Lime Water and Nixtamalization of Corn

KAL Dolomite Powder

By Cat, Nov 2014 (Photo, right, from Amazon)

Lime water has been used for centuries for soaking corn kernels or corn flour to make hominy or masa harina (or just masa), respectively, in a process known as nixtamalization (from the Aztec) (2). Lime water is alkaline, which frees-up the niacinamide (niacin or Vitamin B3) from being bound in the whole grain, making it available for absorption and preventing the niacin-deficiency disease known as pellagra in cultures whose diet is based on corn.

Note that lime water is NOT the juice of limes (fruit), but rather a liquid made by dissolving limed calcium (limestone or dolomite) in water. This is the same lime that you use in the garden to reduce the acidity of the soil; however, be sure to use food-grade dolomite for liming corn (not the lime you buy at a hardware store, as it may contain lead or other toxic heavy metals). Wood ash is an alternative to lime. Dolomite powder is used in the method detailed here, to produce lime water.

You can buy cornmeal that has already been limed; it is called masa harina, or just masa. This is far easier than doing the liming yourself. Liming the corn – as in masa – has benefits beyond improving the nutritional value of the corn. See below for details.

However, if you don’t use it up quickly, buy only small quantities of masa or regular cornmeal, because with time, the fragile oils in the corn will become rancid.

Benefits of liming corn

In addition to improving the nutritional value of the corn, treating it to a lime water soak as many practical benefits. From Wikipedia, on Nixtamalization (2):

• The corn is more easily ground;
• Its flavor and aroma are improved;
• Mycotoxins are reduced;
• The corn is softer (due to action of the alkaline water on a glue-like component of the maize cell walls, which also loosens the hulls from the kernels);
• Corn meal that has not been limed is unable, by itself, to form a dough (which is why wheat flour is included in modern cornbread recipes); the chemical changes that result from liming allow the masa to form a dough

Lime water, for soaking cornmeal

‘Lime’ is caustic, so be careful when handling it.

Mix up the lime water at least one day in advance of when you want to use it, to allow the calcium carbonate to dissolve in the water, and the remaining solids to settle.

These instructions, from Nourishing Traditions (1) make almost 2 quarts lime water:

1. Pour about 1-inch of dolomite powder* in a half-gallon jar (2-quart jar).
2. Fill jar with filtered water. Cover jar tightly and shake well.
3. Let stand overnight. The powder will settle, and the resultant clear liquid is lime water.
4. Store in a cool place until ready to use.
5. Carefully pour out needed amount for soaking cornmeal; see details, below.

* Alternately, use pickling lime (or ‘Cal‘ if purchased from a Mexican grocer), instead of dolomite powder; see the Nourishing Cook (3) for details. However, because pickling lime is more caustic than dolomite, you must wash the cornmeal with several changes of fresh water after the soak, to neutralize the alkalinity. Otherwise, the alkalinity will prohibit leavening, and/or prohibit the beneficial acidic pre-soak from being effective.

Using Lime Water to Nixtamalize Corn Flour

NOTE: this process is not needed when using masa harina, as it has already been nixtamalized.

The following is from a Nourishing Traditions recipe for corn bread (1).

• For 1 cup cornmeal you will need 3/4 cup lime water for the soak.
• Add lime water to the cornmeal and let soak about 7 hours before using in recipe.
• Following the limewater soak, you can do a traditional presoak of the cornmeal along with other flours or nuts in the recipe (using liquid whey, yogurt, buttermilk or citrus juice).

If you use cornmeal often, make up a large batch and store in a cool place (refrigeration is not necessary, just a cool cupboard or a root cellar).

References:

1. Nourishing Traditions, by Sally Fallon with Mary G. Enig, PhD (see Beloved Cookbooks for more information)
2. Wikipedia on Masa (en.wikipedia.org/wiki/Masa), Hominy (en.wikipedia.org/wiki/Hominy) and Nixtamalization (en.wikipedia.org/wiki/Nixtamalization)
3. The Nourishing Cook (thenourishingcook.com/how-to-make-lime-water-for-soaking-corn)