Tea Information

The New Tea Season and Its Odor of Freshness

“The new tea season is here, limited stock only!” and so just as spring comes to full bloom, one cannot miss seeing announcements of fresh tea arrivals sprouting everywhere from their favorite Japanese tea shops around the world. Japanese fresh spring tea, Shincha (jp. 新茶) is truly special. Anticipated by tea connoisseurs around the globe, Shincha is a seasonal delicacy, symbolizing the celebration of spring and the implication of treasuring a fleeting moment. While Shincha and Ichiban-cha (jp. 一番茶, “first flush”) are generally the same tea, a product labelled Shincha is packaged and sold immediately after harvesting and processing, highlighting the highly fresh, grassy and sweet notes, an experience one can indulge in around the month of May. But what exactly is the reason Shincha tastes this way?

Biochemically speaking, tea volatile compounds contribute to the aroma of the tea. Although those compounds are very fragile and comprise only about 0.01% to 0.03% of the tea leaf by weight, more than 630 components have been identified in the final flavor of tea so far[1] and luckily, our nose is capable of detecting even miniscule amounts of it. Japanese researchers have studied the green odor of tea since 1933[2]. In particular, they found that the fresh grassy notes come from a mixture of aromatic volatile 6-carbon and 9-carbon compounds, the former are commonly referred as “green leaf volatiles”. The most prominent among them is cis-3-Hexen-1-ol, also known as “leaf alcohol”, which is an oily liquid that has an intense smell of fresh cut grass or leaves[3]. While all teas contain some leaf alcohol, it is thought that the main contributor to the unique fresh aroma of Shincha is the green leaf volatile “cis-3-hexenyl-hexanoate”, which is naturally found in high amounts in fresh spring tea [4]. Unfortunately, this compound has also been observed to evaporate quickly, leading to loss of the signature aroma of Shincha.

But besides that, you may have also noticed that green tea imparts a flowery-sweet odor as well. This is due to other volatile compounds in the tea, such as linalool, methyl epijasmonate and cis-4-heptadienal[5]. Although the amount of these compounds are scarcely found right after the picking of the leaves, they are actually produced during the processing stage and therefore also play a major role in the final flavor. In fact, the researchers have also observed that these flowery-smelling compounds are actually increasing with month-long storage of the tea as well. This means contrarily to the green leaf volatiles, these compounds age well, giving the tea a more mature flavor[4][5].

Hence, if we want to savor the unique taste of Shincha, it makes sense to consume it relatively quickly. But for those wanting to keep the remarkable Shincha notes for a longer time, there are several methods to do so: While a full retention is not possible, the researchers have shown that it is possible to preserve the notes of Shincha for a couple months by storing the tea in a very low temperature (around 5°C) in an airtight packaging, even better when it is stored with nitrogen[6]. Although the researchers had the best results in retaining the aroma of fresh tea by storing the tea in -70°C, our common household technology cannot compete with that, but judging from my former work experiences, freezing the tea (using our common freezer) is not a bad idea as well, if the tea is to be consumed at a later time of the year.

Personally, I think tea is very fascinating in this aspect, as we can enjoy green tea in so many ways. Be it freshly plucked off the field or matured for a longer time; be it refreshingly light and sweet, reminding us of spring or refined with mellow and full-bodied taste. These options, along with different brewing temperatures and occasions, such as cold-brew in summer, make tea one of the most versatile drinks in the world. For now, I am definitely looking forward towards the new tea season coming soon!

*Written by Zyhong Liu, who is also a Tea Fellow at the Global Japanese Tea Association. You can follow Zyhong and learn more about tea science through his website zyhongcha.com

*Photo credit: all photos by Simona Zavadckyte.

References:
[1] Chaturvedula, Venkata. (2013). Tea-Aroma, Taste, Color and Bioactive Constituents. Journal of medicinal plant research. 5. 2110.
[2] Hatanaka, A., Kajiwara, T., & Matsui, K. (1995). The Biogeneration of Green Odour by Green Leaves and It’s Physiological Functions -Past, Present and Future. Zeitschrift für Naturforschung C, 50, 467 – 472. http://zfn.mpdl.mpg.de/data/Reihe_C/50/ZNC-1995-50c-0467.pdf.
[3] Maarse, H. (1991). Volatile Compounds in Foods and Beverages. Marcel Dekker Inc. 624.
[4] Hara, T., & Kubota, E. (1979). Aroma property and its preservation of early spring green tea (shin-cha). Nippon Shokuhin Kogyo Gakkaishi, 26(9), 391-395.
[5] Zheng, X. Q., Li, Q. S., Xiang, L. P., & Liang, Y. R. (2016). Recent advances in volatiles of teas. Molecules, 21(3), 338.

 

Leave a Reply

Your email address will not be published. Required fields are marked *

CAPTCHA