Nuts and seeds can be a terrific nutrient-dense snack or addition to a meal, but like grains and legumes, they can also contain substances that interfere with the body’s ability to absorb nutrients.
Just as the process of soaking, sprouting or fermenting grains reduces the anti-nutrient content and makes them more beneficial to the body, the simple process of soaking nuts improves their nutrition.
Enzyme Inhibitors in Nuts and Seeds
Like grains, raw nuts (and especially raw seeds), contain moderate levels of phytic acid and enzyme inhibitors. Phytic acid is biologically necessary for the plant, as it helps safeguard the nut or seed until proper growing conditions are present and germination can occur.
These enzyme inhibitors prevent the seed from sprouting prematurely, but can cause potential problems in humans by binding to nutrients in the body and contributing to nutrient deficiencies and digestive system irritation.
Seeds and nuts store phosphorus as phytic acid and it becomes a phytate when it binds to a mineral. In the body, this process can stop nutrients from being absorbed in the digestive system and reduce the digestibility of these foods.
In other words, just because nuts and seeds are considered good sources of protein and nutrients, doesn’t mean your body can absorb these nutrients. All plants contain phytic acid in some levels, but grains, legumes, nuts and seeds typically contain the highest levels.
It is also important to note that phytic acid may not be entirely bad, but the dose makes the poison. Modern diets high in processed grains and low in nutrient dense fats and minerals may increase the likelihood of nutrient absorption problems and make it even more important to reduce phytic acid levels in food.
Research is finding that phyic acid in certain levels may have a protective effect in the body and a secondary messenger role in cells. It seems that in order to provide this beneficial effect, it must be balanced by certain fat soluble vitamins and other nutrients and the person must be able to absorb these.
This is why it can be helpful to reduce the phytic acid content of seeds and nuts and make the nutrients more available and this step is especially important for young children who are still developing the enzymes to break down these plant foods (ever seen undigested nuts, grains or seeds in a toddler’s stool? This is partially due to their inability to digest certain proteins and nutrients in these foods).
The Importance of Soaking Nuts and Seeds
Some phytic acid is naturally neutralized during the digestive process, but foods that are especially high in phytic acid benefit from the process of soaking (and sometimes sprouting) and dehydrating to further reduce the anti-nutrient content.
Soaking in a simple mineral solution (like salt) and low-temperature dehydrating helps to break down much of the phytic acid and make the nutrients in nuts more available to the body.
While many traditional cultures naturally soaked or sprouted seeds, this step is hardly ever taken with large scale production since it is time consuming. It is, however, simple and inexpensive to do at home and can greatly increase the nutrient content of the seeds and nuts you consume.
How to Soak Seeds and Nuts
There are two parts to soaking nuts and seeds: warm water and salt.
The warm water will neutralize many of the enzyme inhibitors and increase the bioavailability of many nutrients, especially b-vitamins. The salt helps activate enzymes that deactivate the enzyme inhibitors present in nuts.
When soaking grains or beans, a more acidic substance is often used, but since nuts and seeds contain less phytic acid than grains/legumes but more enzyme inhibitors, the salt is more beneficial.
Within 7-24 hours (depending on the seed or nut), many of the enzyme inhibitors are broken down. At this point, a dehydrating process beings to return the nuts to a crisp texture. I’ve found that nuts that have been pre-soaked taste much better and don’t end up undigested in little ones diapers.
What You Need:
- 2 cups of raw, organic nuts or seeds (it is better to soak one kind at a time)
- 3-4 cups of warm filtered water (to cover nuts)
- 1 tablespoon of salt
What to Do:
- Place the warm water in a medium bowl or jar (half gallon or larger). Add the salt and let dissolve.
- Add the nuts or seeds, making sure they are completely submerged in the water.
- Leave uncovered on the counter or other warm place (not the refrigerator) for at least 7 hours, preferably overnight.
- Rinse in a colander and spread on a baking sheet or dehydrator sheet. Bake in the oven at the lowest temperature (150 F is optimal) or dehydrate until completely dry. This step is important, as any remaining moisture in the nuts or seeds can cause them to mold. Dehydrating time can often be up to 24 hours, so a dehydrator simplifies the process but isn’t necessary.
- NOTE: If you plan to use nuts or seeds to make homemade almond milk or any other variety, this is the optimal time, as they are already softened. This is an important step in the homemade nut milk process as the enzyme inhibitors are mostly removed and the nuts are already softened to make a more creamy milk.
A Step Further: Sprouting
Sprouting goes a step further from soaking and reduces the levels of enzyme inhibitors even more. Often, products sold as sprouted nuts and seeds are merely “activated” by the process of soaking, but certain seeds can sprout after several cycles of soaking, rinsing, and giving exposure to air to allow germination.
Raw pumpkin and sunflower seeds are the best candidates for sprouting, and some nuts like pecans and walnuts will not sprout. If you want to add this additional step, soak the seeds with the process above. Then rinse and follow the normal sprouting process until sprouts occur. This will only work with non-irradiated seeds and only certain varieties. This step does further reduce enzyme inhibitors, but except for those with digestive problems or severe nutrient deficiencies, this step is not often necessary and soaking alone is sufficient.
To Soak or Not to Soak?
Not all nuts and seeds can be easily soaked. Flax and chia seeds gel when soaked and are very difficult to work with. For any nuts or seeds that can be soaked, you’ll have to weigh the benefits and see if the process is worth the time investment for you.
