From dhcafe IG:
許多人誤解咖啡的苦味,認為那只是烘焙過度的結果。但其實, 咖啡的苦,更像是一棟從地基到屋頂層層鋪陳的建築。它由各種風味分子構築而成,每一層都有其結構功能與風格表現。如果我們能從宏觀到微觀去感受,就能從舌尖與舌根之間傳來的苦味訊號中,辨識出這杯咖啡的苦,是設計得當,還是結構錯置。
咖啡的苦,其實從生豆階段就已存在。咖啡因是一種直接、尖銳、幾乎無法忽略的感官訊號,就像一棟建築選用的原材料,從一開始就決定了整體的風格走向。**綠原酸(Chlorogenic acids) **則更像是原始的結構鋼材,未經加工時僅有輕微的澀與苦,卻會在烘焙過程中經由熱裂解、重組與排列,轉化為更深沉的風味基礎。當它被適當加熱,它就如彎折與定位過的鋼骨,成為支撐整棟咖啡風味建築的核心框架;若處理不當,它也可能埋下整體風味失衡的隱憂。
真正的工程,從烘焙開始。當溫度升高,綠原酸開始轉化為喹啉類(Quinides),這些分子賦予咖啡一種藥草般的苦感與清涼調性,像是垂直鋼構打下的柱腳,穩固而低調,支撐整體苦味結構的下層。它們不一定討喜,但若缺乏這一層,就如建築失去基礎支撐,容易空洞脆弱。
隨著烘焙進入深層階段,綠原酸會進一步裂解,生成苯基吲哚 (Phenylindanes),這是咖啡中最具「骨感」的苦味來源。它們彷彿構成鋼骨架間的橫向樑與對角撐桿,穩定地交織成堅固的骨架系統,並將前述的喹啉苦味明確框定在味覺結構中。這類苦味常集中於舌根與喉部,具有黏附性與延續性,就像一根埋得深的基樁,安靜卻存在感強烈。
到了風味建築的中段,我們會感受到**黑褐素(Melanoidins) ** 的登場。這些經由 Maillard 反應生成的大分子,如同灌漿的樓板與牆體,提供空間厚度與支撐質量。不僅帶來甜中帶苦的層次感,還能產生鹹感與回韻,使整體風味不再僅有骨架,而是有實感、有重量的品飲體驗。
若烘焙溫度控制不當、時間過長,風味外觀就會被**吡嗪類 (Pyrazines) **覆蓋——這些焦香苦味如同外牆清水模的表層處理,適當時能提供堅果、可可等熟香,替建築加上質感與設計語彙。但過量時,它們會覆蓋原有結構,讓所有層次都被煙燻味與碳化感所掩蓋,像是油漆太厚,掩蓋了原本的設計細節,反而成為一種負擔。
真正讓這棟「苦味建築」具有人性與可親感的,是最後的細節收尾。**內酯類(Lactones) **是在中深焙時出現的分子,它們柔和、帶有奶油與可可脂的口感,為鋼骨與水泥之間填補上柔性與緩衝,如同木地板、間接光源與溫暖牆色,讓整體空間從堅硬轉向溫潤,也讓苦味變得可飲、可親,甚至令人回味。
咖啡的苦,不再是單一的錯誤或過頭,而是從原材到結構設計的結果。它是一座味覺建築,內含地基、骨架、樓層、外牆與室內裝修,彼此連動,缺一不可。若能讀懂這些層次,就能辨識出哪種苦是穩固的基礎,哪種苦是過度的裝飾;也才能烘出那種苦得恰到好處、苦得令人感動、苦得有故事的好咖啡。
Rozali coffee:
Most of the CGAs are destroyed during roasting (hydrolysis), which varies depending on the roasting temperature and its genetic composition. The CGA’s losses are estimated to be approximately 45-54% in the light roast (Moon, Yoo, & Shibamoto, 2009), 60% in medium roast and 100% in the dark roast (Michael N. Clifford, 1979; Trugo & Macrae, 1984).
The CGAs break down to form caffeic and quinic acid. Studies show that CGA’s by-products such as 6 lactones of the mono-hydroxycinnamoyl-quinic acids are assumed to contribute to the bitter taste of roasted coffee (Ginz, 2001) and the 3 di-hydroxycinnamoyl-quinides are supposed to modulate the effect of caffeine (Martin et al., 2001). Moreover, the free quinic acids decompose further to form phenols like hydroquinone. However, little is known about the caffeic acid. The minor part degrades to simple phenols and the rest is assumed to be incorporated into the melanoidins.
Reference
....debunk a commonplace misconception regarding the perception of taste: the so-called “taste map”.
The custom of depicting the tongue as divided into four precise areas, where the sensitivity of the four basic tastes is more marked (sweetness at the tip of the tongue, sourness and saltiness at the sides and the bitterness at the terminal part) is now considered obsolete.
Actually, the taste buds do not focus sensitivity on any one taste, but we are able to perceive the basic tastes on the whole surface of the tongue because the fibers in the individual papillae provide a multi-faceted response to many different stimuli.
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