Weekend Musings: Soaking Oats

Remember, I am not a nutritionist. Everything I’m about to write came from my own experiences and from independent researching. If you haven’t yet read my musing about being a nutrition skeptic, I highly recommend it!

For a long time, I’ve noticed that my stomach is happier after eating overnight oats compared to stovetop oats. I had no idea why. Even when I made a larger portion of overnight oats (they are typically smaller in volume than the same measurement of dry oats on the stove), it would still leave me with a happier gut.

Matcha Yogurt Overnight Zoats! ??

A photo posted by Lauren Smith (@oatmealartist) on

When Giselle submitted her guest post for the Spiced Plantain Brownie Baked Oatmeal, she included an instruction to soak the oats in an acidic liquid overnight. Curious, I emailed back to ask why. She responded, “Soaking the oatmeal (or any other whole grain) in acidic liquid is supposed to break down the phytic acid to make them more nutritious and digestible. Rinsing them removes most of the lemon flavor.”

Normally, hearing something like “break down the phytic acid” would set off my BS radar. ? I take being a nutrition skeptic very seriously, and I think there is a lot of nonsense being thrown around. But considering the very real, noticeable difference in my digestion after eating overnight oats vs. stovetop oats, I was intrigued.

Googling “soaking oats” brings up pages of results. Here’s what people are saying:

  • “Seeds are meant to pass through the system relatively undigested so they can be planted elsewhere (think in nature). ‘Soaking’ whole grains can make them more digestible and help your system obtain all the nutrients in the food.” – Kitchen Stewardship
  • “Nuts have phytic acid.  Phytic acid is also found in grains and legumes.  Just as with nuts, soaking grains and legumes is essential for proper digestions. When eating grains and legumes that haven’t been soaked, the phytic acid binds to minerals in the gastrointestinal tract and can not be absorbed in the intestine and to many bound minerals can lead to mineral deficiencies.” – Whole Lifestyle Nutrition
  • “Soaking oats used to be par for the course in oatmeal instructions, but in the 1920s, convenience began to trump tradition (and flavor). As the demand for quick-cooking oats grew, the soaking step was eventually removed.” – Tasting Table
  • “Their starches break down which improves digestibility and their natural phytic acid (which all plants contain) is greatly reduced that makes them more easily absorbed by your body.” – One Green Planet

Mango-Coconut Overnight Oatmeal with Puffed Wild Rice

A photo posted by Lauren Smith (@oatmealartist) on

So was I–a devout nutrition skeptic–going to put my faith in this theory? I decided to seek more scholarly sources. As an NYU student with access to online journal databases, this was an easy task for me.

According to Raj Kishor Gupta, “Monogastric animals” (i.e. creatures with a single stomach) “including poultry and humans are unable to metabolize phytic acid due to the lack of sufficient level of phytate degrading enzymes activity in their digestive tract and it is largely excreted in their manure” (2015, p. 677). In other words, our bodies don’t have enough enzymes to break down the nutrients in this food, so all that good stuff just ends up in the toilet. Oops!

And what nutrients are we “passing” on (haha)? According to Gupta, phytic acid “inhibits absorption of iron, zinc, calcium, magnesium and manganese. Removal of phytic acid increases bioavailability of many cations and thus nutritional value of meal” (2015, p. 678).

Indeed, Gupta reports that “complete submergence of grains in water” did reduce the phytic acid in sorghum flour by as much as 21%. When soaking pearl millet, it increased the “vitro solubility of iron and zinc” by as much as 23 % (2015, p. 678).

Okay, so this appears to be a real thing. I’m pretty convinced. Having only soaked my oats in water or nut milk (not an acid), I decided to try the acidic approach.

Shirley Temple Overnight Oats

A photo posted by Lauren Smith (@oatmealartist) on

Every blog post I cited above gave me different instructions for how to do this (one even instructed me to soak it for a full 24 hours! Not happening…), so I kind of just winged it. I covered 1/4 cup quick cook steel cut oats with lukewarm water with an unmeasured splash of lemon juice. I left it on the counter at room temperature overnight.

In the morning, I ran it through my nut milk bag and rinsed it. Then, I cooked it on the stove with cashew milk and turned it into Cardamom Fudge Oatmeal. Nummmmmy.

At first, it seemed the same: both texture and flavor-wise (no, I couldn’t taste lemon). The process of soaking and then cooking resulted in a volume equal to what you would get with stovetop oats (as opposed to the smaller volume of overnight, refrigerator oats). Upon finishing, I had the same feeling of fullness that I usually get at the end of a bowl. For a few minutes, I decided this was the quackery I had expected it to be.

That changed about 30 minutes later. Typically, that is when an uncomfortable cramping starts to set in, like the oatmeal is stuck in my intestines or something. With these soaked oats, that feeling was significantly lighter than usual, and–to my surprise–I actually got my appetite back within a couple hours. This might sound obvious to the average person, but as someone with GI issues, proper digestion has not always come easy for me. This was a particularly impressive feat considering I had been experiencing tummy troubles all week.

The next day, I tried it with apple cider vinegar. I hate the flavor of this stuff (yes, even the good brands), but considering I couldn’t taste any lemon in the previous day’s breakfast, I felt confident. Sure enough, I could not detect any apple cider vinegar flavor. Yay!

