction

Method 1: Soaking with an Acidic Medium
- Duration: 8 to 24 hours.
- Process: Combine your oats with warm water and an acidic substance like apple cider vinegar, lemon juice, or a cultured dairy product such as yogurt or kefir. A common ratio is 1 tablespoon of acid per cup of oats.
- Benefit: The acidity helps create an environment conducive to breaking down phytates, even in oats with low natural phytase content. Soaking at room temperature, rather than in the fridge, can further enhance enzyme activity.
Method 2: Soaking with a High-Phytase Grain
- Duration: 12 to 24 hours.
- Process: For the most effective reduction, soak oats with a small amount of a freshly ground grain known to be rich in phytase, such as rye or buckwheat. The phytase from the added grain will help neutralize the phytic acid in the oats.
- Benefit: This method mimics traditional grain preparation techniques and can achieve very low phytate levels.

Step-by-Step Guide for Soaking Oats

Select Your Oats: Rolled oats and steel-cut oats are excellent choices for soaking. Raw oats might require a slightly shorter soak (6-8 hours) to prevent them from becoming rancid.
Choose Your Liquid: Water is the most common liquid, but you can also use milk or dairy-free alternatives.
Add Your Acid (Optional but Recommended): Mix in 1 tablespoon of an acidic medium like lemon juice or yogurt per cup of oats for enhanced phytic acid breakdown.
Combine and Soak: Place the oats, liquid, and acid into a glass jar or bowl. Ensure the oats are completely covered. For maximum effectiveness, leave the mixture to soak at room temperature for 8 to 12 hours.
Rinse or Cook: After soaking, you can choose to rinse the oats to remove any excess starch and potentially improve the texture. You can then cook them into porridge or use them raw for overnight oats. Cooking after soaking also contributes to further phytic acid reduction.

The Difference Soaking Makes: A Comparison


Feature	Unsoaked Oats	Properly Soaked Oats
Phytic Acid Levels	High, potentially inhibiting mineral absorption.	Significantly reduced, increasing mineral bioavailability.
Nutrient Absorption	Limited, as phytic acid binds to minerals like iron and zinc.	Enhanced absorption of vital minerals, maximizing nutritional benefit.
Digestibility	Can be harder to digest for some individuals due to complex starches.	Starches are partially broken down, making them easier on the digestive system.
Preparation Time	Quick cooking time (for rolled oats), but requires heating.	Requires advance preparation (overnight), but ready to eat without cooking.
Texture	Firm, chewy texture when cooked.	Creamier, softer, and more pudding-like consistency, even when uncooked.
Flavor	Nutty, but can have a slightly bland or grainy taste.	Slightly tangy or richer flavor, depending on the soaking medium.

Beyond Soaking: Other Methods for Reducing Phytates

While soaking is the most accessible method, other techniques can also reduce the phytic acid content in oats:

Fermentation: The lactic acid bacteria used in sourdough starters can help break down phytic acid. Fermenting grains, such as using a sourdough starter with your oats, is another effective approach.
Sprouting: Germinating grains naturally initiates the breakdown of phytic acid as the plant's enzymes activate. While more involved, sprouting is a powerful method for reducing phytates in various grains.
Cooking: Cooking, especially pressure cooking, can also significantly reduce phytic acid content. A long cooking time, particularly after soaking, provides a synergistic effect.
Pairing with Vitamin C: Consuming oats alongside a source of Vitamin C, such as berries or citrus, can help improve the absorption of iron.

Conclusion

Deciding how long to soak your oats to remove phytic acid depends on your dietary goals and cooking methods. An overnight soak in plain water is a good starting point, but adding an acidic medium or a high-phytase grain provides more effective results, especially for those seeking to maximize mineral absorption. Ultimately, soaking oats is a simple, traditional food preparation technique that can help you unlock more of the nutritional goodness this superfood has to offer. For most people with a balanced diet, the presence of phytic acid is not a major concern, but for those with particular sensitivities or high-grain diets, this simple step can make a big difference in digestion and nutrient uptake.

For more in-depth information on the benefits and potential downsides of phytic acid, the National Institutes of Health provides excellent resources based on studies of phytic acid supplementation in controlled models.

Frequently Asked Questions

Phytic acid is a natural compound found in the bran of seeds, nuts, and whole grains, including oats. It binds to minerals like iron, zinc, calcium, and magnesium, and can reduce their absorption by the body.

Yes, for most people on a varied diet, eating unsoaked oats is perfectly safe and healthy. The body can compensate, and the total amount of phytic acid consumed is generally not enough to cause serious issues, especially if you get minerals from other food sources.

Adding an acidic medium, like lemon juice or apple cider vinegar, helps activate the limited phytase enzymes present in the oats and creates a favorable environment for the breakdown of phytic acid. This process is more effective than soaking in water alone.

While all oats benefit from soaking, steel-cut oats, being less processed, generally benefit from a longer soak. Rolled or quick oats are already partially processed, but an overnight soak (8+ hours) with an acidic medium is still recommended for maximum phytic acid reduction.

If you forget, even a shorter soak of a few hours is better than none. You can also cook the oats after a short soak to further help with breaking down phytic acid.

It depends on the recipe and your preference. For overnight oats, you typically don't drain. If cooking, draining and rinsing can wash away some of the released starches, which may improve the texture and remove any lingering sour taste.

Phytic acid also possesses beneficial antioxidant properties, so removing it completely isn't necessarily ideal. The goal is not to eliminate it entirely, but to reduce its binding effect on minerals to a manageable level, particularly for those with certain dietary needs.