Question

why did price of food grains rise old regime​

Answer 1

Between 1715 to 1789, the French population rose from about 23 million to 28 million. This led to a rapid increase in the demand for foodgrains but the production of grains could not keep pace with the growing demand. So the price of bread which was the staple diet of the majority rose rapidly.

Answer 2

The price of food grains rose in Old Regime because there was a rapid increase in the population and demand for food grains, but the production of food grains could not keep pace with the rising demand.