At the base of the brick staircase on the hillside south of the Van Cortlandt House you will see a large round grey stone embedded in the ground with patterned grooves and a hole in its center. This is a millstone that was removed from the historic Van Cortlandt gristmill, where grains such as wheat and corn were ground into flour or cornmeal. The Van Cortlandt gristmill was built in the early 1700s and stood at the southern end of Van Cortlandt Lake (see Mill Site). The 18th century gristmill was a sophisticated piece of machinery and the result of centuries of technological developments. Therefore, it required the supervision of a skilled miller to operate and maintain it. At Van Cortlandt Plantation, an enslaved African man named Piero worked as the miller.
It was the job of Piero the miller to regulate the flow of water from the mill pond by controlling a gate at the mill building. The water flow would propel a vertical waterwheel, forcing it to rotate. The water wheel rotated a shaft, which in turn caused the runner stone such as this one to spin on top of a stationary stone known as the bedstone. The miller poured grains into the hole in the center of the runner stone and the grooves in the stones scissored to cut the grains to make flour. The grooves pushed the flour out from the center where it could be collected at the end of a chute.
Piero the miller would also have to deal with neighboring farmers and enslaved Africans that brought grain to the mill for processing. He would determine how much to charge them for milling services and could have done some accounting as part of the business.
In addition to operating the mill, the miller would have to maintain it. This entailed periodically taking the millstones apart to resharpen the grooves. This process is known as “dressing” the millstones. This was done using hand carving tools and needed to be performed precisely to ensure a quality product. Then the stones would need to be repositioned. This involved setting the runner stone less than the width of a seed apart from the bedstone but without letting the two stones touch. Removing the stones from the mechanism and repositioning them was no easy task as they weighed over 1,000 pounds. Piero very likely learned this craft in his youth as an enslaved apprentice to a miller.