Why Fingerprinting Tea Is a Good Idea

There’s long been some suspicion about whether all “Darjeeling Tea” is really from Darjeeling. After all, Nepal tea gardens are a short hop from Darjeeling and if they are blended or substituted, how many of us would know—especially when we assume our tea is what the label claims?

For tea gardens that produce high-quality tea, this is a problem.

Darjeeling banks on its name, for instance, having been awarded the first geographical indication of India, meaning that its quality is attributable to its geographic origin. Likewise, Assam’s unique environment contributes to its tea’s maltiness, pu’erh’s prestige hinges on its Yunnan province (China) origin, and so on.

Assam teas

When tea is misrepresented or inferior tea mixed in, reputation suffers. In Indonesia, the Chamber of Commerce and Industry is asking for a higher import tax on tea because it’s common for imported poor-quality tea to be mixed into Indonesian-grown high-quality tea. This of course reduces the overall quality and drives down the price!

To combat the possibility of tea being sold as something it’s not, scientists have been developing tools to trace and authenticate specific teas.

This isn’t easy, especially because we still don’t know the entire genomic sequence of Camellia sinensis, and there are thousands of varieties—each with their own properties that affect tea quality—being grown around the world. Complicated further by the processing that tea undergoes, along with a lack of data standardization, this isn’t a straightforward path.

Several tactics are being developed, and newly emerging data are encouraging.

• A 2014 pilot study (W-P. Fang et al.) was promising, having:

demonstrated a DNA fingerprinting method that uses a small set of SNP [single nucleotide polymorphism] markers to verify the genetic identity of a single bud or leaf. This method can handle a large amount of samples in a short period of time and the result is highly robust and repeatable.

• Newly published research focused on identifying the geographic origins of green teas, using markers that included catechins and phospholipids (Navratilova 2019). Preliminary results distinguished between tea that originated from China, Japan, and South Korea.

• Another recent study used trace elements rather than bioactive compounds, thus circumventing the effects that production processes have on tea. According to the authors:

Since the minerals and nutrients present in plants may be representative of the composition of the surrounding soil, plants grown in the same area tend to have their own characteristic elemental fingerprint. (Nelson and Hopfer 2018)

Initial findings were encouraging, with further research ongoing.

• Tea growers in Scotland are particularly anxious to be able to prove that their tea is actually grown in-country, as a single-origin tea, because the UK brand of “Scottish Breakfast Tea” does not contain tea that is grown in Scotland.

On a side note, this type of labeling complicates the entire issue. As another example, although Russian Breakfast and Irish Breakfast tea blends are identified with those countries, the tea itself is not grown in Russia or Ireland.

Anyway, the University of Aberdeen and the Scottish Tea Factory teamed up, comparing trace elements of tea grown in Scotland with imported tea of known origin. As reported in the World Tea News (Burslem and Wainwright 2019):

The results show a promising differentiation of the chemical signature of teas of authentic Scottish origin, possibly reflecting the distinctive background composition of soils in Scotland compared to the traditional tea-growing regions of Africa and Asia.

We can expect such research to continue as reputable gardens and companies seek to protect their name and to assure profits for tea that’s worthy of its price. Sure, many of us may never be able to discern that one tea has been substituted for another, but that’s really beside the point. It’s integrity. And sometimes you have to fight for that, prove that consumer trust is well placed.

Additionally, such studies also take the pulse of the gardens, helping guide plant management and breeding. As the earth’s climate continues to change, these tools may prove worthy of the time, commitment, and research dollars that went into them. The more we know about which varieties thrive in which environments, the better equipped we are to match variety to new growing circumstances—and keep tea a part of the daily routine for future generations.

Oolong from Nepal: Finest Nepal Hand Rolled Jun Chiyabari

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Sources:
–”Authentication of specialty tea: an application note,” by J. Nelson and H. Hopfer, Food Quality and Safety, 12/6/18, https://www.foodqualityandsafety.com/article/specialty-tea-authentication/2/?singlepage=1.
–”Green tea: authentication of geographic origin based on UHPLC-HRMS fingerprints,” by K. Navratilova et al., Journal of Food Composition and Analysis 78 (May 2019):121–28, https://www.sciencedirect.com/science/article/pii/S0889157518311505?via%3Dihub.
–”Kadin calls for review of tea import tax tariff,” Antara News, 3/14/19, https://en.antaranews.com/news/122673/kadin-calls-for-review-of-tea-import-tax-tariff.
–”University of Aberdeen study covers tea authentication,” by D. Burslem and B. Wainwright, World Tea News, 3/11/19, https://worldteanews.com/editors-choice/university-of-aberdeen-study-covers-tea-authentication.
–”Varietal identification of tea (Camellia sinensis) using nanofluidic array of single nucleotide polymorphism (SNP) markers,” by W-P. Fang et al., Horticulture Research 1 (2014):14035, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4596320.

Teas shown here are available at TeaHaus.