The more times the lid is lifted, the more bitter the tengjue will turn out to be. Wugus cultivator Cheng Shu-hsing, meanwhile, is a master chef when it comes to this food. He says that in preparing wugus one cannot slice the plants with a knife, but rather should tear them by hand, in order to preserve nutitional value and moistness.
種山蘇的鄭書杏則是山蘇料理高手，他說，料理山蘇時不能用刀切，必須用手折，才不會破壞維管束和細胞組織，保持營養和水份，口感才會鮮嫩。