Sadly, my digestion on this second day was more typical for me (i.e. not good). After an hour, I still felt quite a bit of cramping. ? Perhaps I am still getting more of these elusive micronutrients, but in terms of how I am physically experiencing the digestion, it was just as unpleasant as usual. I seem to have trouble dealing with all this fiber or something. Hooray, IBS!

Granted, this was only a two-part trial, and the effects on either day could have stemmed from a number of factors beyond soaking. (For one, I did this experiment while PMSing, so . . .?) I look forward to continuing this experiment, and if you try it yourself, let me know how it worked for you!

Gupta, R. K., Gangoliya, S. S., & Singh, N. K. (2015). Reduction of phytic acid and enhancement of bioavailable micronutrients in food grains. Journal of Food Science and Technology, 52(2), 676–684. http://doi.org/10.1007/s13197-013-0978-y

About Lauren Smith

Lauren is a herbivore, Slytherin, and connoisseur of oats. She is a former teacher who is currently studying to earn a master's degree in curriculum development. You can follow her on Instagram, Twitter, Pinterest, and Facebook.

9 Responses to Weekend Musings: Soaking Oats

  1. Kelsey says:

    I was soaking steel cut oats for a while and I did notice I was digesting them slightly better (i.e. less like seeds..). That also made them quicker to cook and gave them a softer texture, which is what kept me doing it until I ran out of oats. I’ve also heard a similar thing about peanut butter, how its supposed to be harder to digest than other nut butters because peanuts are technically legumes. And I think that might be true for me, unfortunately 🙁

    • Lauren Smith says:

      Bummer. I’ve heard that, too, but I’ve yet to notice a difference between when I eat peanut butter vs. almond butter. I do notice that when I eat steel cut oats, I experience far more digestion problems, so I should try this soaking method with that cut. (And anything that makes them faster to cook is a WIN in my book.)

  2. Jas says:

    I soak oats because I find them creamier and quicker to cook if turning into oatmeal or for overnight oats because to be honest I think I prefer them uncooked to cooked. I too suffer with Gastro issues and cant tolerate too much fibre. I will give it a go soaking in something acidic but I will definitely rinse it off like you did because acid also sets my stomach off!

    • Lauren Smith says:

      Yes. I need fiber and yet too much sends me into misery. Gastro issues seem to dominate my life some days! I agree that I like how creamy and quick they are (but I do like mine cooked).

  3. Cathy says:

    Hmm… Interesting. I sometimes use CCK’s “Voluminous Oatmeal” trick- I add more liquid to my oats than usually, I cook them and stop before the liquid is completely absorbed and then leave it overnight, the next day the liquid is absorbed and the amount of oatmeal has doubled!
    I’ve also heard about soaking oats before baking them. I tried this method but haven’t noticed any difference in my baked oatmeal so I stopped 😀 but I don’t have any gastric problems.
    I do soak beans and chickpeas. Should I also start soaking rice?

    • Lauren Smith says:

      The soaking part of beans is much more necessary (but I think it emphasizes the point of soaking things). Hmm I don’t know anyone who soaks rice and I feel like that would ruin the texture, no? But it’s worth looking into.

      • Cathy says:

        I conducted my own experiments (but only with lemon juice), did taste-testing (several times).
        Making stove top oatmeal with soaked oats is easier: it requires less liquid, is quicker and makes oatmeal creamier.
        But! I also tried making baked oatmeal with soaked oats… And it was a failure. First I added some milk… oatmeal turned too runny. Then I stopped adding any liquid, it was too runny for my liking too. I like my baked oatmeal to be dense. I made baked oatmeal with non-soaked oats… and it was much more delicious!
        My results: I’ll keep making stove-top oatmeal with soaked oats (if I remember to soak them ;)) but I’ll stick to non-soaked oats with baked oatmeal.

  4. Cassie says:

    Oh I wish you the best of luck with repairing your digestion, Lauren! I’ve been thinking about investing in sprouted or soaked beans for my digestion as well. I really want to see if there is a true difference in how I feel with them as well as soaked oats!

  5. Nandarani says:

    I have read and digested numerous articles and blogposts and came to this site during a search for, trying to get an answer in specific temperature if I could…. how high does the heat in cooking oats actually need to be – to preserve/release minerals – especially magnesium and zinc? Do soak, and do use apple cider vinegar, and do add ground rye groats, which contain large amounts of phytase, rye has the most – and its evidently been proven that adding them, to the acid medium, when soaking high phytic acid grains like oats… helps. The temperature of around 175 degrees disables phytase. Using the ‘warm’ function on my GoWise pressure cooker, which never rises above around 156 degrees, is the way I’ve been ‘cooking’ my oats, lately. After soaking for 12+ hours without consistent heat, just warming occasionally, before going out I just put the pressure cooker on ‘warm’ and return hours later…. as in…. 5 hours later or more…. and consider them ready. The taste is great, and I also feel very good after eating the oats – a better ‘post digestive effect’ than I ever imagined could be true with already good feelings producing oats! Yay Lauren. Best wishes to you in your work – education at NYU. Was born in Manhattan and lived there for quite some time. Maybe you are studying something that is as intrinsically interesting to you as the subject of this blog is – and that you can use once you graduate or maybe even combine with writing and this blog.

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