It was standard practice to scald cornmeal as the first step in American bread recipes that used cornmeal throughout most of the 19th century. Based on the extensive number of 19th century references to this method I think it is reasonable to impute the system back to the early use of cornmeal in the 17th century. Cornmeal can taste bitter. The scalding hot water converts some of the starches to sugar. It also softens the meal prior to baking, as boiling beans soften beans prior to cooking. As bitter was not (and is not) a desirable flavor in English cooking, using boiling water to counteract this sometime fault of cornmeal will have been a bread making step that the early settlers were familiar with. Gervase Markham, in his influential 1614 cookbook, the English Housewife, suggests pouring boiling water over pea flour to counteract its otherwise “rank” smell.

Parmentier wrote about Southern French cornbreads in the 1820s. He also included this boiling water step. There are American cornbreads that were leavened with yeast. Parmentier, of course, records the French use of levain as their cornbread leavening of choice. Scalding is a procedure one also sometimes finds used with rye breads. The great French anthropologist, Marcel Maget, documented the use of boiling water in the rye breads of the French Alps, most notably, in his documentation of the pain bouilli in the French village, Villar’ d’Arene. The Villar D’Arene rye made with the boiling water has a sweet tonality, and contrasts with the sour tonality of the rye bread made in the neighboring village of Le Chazelet in which the rye bread is made with a different mixing method, one that brings out sour, rather than sweet tonalities. That helps highlight and the importance of the shift in taste that scalding corn and rye and tails.

The scalding method is simple, if heating water in a kettle, then let the water come off the boil and then, holding the kettle at shoulder height, pour onto the corn or rye flour, or, as in many 19th century American breads, over a mix of both corn and rye. Mix with something other than ones hands! I always cover the bowl with a towel, and sometimes even wrap the bowl in a blanket so as to slow down the cooling process in an effort to maximize the conversion of starches to sugars.

The American cornmeal cuisine included “hasty puddings” which we can think of as polenta. There was a continuum in some senses between the cornmeal porridge dishes, pancakes, griddle breads, and cornmeal loaf breads. That cornmeal shifts to sweet when prepared with hot water will have been one of its attractions, and one of the reasons that corn was immediately accepted as a useful secondary bread grain and why cornbreads remain a bread in contemporary American culinary culture — though now sweetness is almost always added with sugar — though it is important to acknowledge that sugar as a cornbread ingredient is vehemently opposed by at least some Southern cornbread consumers.

The sweetness that boiling water brought to cornmeal was often amplified through the addition of molasses. Molasses, which came to New England through their part in the trade of enslaved Africans to the Caribbean is slightly sweet, nutritious, and blends nicely with breads that include cornmeal and rye.

The following text is from Lydia Child’s influential Frugal Housewife of 1840. Her Indian Cake head note gives a sense of the improvisational way in which women in the 1840s approached this bread. Child refers to it is a “cake.” This is cake in the sense of being relatively flat rather than in the sense of a dessert bread. In the context of bread, cake is the opposite of loaf.

The formal recipe calls for milk rather than water. In the general description the water is specified as “scalding water.” There are many 19th century American bread recipes that call for scalding milk. A good copy editor would have caught the inconsistency of calling for scalding water in the the introductory narrative but not in the formal recipe. Besides scalding milk to use it hot, milk was often scalded as a matter of course before using it in cooking. In this case, mix the Indian meal specified in the recipe with scalding hot milk. I always cover doughs I make with scalding water or milk and often even wrap the bowl with a towel to slow down the cooling. I do this to give the het time to convert starches to sugars and to more fully hydrate the flour before baking.

The baking method Child for in this recipe is baking in a “bake-kettle.” A “bake-kettle” was the New England terminology at this time for what is now called a “Dutch oven.”.In my experiments with using Dutch ovens I have concluded that the interior temperature was usually around 350F (180C), so if you are baking in your kitchen oven, then bake it at 350F. Regarding hearth cooking technique, often, when baking in Dutch oven, the Dutch oven or bake-kettle was placed in front the fire and embers were shoveled under the oven, and sometimes also on top. In this case, Child calls for pre-heating the oven so the batter is put into an oven that is hot, but it does not seem that coals are shoveled underneath. If you like your cornbread browned on the top, then after it is baked shovel a load of embers on the top of the Dutch oven, or if baking in your oven, slip it under a broiler.

INDIAN CAKE.
Indian cake, or bannock, is sweet and cheap food. One quart of sifted meal, two great spoonfuls of molasses, two tea-spoonfuls of salt, a bit of shortening half as big as a hen’s egg, stirred together; make it pretty moist with scalding water, put it into a well greased pan, smooth over the surface with a spoon, and bake it brown on both sides, before a quick fire. A little stewed pumpkin, scalded with the meal, improves the cake. Bannock split and dipped in butter makes very nice toast. A richer Indian cake may be made by stirring one egg to a half pint of milk, sweetened with two great spoonfuls of molasses; a little ginger, or cinnamon; Indian stirred in till it is just about thick enough to pour. Spider or bake-kettle well greased; cake poured in, covered up, baked half an hour, or three quarters, according to the thickness of the cake. If you have sour milk, or butter-milk, it is very nice for this kind of cake; the acidity corrected by a tea-spoonful of dissolved pearlash. It is a rule never to use pearlash for Indian, unless to correct the sourness of milk; it injures the flavor of the meal.

Nice suet improves all kinds of Indian cakes very much.

Two cups of Indian meal, one table-spoonful molasses, two cups milk, a little salt, a handful flour, a little saleratus, mixed up thin, and poured into a buttered bake-kettle, hung over the fire uncovered, until you can bear your finger upon it, and then set down before the fire. Bake half an hour.

Because mixing cornmeal with scalding water or milk as such standard practice even through to the end of the 19th century, you should probably always use water just off the boil even when the recipe does not explicitly call for that method.