The modified test protocol consists in a single phase procedure:the fuel load is batch fed at the beginning. Time is counted when the pot is posed on fire. The test ends when all the fuel is consumed. The ebullition time refers to the moment when water temperature reaches the maximum temperature. All other outputs of the original WBT protocol are calculated on the total testing time. All tests were performed boiling 3 l of water in identical cast iron pots without lids (mass = 1.04 kg).