A liquid dispenser comprise a nozzle comprising an inlet in fluid communication with an outlet to form a flow path, a thermistor in fluid communication with the inlet, an actuator rod comprising a gasket rod tip viton, at least one centering pin to center the actuator rod in at least a portion of the flow path, a flowmeter in fluid communication with the inlet, a double acting pneumatic cylinder comprising a first pneumatic inlet and a second pneumatic inlet operatively connected to the actuator rod, and a switch lever operatively coupled to a micro switch, wherein the nozzle opens when gas enters the first pneumatic inlet when the switch lever is activated by pressing on the micro switch and closes when gas enters the second pneumatic inlet when the switch lever is deactivated. Portable and non-portable liquid dispensing systems comprising the liquid dispenser are also described.