Black tea - Wikipedia

Step 1

After the harvest, the leaves are first withered by blowing air on them.Then black teas are processed in either of two ways, CTC (crush, tear, curl) or orthodox. The CTC method produces leaves of fannings or dust grades that are commonly used in tea bags but also produces higher (broken leaf) grades such as BOP CTC and GFBOP CTC (see gradings below for more details). This method is efficient and effective for producing a better quality product from medium and lower quality leaves of consistently dark color. Orthodox processing is done either by machines or by hand. Hand processing is used for high quality teas. While the methods employed in orthodox processing differ by tea type, this style of processing results in the high quality loose tea sought by many connoisseurs. The tea leaves are allowed to completely oxidize.[10]OrthodoxThe withered tea leaves are heavily rolled either by hand or mechanically through the use of a cylindrical rolling table or a rotovane. The rolling table consists of a ridged table-top moving in an eccentric manner to a large hopper of tea leaves, in which the leaves are pressed down onto the table-top. The process produces a mixture of whole and broken leaves and particles which are then sorted, oxidized and dried. The rotorvane (rotovane), created by Ian McTear in 1957 can be used to replicate the orthodox process.[10] The rotovane consisted of an auger pushing withered tea leaves through a vane cylinder which crushes and evenly cuts the leaves, however the process is more recently superseded by the boruah continuous roller, which consists of an oscillating conical roller around the inside of a ridged cylinder.[10] The rotorvane can consistently duplicate broken orthodox processed black tea of even sized broken leaves, however it cannot produce whole leaf black tea.[11] The broken leaves and particles from the orthodox method can feed into the CTC method for further processing into fanning or dust grade teas."Cut (or crush), tear, curl" (CTC)A production method developed by William McKercher in 1930. It is considered by some[who?] as a significantly improved method of producing black tea through the mincing of withered tea leaves.[12] The use of a rotovane to precut the withered tea is a common preprocessing method prior to feeding into the CTC.[10] CTC machines then further shred the leaves from the rotovane by passing them through several stages of contra-rotating rotors with surface patterns that cut and tear the leaves to very fine particles.[10]Next, the leaves are oxidized under controlled temperature and humidity. (This process is also called "fermentation", which is a misnomer since no actual fermentation takes place. Polyphenol oxidase is the enzyme active in the process.) The level of oxidation determines the type (or "color") of the tea; with fully oxidised becoming black tea, low oxidised becoming green tea, and partially oxidised making up the various levels of oolong tea.[13][14] This can be done on the floor in batches or on a conveyor bed with air flow for proper oxidation and temperature control. Since oxidation begins at the rolling stage itself, the time between these stages is also a crucial factor in the quality of the tea; however, fast processing of the tea leaves through continuous methods can effectively make this a separate step. The oxidation has an important effect on the taste of the end product,[14] but the amount of oxidation is not an indication of quality. Tea producers match oxidation levels to the teas they produce to give the desired end characteristics.Then the leaves are dried to arrest the oxidation process.Finally, the leaves are sorted into grades according to their sizes (whole leaf, brokens, fannings and dust), usually with the use of sieves. The tea could be further sub-graded according to other criteria.

