Outside the north wall of Mission San José, next to the acequia that supplies its power, stands a gristmill. Built around 1794, this mill was the only water-powered mill in the area during the Spanish colonial period. It was not until the end of the mission period in Texas that the Indian neophytes accepted wheat-based products; they move from corn to wheat in their diets. Farmlands were open to its cultivation and a mill was constructed. However, the mill constructed to process this wheat had a short life.
How the mill works
A wood and metal shaft attached to the water wheel extends up through the floor of the milling room and the bottom millstone. The top stone is then balanced on a metal spike on the end of the shaft. As the water wheel turns, the top stone turns;the bottom one remains stationary. One revolution of the wheel equals one revolution of the top stone. The miller has the ability to raise or lower the top stone to adjust for coarser or finer flour. But at no time should the two millstones touch –the friction could render the flour unusable or cause a fire!
How wheat is ground
Grooves, or furrows, carved in both stones, push the grain to the outer edge of the stones. The furrows are deep and wide in the center and become shallow and narrow at the outer edge of the stones. In addition to them being tapered, the furrows of the top stone crosses the ones in the bottom stone like scissors or shears. By the time the wheat has reached the outside edge of the stones it is wheat meal and can be as fine as face powder. The meal is collected in a box or buckets below the meal spout and then would be sifted to create flour.
Even though the San José mill was small and simple, when operating at full capacity, it could grind one bushel, or 60 pounds, of grain every hour. This was enough flour for 1,000 loaves of bread in one day. Why the mill ceased operation within 10-12 years is a mystery.
Last updated: August 11, 2015