In our kitchen we soak walnuts and almonds overnight before eating them. In Iranian family tradition, walnuts have always been part of the breakfast table alongside feta or cream cheese, butter, bread, and tea. Some families soaked them, others did not. We started soaking ours because the difference in flavor is immediately noticeable.

But because this is a site that tries to separate what is well-supported from what is marketing, it is worth being honest about what the research actually shows, including where the benefits are clear and where they are less certain than some wellness sources suggest.

What nuts contain that soaking addresses

Walnuts and almonds, like all nuts and seeds, contain compounds the plant produces to protect itself. These compounds are not harmful in typical dietary amounts, but they can reduce how much nutrition you extract from the nut and affect how easy they are to digest.

Phytic acid

Phytic acid is a compound found in most plant foods including nuts, grains, and legumes. It can bind to minerals like iron, zinc, calcium, and magnesium, forming complexes that the body cannot easily absorb. This is sometimes described as making the minerals unavailable. The effect is real but should be kept in proportion. Phytic acid is one factor among many that affect mineral absorption, and most people eating a varied diet are not significantly affected by the phytic acid in a handful of nuts.

It is also worth noting that phytic acid is not purely a negative. It has antioxidant properties and has been studied for potential protective effects against kidney stones and certain cancers. The anti-nutrient framing captures only part of the picture.

Enzyme inhibitors

Raw nuts contain enzyme inhibitors that can interfere with the digestive enzymes that break down food. Some people who eat raw nuts report bloating, heaviness, or difficulty digesting them, though there isn't strong human evidence establishing enzyme inhibitors as the specific cause. Many people simply find soaked nuts easier and more pleasant to eat, whatever the underlying reason.

Tannins

Tannins are the compounds responsible for the bitter, slightly astringent taste of raw walnuts in particular. They are concentrated in the papery brown skin. When you soak walnuts overnight the water turns brown. That is the tannins leaching out. The result is a noticeably milder, slightly sweeter walnut that is much more palatable, especially for children. This is arguably the most immediately noticeable benefit of soaking and the one that requires no scientific qualification. You can taste the difference.

What soaking actually does

Soaking does a few things that are well-supported by both research and practical experience:

Where the evidence is more nuanced

Here is where we want to be especially careful, because this is the claim most often overstated online. A 2020 study in Food Chemistry directly tested soaking on almonds, hazelnuts, peanuts, and walnuts, comparing raw nuts to nuts soaked in salt water and in plain water for varying lengths of time. The differences in phytate levels between soaked and unsoaked nuts were small and inconsistent, ranging from about 12% lower to 10% higher depending on the nut and soaking method. Soaking did not improve the phytate-to-mineral ratio, and in some cases, particularly for chopped nuts, mineral concentrations were actually lower after soaking. The researchers concluded there is no good evidence that soaking improves mineral bioavailability in nuts, unlike in legumes and grains, where soaking does make a meaningful difference. If you soak nuts hoping for a meaningful boost in mineral absorption, the current research does not support that expectation. If you soak them because you prefer the softer texture and milder flavor, that reason stands on its own.

Walnuts and almonds specifically

Walnuts

Soak overnight in filtered water: 6 to 12 hours

Walnuts benefit most visibly from soaking because of their high tannin content. The bitterness reduction is significant and immediately noticeable. After soaking overnight in filtered water, drain and rinse thoroughly. The soaked walnut has a softer, milder flavor that children and adults who find raw walnuts too bitter tend to enjoy much more.

Keep the papery brown skin on. It contains ellagic acid, a polyphenol with anti-inflammatory research behind it, and removing it reduces the nutritional value of the walnut.

Store soaked walnuts in the fridge and use within 2 to 3 days. They do not keep as long as raw walnuts once soaked.

Almonds

Soak overnight in filtered water: 8 to 12 hours

Almonds benefit from soaking mainly for texture. The almond skin contains tannins that contribute to a slightly bitter, astringent taste, and soaking softens the skin significantly. After soaking, the skin slips off easily if you choose to remove it, giving you a softer, creamier almond. Current research does not support the idea that removing the skin meaningfully improves mineral absorption.

One trade-off worth knowing: the almond skin also contains flavonoids with antioxidant value, so removing it means losing some of that. Whether you peel soaked almonds or not comes down to texture preference rather than a clear nutritional advantage either way.

Store soaked almonds in the fridge and use within 2 days.

An important note: roasted nuts cannot be activated

Soaking only works on raw, unroasted nuts. Heat destroys the enzymatic activity that makes soaking effective. A roasted almond or walnut has already had its biological potential deactivated by heat. You can soak a roasted nut for 24 hours and nothing meaningful will happen because the enzymes are gone. For soaking to work, use raw, unsalted, unroasted nuts.

How we do it

Our method

  • Place raw walnuts or almonds in a glass bowl
  • Cover completely with filtered water. Use about twice the volume of water to nuts
  • Leave on the counter overnight: 6 to 12 hours for walnuts, 8 to 12 hours for almonds
  • In the morning, drain and rinse thoroughly under cold filtered water
  • Eat immediately or store in the fridge in a covered glass container for up to 2 to 3 days
  • We use plain filtered water with no salt, mainly out of habit and simplicity, not because research shows plain water works better. A 2020 study that tested both salted and unsalted soaking did not find plain water to be nutritionally superior.

Should you soak walnuts before eating?

You do not need to soak walnuts before eating them

Raw walnuts are perfectly fine for most people. We soak ours because soaking softens the texture and noticeably reduces the bitter, astringent flavor of the walnut skin. Current research does not show that soaking walnuts dramatically improves mineral absorption or removes large amounts of phytic acid, so we think of soaking as a traditional preparation method and a matter of taste rather than a nutritional requirement.

The honest bottom line

Soaking walnuts and almonds overnight is a simple, low-effort practice, and the honest, evidence-based summary is simpler than a lot of wellness content suggests. We soak walnuts mainly because we prefer their softer texture and milder flavor. Soaking does reduce tannins in a way you can taste and see. Current research does not show a meaningful improvement in phytate reduction or mineral bioavailability in nuts, unlike the clearer benefits soaking provides for legumes and grains.

We soak our walnuts and almonds because they taste noticeably better, our children eat them more willingly, and they feel easier to eat. Those are sufficient reasons on their own, and the traditional food cultures that developed this practice did not need clinical trials to confirm what they could observe in practice.

If you are not currently soaking your nuts, try it for a week and notice whether you can tell the difference. With walnuts in particular, the flavor improvement alone is worth the minimal effort of leaving a bowl of water on the counter overnight.