Brandywine Mills in the Revolutionary War

During the Revolutionary War the Tatnall and Lea flour mills furnished flour to the American army. Washington and Lafayette visited Joseph Tatnall.  Before the battle of the Brandywine, Washington ordered the top grinding stones of the mills to be removed and hidden from the British troops.

"These mills were an important factor in furnishing to the American army, during the Revolution, the staff of life. No mills of such importance existed in the colonies at that time. When the British landed at the head of Elk in 1777, having in view the invasion of Philadelphia, Washington ordered the dismantling of the Brandywine Mills to prevent the possibility of them falling into the hands of the British. The mill-stones were thrown out of gear and some of them taken several miles away and secreted."

Conrad, Henry Clay.  History of the State of Delaware, vol. 2    1908

 
"During the period of the Revolutionary War, the owners of these mills, through Robert Morris, Washington’s financier, supplied very considerable quantities of flour and meal to the patriot troops encamped at various times in this region. Shortly before the memorable battle of the Brandywine, Washington ordered the dismantling of several mills in Northern Delaware and contiguous portions of Pennsylvania for fear that they might fall into the hands of the British, whom it was apprehended would cross the Brandywine in the vicinity of Wilmington, and be operated by them for the sustenance of their army. These mills were among them. The order, signed by Washington, and cautioning the utmost haste and great secrecy in the removal of the “running” or upper stones to a safe distance, is still preserved. The work was duly accomplished. Soldiers, coming with wagons to the Brandywine, conveyed them to Chester County, Pennsylvania. After safety had been assured, Thomas Lea was sent to ask a return of the stones, and Washington, although signifying his willingness, neglected, amid the hurry and confusion of the time, to give an order. They were ultimately recovered, for by the order of the great commander himself, they had been marked to distinguish them from others taken at the same time.
It was during the Revolution that wheat and flour brought the highest (apparent) prices ever known in the history of milling. The old books at the Brandywine Mills show that in 1780 wheat was bought at twenty-four dollars a bushel, and that some three or four hundred barrels of flour were sold for the gross sum of twenty-one thousand pounds. It is unnecessary to say that the currency was somewhat inflated at that period.