What’s the difference between corn meal and corn masa?

It’s a good question, because on an intuitive level one would think that if a corn tortilla is a simple pancake made of ground corn, there really shouldn’t be that much difference between finely ground corn meal and masa harina (literally “dough flour”). In reality there’s a huge difference, which can be summed up in a single word: nixtamalization. Yeah, that’s a mouthful. It comes from the Aztec word “nixtamal” which, loosely translated, means “ash dough.”

Not very appetizing by the sound of it. However what ancient Mesoamericans discovered 3,500 years ago is that when you boil and then soak raw corn kernels together with ashes, some very interesting things happen. Notably, the outer hulls (pericarps) of the kernels loosen to the point that they can be slipped off. Further, what’s left — the endosperm and germ of the kernels — becomes quite soft and pliable, easily ground into a dough that’s perfect for making tortillas.

So nixtamalization is all about heat and water then? Er, not quite. The key component is really the ash, which, long-time readers of joepastry.com may remember, has a high pH. Add a handful to a pot of water and you get an alkaline solution that goes to work dissolving the glues that hold the walls of the pericarp cells together (the hemicellulose and pectins). The pericarp loosens and falls off, and the endosperm swells as it takes in more and more of the chemical-laden water. As it does, the tight bundles of starch molecules in the endosperm start to come apart. What you get, once the corn is finally drained and washed, is a processed corn product that’s easily ground into a dough that’s just smooth enough and just elastic enough to be formed into a thin cake like a tortilla.

Neat. But it raises the question: how did the ancient Mesoamericans hit on this process? Unknown. It may have started when someone mixed a few wood ashes in with some corn gruel (a common technique that indigenous American peoples used to lighten — really leaven — cakes made from grains). But who knows? Wood ashes (which contain potassium carbonate) weren’t the only alkaline compounds available to the peoples of that time. Naturally occurring lime (calcium carbonate-rich limestone and/or chalk deposits) were also used, as were the ashes of burned mussel shells.

These days, most people who want to make their own corn masa use a commercially-made product that simply goes by the name of “cal” in Mexico. Calcium hydroxide is what it is, commonly known as “slaked” (dissolvable) lime in America. It can be found in most Mexican markets in the spice section.

Buying the cal and boiling and steeping the corn is the easy part, however. The real challenge when it comes to making one’s own corn masa is the grinding. Getting it fine enough to make tortillas is no easy task. Food processors aren’t good enough. What’s needed is either a plate grinder or a good, old-fashioned metate. I’ve never used one, but I can imagine they call for more elbow grease than I’d be willing to put in for home-made tortillas. But those of you who might be interested, knock yourselves out! You can get them in Mexican markets as well. They cost less than you’d think.

15 thoughts on “What’s the difference between corn meal and corn masa?”

  1. Thank you for taking the time to publish this information.
    However, I have three remaining questions.

    1. when it says soak corn meal. is this fresh corn that has been milled? or from a bag i bought?
    2. after I soak the corn and rinse, don’t I have to dry it
    before grinding it? no article talks about after the soaking.
    Now I have cooked soaked corn and if you could elaberate on what is next that would be awsome.
    3.If I use wood ash I don’t need to use the lime water?
    also what makes blue corn? (blue tortillia)
    Thanks again you have been a big help.
    Learning to do more from my kitchen and less from store products.

    1. Hey Jacqueline!

      If you’re making your own masa you’ll want to soak whole dried corn kernels. They can be a little tough to find, but it is possible. I’d also use cal and not wood ashes, since a.) you don’t know the alkalinity of your ash and it may not work, and b.) your masa won’t taste like a fireplace. Once the kernels have soaked you’ll want to pinch off the pericarps (skins) and then grind/mash the starch while it’s still wet.

      Regarding blue corn, that’s actually a variety of corn that grows blue on the ear. It’s pretty neat looking stuff, but odds are you’ll never find dried blue corn kernels for masa…but you can always try!

      Let me know how the project goes!

