How does a percolator know when to stop perking?

A percolator stops perking when the brewed coffee reaches the desired strength, which is typically determined by the temperature and the time the water circulates through the coffee grounds. As the water heats up, it rises through a tube and drips over the coffee grounds, extracting flavors. Once the water reaches a certain temperature, it begins to cycle back down, and the brewing process continues until the desired brew strength is achieved. Some percolators have built-in timers or sensors that signal when to stop, while others rely on the user to monitor the brewing process.