Heirloom grains are typically defined as varieties that were developed before WWII, and have had limited breeding selection since. After World War II, the U.S. had excess capacity to produce large amounts of ammonia cheaply, since it was no longer needed for making explosives. Agriculture then starting using this ammonia to add extra nitrogen to the soil for raising crops.
For many crops, nitrogen in the soil is the limiting nutrient for growth. Now for the first time in history, farmers had access to an affordable source of plant available nitrogen they could apply to the ground. The “Green Revolution” that occurred after WWII was accomplished by maintaining higher than natural nitrogen concentrations in the soils and developing crop varieties that could better utilize the higher ammonia levels and yield more per acre. Many traits were changed in our modern crops to make them tolerate these unnaturally high soil nitrogen levels. Some intentionally and some inadvertently.
At the same time, the U.S. population was becoming mostly urban, and farms changed from growing food for themselves to growing “cash” crops which were sold to this growing urban population. Yield and profit became the most desirable traits in the new varieties, with nutrition and taste hardly ever being considered.
Most of the great tasting, nutritious old varieties fell out of use because they couldn’t generate as much profit per acre.
Heirloom grains sold by us include:
(using the pre-WWII definition)
Blue Hopi corn
Bloody Butcher corn
Henry Moore corn
Turkey Red hard wheat
Pennsylvania Dutch Butter Flavored popcorn
*I’m unsure of the heritage of these varieties. In general, relatively little breeding has been done in either common oats (Avena sativa) or buckwheat. Even less breeding has been done in hulless oats (Avena nuda) since WWII and some consider them ancient grains.