      – Joe

    1. Great question! I’ll answer that on the blog if that’s OK. Have a look at the main window a little later today.

      – Joe

      1. No need to look it up. The nixtamalization process frees up niacin so that your body can absorb it. If you tried to live on a corn-beans-squash and some meat when you can get it (much like many of the ancient natives) diet without nixtamalization, you’d get a disease called pellagra as a result of the niacin deficiency. It probably destroys a few nutritional items too, but if corn is your staple with no other sources of niacin, the trade off is more than worth it.

        FWIW, I planted painted mountain corn and some Navajo Blue corn this year, and I’m interested on seeing what the hominy from those two varieties taste like. I can get blue corn hominy in the stores, but it’s pricey.

        1. Check back in and let me know what comes up, Jesse! I’ll be curious.

          – Joe

    1. Hey Dawn!

      It doesn’t have anything like baking powder in it, no. It’s just ready to be made into tamales, tortillas and what have you. Fresh masa is a lot better if you live near a large Mexican population, you can find it in tubs in the refrigerated section of a Mexican grocery store. Sadly Louisville doesn’t have enough Mexicans for that yet (hopefully soon we will), but in the meantime Maseca is good enough for me!


      – Joe

      1. Hi Joe! I just stumbled across your blog. I also live in Louisville and I’m looking for Masa Herina for a chili recipe. The only thing I can find is Masaca. It that the same? Will it give it the distinct flavor that masa herina does? Do you know where I can get it here? I only need like 2 tablespoons, but they really make the recipe!

        1. Hey Julie!

          Yes the best we can do at the moment is the dry Maseca masa mix. As you’ve probably discovered it can be found at the value market in Iroquoi Park and at many of those shops along Preston. If all you need is a little it will work fine.

          Soon I hope we’ll gain enough Mexicans that someone will open a tortilla bakery. At that point there’ll likely be fresh masa for sale around town. I look forward to the day!


          – Joe

  2. Hi I was wondering…..I’m wanting to make polenta, cornbread, and tamales, traditionally made, soaked first in lime water. I’ll be getting organic white dent corn and yellow (field?) corn here soon. Dent corn I guess is what my Komo grain mill is saying to use. So, my question is this; would I be able to grind the corn, soak it in lime water, and use that for all three above recipes? I could see how it would work for polenta and cornbread but not sure about tamales based off of what I’ve read…I have a large mortar and pestle, so if it’s just as easy as soaking the whole kernel, then grinding it that way, then great. I’m just wondering if it would be possible to grind it first, then soak. That would surely be more time saving anyways. I’m also a little mixed up in regards to the grinding process/end result… I’m thinking what my Komo will produce is corn meal/flour, but then if I soak it its masa harina. I’m not sure if there is a texture difference between them, or if it’s simply the preparation that changes it from corn meal to masa harina. Thanks for your time!


    1. That would be one heck of a project, Jamie! But if you’re up for the challenge I’d be interested to hear how it turns out. To get the right consistency for masa you’ll need a lot more leverage than a mortar and pestle can provide. In Mexico they use a flat device with a stone roller called a molcajete. Then of course hyou’ll need to make sure your chemistry is right. I’ve seen some resources online for people wanting to do it themselves. Have a look around and let me know what you come up with since I’ll be interested to hear the results of the experiment!


      – Joe

  3. Hi Joe, I’m hoping you can answer a question for me. I live in Europe and have been craving tacos. I found corn flour (not corn meal), and I’m wondering what is the difference between this and masa harina, or is it the same thing? Essentially, can I use corn flour to make a tortilla?

    Brooklyn Munch

    1. Hey Corinne!

      I wish I could tell you they were the same thing, but they are not. Corn masa is more like corn meal, though it has been subjected to an extra step called nixtamalization, which you probably already know about. Corn flour is a much more refined product that has its uses, but not for tortilla making. Sorry about that! On the upside, they’ll taste that much better when you get back here!


      – Joe

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