Guoba (rice crust)

「鍋巴」 (guoba; 「グオバー」 in Japanese transcription, also 「飯焦」 (faan ziu) in Cantonese) is the layer of scorched rice that forms on the bottom of a pot during cooking and is also eaten on its own as a snack. The Chinese dictionary 「漢典」 (in translation: "Dictionary of Chinese Characters") defines it as 「燜飯時緊貼鍋底燒焦的飯層」 (in translation: "the layer of scorched rice adhering to the bottom of the pot when rice is cooked") and states that it is usually pale yellow or black. This definition itself contains no evaluative terms for taste or smell, such as bitterness or a toasted aroma.

An independent food-media article discusses the quality of the scorching in more detail. An article by an individual food writer states 「『焦』の字はあるが、キッチンを焦がすような黒炭の焦げではなく、金色に香ばしい焦げであり、香りであって苦味ではない」 (in translation: "although the name contains the character meaning scorched, this is not the black, charcoal-like scorching of a burned kitchen, but golden, aromatic browning: aroma, not bitterness"). It clearly distinguishes ideal guoba browning from accidental blackening. The explicit assessment 「苦味ではない」 (in translation: "not bitterness") is also notable here. However, this is an individual food writer's account, without scholarly verification such as assessment by a sensory panel.

A food-science paper reports that the characteristic aroma of 「黄大茶」 (huangdacha), a type of Chinese post-fermented tea, is called 「锅巴香（鍋巴の香り）」 (in translation: "guoba aroma"), and that its main aroma-active substances are 5 pyrazines with 「烘烤香」 (a roasted aroma). However, this study did not directly assess guoba through sensory evaluation; it mentions guoba only as a comparison for the tea's aroma. This account has also been checked only at abstract level and contains no sensory data on bitterness in guoba itself.