Step 2

^ a b .mw-parser-output cite.citation{font-style:inherit}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .id-lock-free a,.mw-parser-output .citation .cs1-lock-free a{background:linear-gradient(transparent,transparent),url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited a,.mw-parser-output .id-lock-registration a,.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration a{background:linear-gradient(transparent,transparent),url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription a,.mw-parser-output .citation .cs1-lock-subscription a{background:linear-gradient(transparent,transparent),url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-ws-icon a{background:linear-gradient(transparent,transparent),url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-maint{display:none;color:#33aa33;margin-left:0.3em}.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}Heiss, Mary Lou; Heiss, Robert (2011). The Story of Tea: A Cultural History and Drinking Guide. Potter. ISBN 978-1607741725. ^ Nanien, Yuniar; Aria, Cindyara; Sri, Haryati (14 November 2019). "Important to learn about Indonesian tea diversity: Expert". en.antaranews.com. Antara News. Retrieved 15 October 2021. ^ Bressett, Ken. "Tea Money of China". International Primitive Money Society Newsletter (44, August 2001). ^ "21 Extensive and Complete information on Darjeeling Tea". thunderbolttea.com. Retrieved 29 April 2019. ^ "herbal Tea - Grades and Characteristics - Teabox". teabox.com. 15 March 2017. Retrieved 19 March 2018. ^ "Types of Tea & Different Tea Varieties in India – Assam, Darjeeling, Kangra & Nilgiri". Retrieved 13 December 2016. ^ "Hadong Jaeksul Cha". Slow Food Foundation. Retrieved 23 June 2017. ^ Richardson, Ben (6 April 2006). "Bergamot growers get whiff of success". BBC News. ^ "India, the largest black tea consumer in the world". Archived from the original on 6 February 2018. Retrieved 5 January 2018. ^ a b c d e Varnam, Alan H.; Sutherland, J. M. (1994), Beverages:Technology, Chemistry and Microbiology, Springer ^ Heiss, Mary Lou; Heiss, Robert J. (2007), The story of tea: a cultural history and drinking guide, Random House ^ Harbowy, Matthew E.; Balentine, Douglas A.; Davies, Alan P.; Cai, Ya (1997), "Tea Chemistry", Critical Reviews in Plant Sciences, 16 (5): 415–480, doi:10.1080/07352689709701956 ^ "Black Tea Oxidization". Tin Roof Teas. Retrieved 23 August 2016. ^ a b "Oxidation of Tea - RateTea". Retrieved 13 December 2016. ^ a b ISO3103, "ISO 3103". ^ Upton Tea Imports, "A Brief Guide to Tea" (PDF). Archived from the original (PDF) on 23 November 2006. Retrieved 21 October 2006. ^ a b c "Black tea: How effective is it?". MedlinePlus, US National Library of Medicine. 2015. Retrieved 15 March 2015. ^ a b Hartley L, Flowers N, Holmes J, Clarke A, Stranges S, Hooper L, Rees K (June 2013). "Green and black tea for the primary prevention of cardiovascular disease". Cochrane Database Syst Rev (Systematic Review and Meta-Analysis). 2013 (6): CD009934. doi:10.1002/14651858.CD009934.pub2. PMC 7433290. PMID 23780706. ^ Liu G, Mi XN, Zheng XX, Xu YL, Lu J, Huang XH (October 2014). "Effects of tea intake on blood pressure: a meta-analysis of randomised controlled trials". Br J Nutr (Meta-Analysis). 112 (7): 1043–54. doi:10.1017/S0007114514001731. PMID 25137341. ^ Shen L, Song LG, Ma H, Jin CN, Wang JA, Xiang MX (August 2012). "Tea consumption and risk of stroke: a dose-response meta-analysis of prospective studies". J Zhejiang Univ Sci B (Review). 13 (8): 652–62. doi:10.1631/jzus.B1201001. PMC 3411099. PMID 22843186. ^ Larsson SC (January 2014). "Coffee, tea, and cocoa and risk of stroke". Stroke (Review). 45 (1): 309–14. doi:10.1161/STROKEAHA.113.003131. PMID 24326448. ^ Wang W, Yang Y, Zhang W, Wu W (April 2014). "Association of tea consumption and the risk of oral cancer: a meta-analysis". Oral Oncol (Meta-Analysis). 50 (4): 276–81. doi:10.1016/j.oraloncology.2013.12.014. PMID 24389399. ^ Zheng J, Yang B, Huang T, Yu Y, Yang J, Li D (June 2011). "Green tea and black tea consumption and prostate cancer risk: an exploratory meta-analysis of observational studies". Nutr Cancer (Meta-Analysis). 63 (5): 663–72. doi:10.1080/01635581.2011.570895. PMID 21667398. S2CID 21567675. ^ Lin YW, Hu ZH, Wang X, Mao QQ, Qin J, Zheng XY, Xie LP (February 2014). "Tea consumption and prostate cancer: an updated meta-analysis". World J Surg Oncol (Meta-Analysis). 12: 38. doi:10.1186/1477-7819-12-38. PMC 3925323. PMID 24528523. ^ Giacomin, Caroline E.; Fischer, Peter (September 2021). "Black tea interfacial rheology and calcium carbonate". Physics of Fluids. 33 (9): 092105. Bibcode:2021PhFl...33i2105G. doi:10.1063/5.0059760. S2CID 239631952.

Step 3

^ Herbal teas are not made from Camellia sinensis and thus are not technically considered tea.