Evidently, he had relaxed too soon. He picked up the lemon, squeezing exactly thirteen drops. To his horror, his cauldron started sparking immediately. Before Harry could of reacting, the liquid boiled up — quite like milk — but thankfully it went back to simmering after a few seconds. Smoke began rising from the cauldron, alight with a million sparks. A sugary scent spread from the sparking smoke. Yet again, Harry had no idea what could have caused that effect.