I once toured a microbrewery which produces beers the same way they did in colonial times. This involved pumping the water up ~20 feet into a copper kettle sit

I once toured a microbrewery which produces beers the same way they did in colonial times. This involved pumping the water up ~20 feet into a copper kettle situated above an elevated brick furnace. The water was boiled, then gravity fed down canals via ladles to other kettles for mashing and lautering. Now, this brewery was replicating 19th century American brewing, but these ideas probably came from Europe. How else are they going to get water to a specific temperature before the invention of thermometers?