For much of the 19th century, American breads, were often made with cornmeal and If you can get a bread dough into the gelatinizing temperature range appropriate a given bread grain — in the 19th century American context, rye, and corn — gelatinizes multiple changes will take place altering the taste and texture of the bread you make with the gelatinized flour.
Gelatinizing all, or part of a dough, has been a practice known to bread making since ancient times. We know from the analysis of ancient Egyptian tomb breads that gelatinization was one component of Egyptian bread making technique for selected breads. In the case of Egyptian emmer breads, gelatinization increased dough extensibility.
The contemporary Japanese bread making technique utilizing tangzhong in the milk bread style of bread, basically, adding some roux to the dough, is an example of making a wheat bread with gelatinized dough. In the case of the Japanese practice, the tangzhong softens the crumb.
The French rye bread, Pain Bouilli, a dough made with water just off the boil, uses gelatinization for the same purpose 19th century American bakers used it in their corn and rye breads — to convert dough starches to sugars. With respect to cornbread, as gelatinizing cooks the grain, softening it, this makes it possible to make very basic cornbreads using minimal baking techniques, even with coarse cornmeals. The common Jonny Cake was often a cake, a flattened piece of dough, that was baked in ashes or that was baked on a griddle. The gelatinized dough produces a baked product that has a soft crumb and a taste that is either neutral or sweet. The hard coarseness of the meal is resolved through gelatinization as is the problem that undercooked cornmeal can taste bitter.
Corn gelatinizes at 144–162°F (62–72°C), while rye gelatinizes at 124–140°F (51–60°C). To gelatinize dough, mix the flour with water that is just off the boil, or scalded milk (milk that is just brought to the boil. The dough is too hot to touch, so mix with a wooden spoon.
The reactions that produce the most conversion of starches to sugars take time to complete. The longer you can keep the dough within the gelatinizing range the sweeter that final bread will be. I suggest keeping the dough in an oven set at around 150 F for two hours or wrapping the bowl in a blanket or down jacket. The larger the batch of dough you make the more stable its temperature will be.
Scalding hot water instantly gelatinizes the flour. In the presence of scalding water the starch grains imbibe so much water that they rupture, releasing glucose. You will find that normal dough hydration numbers, like 60% for a sandwich bread, 80% for an open crumb sourdough loaf, and 90% for ciabatta are all insufficient for most gelatinized bread doughs.
As you add water you will immediately see the difference between adding scalding hot water to dough and adding the cool to warm water we usually use to mix dough.
Rye & Cornmeal Blend: For a bread made with half cornmeal and half rye, a common bread type in New England for much for a large swath of the 19th century, I’d start with 125% water by weight of flour. Thus, if your flour weighs, say, 500g, a little more than a pound, then add water weighing 25% more — 125g — for a total of 625g water. As it is essential to getting a changed taste profile out of gelatinized dough to be able to hold the dough at gelatinizing temperatures — you want to make the dough as hot as possible as quickly as possible. Flour will clump as you pour on the water. You may find starting mixing with a whisk or in a mixer is helpful.
Cornmeal, only. Cormeal absorbs more water than rye. In bakers math, the water should be around 150% of the weight of the flour. Thus, 500g flour calls for 750g water ((500+(500*.5)). Coarse cornmeal takes much longer than fine cornmeal to absorb water so the length of time cornmeal hydrates before baking is an area of control over the taste and mouthfeel of the finished product.
As soon as your dough is mixed, wrap the dough in a blanket, a down jacket, or put into an oven set to 150F, 65C. The ideal for maximum glucose release from the starch grains into the dough will take place if you can hold the dough for two hours at the hot temperature.
There are no instructions in 19th century texts about maximizing the period the dough is hot. This was either not noted or it was assumed you knew to keep the dough warm by, for example, placing the dough in a covered bowl in front of the fire. The French bread I mentioned earlier, pain bouilli, was mixed in very large batches. The dough was mixed in large dough troughs with hundreds of pounds of flour and water. The troughs were covered and the room in which they sat was heated with a wood stove to warm the room as the breads was traditionally made at the end of November. The taste profile of pain bouilli was sweet even thought it was naturally leavened just by letting the hot dough sit for roughly 12 hours. American bread bakers would never ever in a thousand years have let their dough sit for 12 hours as they were terrified of what the imagined the negative health consequences should be of eating a bread that had even a hint of the sour taste.
When corn and rye were made into a bread the water or milk — and milk was often used in rye breads — was always at the boil or scald. If a bread was a mix of wheat and corn — wheat and Indian in the language of the period cookbooks — then the cornmeal was prepared with hot water with the wheat and yeast added to the cornmeal after it had become lukewarm. Wheat rye mixes, common in Europe, was not common in 19th centuryAmerica. Their first choice for adding to wheat flour was cornmeal. It makes a delicious bread.