紅茶冷了變混濁,可以喝嗎?

為什麼紅茶冷卻會變得混濁? 是雜質嗎?

有時候經過一段時間之後,原本清澈透亮的紅茶會變得有些混濁,而這個現象就稱為冷後渾。紅茶經過發酵之後,擁有豐富的茶黃質茶紅質,一般來說,茶黃質茶紅質含量越多,紅茶茶湯則越明亮。會產生冷後渾的原因是因為原本茶中的茶黃質茶紅質咖啡因,經過熱水沖泡後,會呈現游離的狀態而溶解在茶湯中,而當茶湯經過冷卻,溫度降低之後,反而會促使茶黃質茶紅質咖啡因互相聚集結合而產生聚合物,造成淺褐色的乳狀物質沉澱,使得原本清澈的紅茶變得混濁[1-4]。

通常茶黃質茶紅質含量越高,越容易產生冷後渾,而有時候綠茶烏龍茶中的兒茶素也會與咖啡因結合而產生混濁的現象[4]。雖然冷卻後的紅茶有些混濁,不過經過加熱、溫度再次上升之後,茶湯則又會恢復原本清澈透亮的樣子。另外,在紅茶沖泡後馬上加入冰塊降溫,也可以避免聚合物的沉澱而造成茶湯混濁[1-4]。

紅茶的冷後渾是因為紅茶中豐富的茶黃質茶紅質咖啡因聚合沉澱的自然現象,而茶黃質茶紅質也是相當有益身體健康,因此下次再看到混濁的紅茶可千萬別驚訝,也不要認為是因為紅茶品質不佳所造成的哦!

 

-Research team @ 茶水部 LittoTea, 澄萃茶藝.

 

The phenomenon of cream down

Sometimes you would find the phenomenon that black tea turns pellucid into turbid after a while, which is called cream down. Black tea with the full ferment contains rich theaflavin and thearubigins. The more theaflavin and thearubigins black tea contains, the brighter red it is. The reason why cream down emerges is related to the temperature. When we use hot water to brew tea, theaflavin, thearubigins and caffeine are usually free in the high temperature. However, in the process of cooling down, theaflavin and thearubigins would start to combine with caffeine to produce polymer in the lower temperature. Therefore, the brown milky substance accumulates to turn pure black tea into turbid one[1-4].

It is believed that cream down is usually accompanied by black tea containing more theaflavin and thearubigins. Sometimes catechin in green tea and oolong tea would combine with caffeine to make tea turbid as well[4]. Turbid black tea could turn pellucid by heating again. In addition, adding ice into black tea immediately after brewing also reduces the accumulation of polymer to make tea turbid[1-4].

Cream down is a natural phenomenon not caused by the poor quality of black tea but caused by the polymerization of theaflavin, thearubigins and caffeine in black tea. Theaflavin and thearubigins even benefits health a lot. Therefore, don’t be too surprised when you see turbid black tea next time!

 

-Research team @ 茶水部 LittoTea, 澄萃茶藝.

 

Reference

[1]http://ajimylive.pixnet.net/blog/post/164755851-%E3%80%90%E7%9F%A5%E8%AD%98%E3%80%91%E7%B4%85%E8%8C%B6%E9%AB%98%E5%93%81%E8%B3%AA%E8%B1%A1%E5%BE%B5—%E5%86%B7%E5%BE%8C%E6%B8%BE

[2]https://read01.com/MRQ8mR.html

[3]https://read01.com/2dB3A4.html

[4]https://read01.com/M2k6Da.html

Lynn Chiang

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