Personally, I like this step simply because the seeds and nuts taste so much better once they are soaked and it makes the nutrients more available. If you consume a lot of nuts or seeds, this process may be especially helpful to you, as the higher levels of enzyme inhibitors may be more problematic. Soaking and dehydrating organic raw nuts and seeds also creates an end result similar to roasted nuts, but without the added vegetable oils or high temperature roasting that can damage the nutrients and enzymes in these foods.
High quality pre-soaked and sprouted nuts and seeds are now available (I personally like this brand), but you can accomplish the same end result by soaking your own at home. It takes a little time investment, but is well worth the taste and nutrient benefits in my opinion.
Do you have any experience with soaking nuts and seeds? What method do you use?
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Hi. I bought a bag of cashews at the Whole Foods Market for the first time while driving through the US. they weren’t cheap. When I opened them up to eat, they were terrible. Not dry and crunchy like I thought they’d be, but soft and chewy. Obviously were soaked, I guess, as I’ve never had them before. But after reading this, I guess they were not properly dehydrated. Reminded me of nuts that had got wet and soggy like if they were put in the fridge.
nooooo you bought raw cashews, which are chewy and not cruncy (since they are not roasted). Raw cashews are good for soaking, cashew milk, gravies, etc. Roasted cashews are good for snacking
I have a question: I get most of my nuts and seeds from a homemade granola I always have around. Would I be able to dry the nuts and seeds during the 25 minutes at 350 degrees that I cook the granola at?
Or would I have to soak, dry, and then roast for 25 minutes? Or would that 25 minutes be harmful to the nutrients I just freed up?
Roasting can harm some of the nutrients. Have you ever tried a soaked and dehydrated granola? If you did want to just roast, it should be fine, but I’d keep the granola in the freezer until ready to use, just in case there was any moisture left.
This is really helpful! If we plan to use the nuts for nut milk, is dehydration necessary? Or can the nuts be used directly after soaking and rinsing?
They can be used right after soaking and rinsing and are even better for nut milk at this stage.
To make nut milk what is the ratio of nuts to water?
A typical ratio is 1:3, with coconut flakes it’s 1:2
Will soaking also help bind oxalates ?
Hi Katie! Thanks for this. If you were going to make a cashew butter, do you think you’d soak, dehydrate, and the grind, or would you skip the dehydration step?
I would definitely dehydrate still. If not, there would be moisture in the nut butter, which would cause it to spoil quickly.
How long do you bake them in the oven at 150 degrees?
I use my nuts in smoothies. I soak them and then freeze them rather than drying them. Do I still need to dry the nuts in order to completely remove the physic acid?
I’d love to share this with my mom, who has acute kidney disease. However, because of this she has to have next to no salt in her diet. What do you recommend for people in the same or similar situation?
There is a possibility that the salt is used as a dessicator, rather than because it is involved in any chemical processes. If that is the case, you could try using the same amount of sugar instead, as it will also act as a dessicator. Alternatively, throw in some cider vinegar or lemon juice (apparently this is supposed to help); or just soak them in normal water (but you won’t get the full nutritional benefits this way).
What if you want to make almond butter? Should the almonds be completely dehydrated?
Yes. If not, any remaining moisture may cause the almond butter to spoil quickly.
I have been soaking almonds for years and now soak pecans. I can’t believe how good they taste! I have made almond butter with them and it’s so much better than store bought. 🙂 my system is to soak them during the day, then put them in the oven all night.
For health reasons, we do not use sodium chloride in our kitchen; we prefer to use potassium chloride instead. Does the salt need to be sodium based or will non sodium salts work as well?
Well it is quite unlikely that your potassium chloride salt is 100% potassium chloride; potassium chloride has a slightly different (less pleasant) taste to sodium chloride so the two are usually mixed together to create a low-sodium salt, rather than non-sodium salt.
However even if your salt is 100% potassium chloride, theoretically it shouldn’t matter too much as sodium and potassium salts have almost identical chemical properties; but it will depend on the exact mechanism the enzyme inhibitors are denatured by. I’ll spare you all the technical details but in a nutshell (pun completely intended) there are certain chemical reactions that go one way if you use a lithium salt, and a different way if you use a potassium salt due to the size of the metal ion; sodium is in the middle so it is likely the reactions (to deactivate the enzyme inhibitors) will still work if you use potassium, but perhaps not quite as well as if you were to use sodium. For example, the “yield” of deactivated enzyme inhibitors may be 75% for sodium and 45% for potassium. Soaking the nuts for longer will help – so try for the full 24 hours rather than 7!
Hope this helps 🙂
Great post as usual:)
How do you soak the more difficult seeds that gel, like chia seeds?
Soaked walnuts have a much richer almost buttery flavor and definitely none of the bitterness that plain raw walnuts have! Also, I have found almonds much easier to digest, but cashews were not our favorite after soaking. I may not have dehydrated them long enough, or the soaking process just left them a little more chewy. I love my soaked nuts though!
Thanks for that comment about soaking walnuts. I must try it as I find walnuts often bitter.
I baked walnuts in the oven at 250F ( lowest temperature available) for an hour in order to get them to become crisp again, after soaking them in lightly salted filtered water for 6 hours. But they turned black where the skin had been exposed, looking very disgusting. Could someone tell me what caused the walnuts to turn black? Are these nuts still safe to consume? I have no plan to own a dehydrator for the moment as I have yet to find one that’s compact enough, and using the oven is the only option I have now. Please help. Thank you.