Do Boiling Potatoes Remove Oxalates? A Deep Dive into Leaching

December 27, 2025 •

4 min read

Scientific research confirms that cooking methods can alter the nutrient and antinutrient content of foods like potatoes. A common question for those monitoring their diet is, do boiling potatoes remove oxalates, and how much can actually be eliminated through this simple process?

Quick Summary

Boiling potatoes effectively leaches soluble oxalates into the cooking water, significantly reducing their content when the water is discarded. Peeling and cutting the potatoes increase the surface area, enhancing the removal process. Other methods like steaming or baking are less efficient for this purpose.

Key Points

Boiling is Effective: Boiling can remove a significant portion of soluble oxalates from potatoes by leaching them into the cooking water.
Discard the Water: To successfully reduce oxalates, you must discard the water used for boiling, as it contains the leached compounds.
Preparation Enhances Removal: Peeling and cutting potatoes into smaller pieces increases the surface area, making the leaching process more efficient.
Boiling Outperforms Other Methods: Research shows that boiling is more effective for oxalate reduction than steaming or baking.
Baking Can Concentrate Oxalates: The dehydration that occurs during baking can concentrate the oxalates rather than removing them.
Consider Your Diet: The need to reduce oxalates varies by individual, especially for those with kidney stone concerns or on a specialized diet.

The Science Behind Oxalate Reduction in Potatoes

Oxalates are natural compounds found in many plants, including potatoes, that can bind with minerals like calcium, potentially leading to issues such as kidney stones in susceptible individuals. The good news is that oxalates are soluble in water, a property that forms the basis for their removal through proper cooking.

How Boiling Works to Leach Out Oxalates

The most effective way to reduce the oxalate content in potatoes is by boiling. The process, known as leaching, involves the movement of soluble compounds from the solid food into the surrounding liquid. When you boil potatoes, the hot water draws the soluble oxalates out of the potato cells. For this method to be successful, it is crucial to drain and discard the cooking water completely. If the water is used for gravy or soup, the leached oxalates are simply reintroduced into the meal.

The Impact of Preparation on Oxalate Levels

To maximize the leaching effect, peeling and cutting the potatoes before boiling is highly recommended. Peeling removes the skin, which can contain a higher concentration of oxalates. Cutting the potato into smaller, uniform pieces increases the total surface area exposed to the boiling water, allowing more oxalates to leach out efficiently. A study on vegetables, including potatoes, found that boiling could reduce soluble oxalate content by as much as 30-87% depending on the vegetable, far exceeding the reduction from steaming.

The Double-Boiling Method

For those on a very strict low-oxalate diet, a "double-boiling" method is sometimes used. This technique involves boiling the potatoes once, discarding the water, and then boiling them a second time in fresh water. This two-stage process can further minimize the remaining oxalate content, though it is more intensive and results in more nutrient loss.

Comparison of Cooking Methods for Oxalate Reduction

Different cooking methods have varying impacts on oxalate levels. Understanding these differences can help you make informed choices based on your dietary needs.


Cooking Method	Effectiveness for Oxalate Removal	Mechanism	Potential Downsides
Boiling	Highly effective (30-87% reduction of soluble oxalates)	Leaching soluble oxalates into water; discarding the water is essential.	Can cause the loss of other water-soluble nutrients, such as Vitamin C.
Steaming	Moderately effective (5-53% reduction)	Leaching and some thermal breakdown via condensation.	Less contact with liquid means less leaching compared to boiling.
Baking	Not effective; may increase concentration	No leaching occurs; moisture loss concentrates oxalates.	Significantly increases the relative oxalate concentration due to water evaporation.
Microwaving	Ineffective	Lack of a leaching mechanism.	Oxalates are retained within the food.
Frying	Ineffective	No leaching occurs; high heat does not degrade oxalates sufficiently.	Similar to baking, the concentration may increase due to moisture loss.

Step-by-Step Guide to Boiling Potatoes for Lower Oxalate Content

Select and Wash: Choose your potatoes. Russet potatoes tend to be higher in oxalates, while new potatoes or red-skinned varieties may be lower. Wash the potatoes thoroughly to remove any surface dirt.
Peel the Skin: Using a vegetable peeler, remove the entire skin of the potato. Since oxalates can be more concentrated in the skin, this is a vital step.
Cut into Smaller Pieces: Dice the peeled potatoes into smaller, uniform-sized cubes (e.g., 1-inch). This significantly increases the surface area, promoting more efficient leaching.
Boil in Abundant Water: Place the potato cubes in a pot and cover them with a generous amount of fresh, unsalted water. Bring the water to a rolling boil.
Cook Until Tender: Allow the potatoes to boil until they are tender when pierced with a fork. Cooking time will vary based on the size of the pieces.
Drain and Discard Water: This is the most crucial step. Drain the cooked potatoes completely in a colander and discard the oxalate-rich water. Do not reuse this water.
Rinse (Optional): For an even further reduction, you can rinse the hot, drained potatoes with fresh, hot water.
Use as Desired: Proceed with your recipe. The potatoes are now ready for mashing, frying, or using in a salad, with a significantly lower oxalate count.

Conclusion

For those seeking to reduce their dietary oxalate intake, boiling potatoes is a scientifically supported and effective strategy. The process relies on the solubility of oxalates, which allows them to be leached into the cooking water. By peeling, cutting into small pieces, and, most importantly, discarding the cooking water, you can achieve a significant reduction in the oxalate content of your potatoes. While this method also removes some water-soluble vitamins, it is a key preparation technique for those on a low-oxalate diet. Always consult a healthcare professional for personalized dietary advice, especially if you have a history of kidney stones or other oxalate-related health concerns. For further reading, an academic review on oxalate levels in foods can be found here: Oxalate in Foods: Extraction Conditions, Analytical Methods, and Food Content Tables.

Frequently Asked Questions

No, you should not drink the water used to boil potatoes. It contains the oxalates that have leached out of the potatoes during cooking and is specifically discarded to avoid consuming them.

Yes, peeling potatoes is an important step in reducing their oxalate content, as the skin can contain a higher concentration of the compound.

No, baking is generally not recommended for reducing oxalates. The process removes moisture and can actually concentrate the oxalate content rather than reducing it.

Boiling can significantly reduce the soluble oxalate content, with some studies showing a reduction of 30-87% in different vegetables.

The most effective method is to peel the potatoes, cut them into small pieces, boil them in a large amount of water, and then discard the water completely.

Different varieties of potatoes have different oxalate levels. Some studies suggest that russet potatoes might have higher levels than new potatoes or red-skinned varieties, and oxalate concentration can vary depending on growing conditions.

Many other high-oxalate vegetables can benefit from boiling and draining, including spinach, kale, beetroots, and rhubarb.