The number of olives that can be processed per hour varies by the capacity of the machine. In Corning, California, there is a machine that can pit 57,000 olives per minute (2004.)
Only green olives can be machine pitted — that’s because they are firm enough to be pitted. Black olives, which are softer, can’t be machine pitted, because the process would just squash them. The pitted black olives that North Americans buy aren’t actually black olives. They are olives that were harvested green so that they would be firm enough to be machine pitted, then turned black through oxidization in an aerated lye solution.
To pit your own olives at home: Spread olives out on a piece of paper towel. Put another piece of paper towel on top. Roll with a rolling pin to crush the olives, really pressing down. Remove the top layer of paper towel, sort through the olives and pick out the pits. If you don’t have a rolling pin, then put them on a cutting board and press down with the side of a wide knife, such as a cleaver or a chef’s knife, then pick the pits out. This will in effect give you broken pitted olives.
Alternatively, you can purchase an olive pitter and pit them one by one.
1 cup of pitted olives = 5 oz = 155g