Why does Earl Grey tea contain bergamot?

Have been lost in the weeds (or better said, tea leaves) putting together a course for World Tea Academy on blending teas with other flavor bearing elements. While I have been having a lot of fun discovering new ways of thinking about tea blending, a deadline looms...

But I can't resist telling you about Earl Grey tea. It's perhaps the most famous flavored tea in the West and traditionally combines a black tea with bergamot, either as peel or oil derived from the peel.

Image from Wikipedia, photo from the “Nürnbergischen Hesperidum - Volkamer”

by Johann Christoph - Nürnberg, 1714.

My exploration of Earl Grey tea led me to wonder: where did Lady Grey get the bergamot to add to the tea? Did she get it from Italy directly or from an orangery at her home, Howick Hall in Northumberland? (Orangeries were popular in 18th and 19th century noble houses—richly windowed buildings where the most exotic tropical and Mediterranean fruits could be grown successfully in frigid Northern climes.) This question led me to learn more about Howick Hall, built and rebuilt over the years starting in the 14th century.

Howick Hall, image from Wikipedia

While I still don't know whether Howick Hall had an orangery or not, I did learn that, of the many legends concerning the origins of Earl Grey tea's formulation, the one cited by the Howick Hall website is as follows: the addition of bergamot was suggested to the Earl by a Chinese envoy to counteract the lime (= calcium carbonate) content of the Hall's water. Water with a high lime content is more alkaline (higher pH) and of course has more calcium than pure water. 

It turns out that water high in calcium limits extraction of tea leaf compounds during brewing, leading to a tea with less caffeine and less amounts of polyphenols. This effect can be modulated by the acidity of the water, with greater acidity (lower pH) leading to greater extraction and less effect of the calcium. Bergamot's acidity would thus counteract this effect of calcium carbonate.

The other effects of calcium carbonate are on the extracted brew itself. As the tea cools down, "tea cream" develops—a turbidity that dulls the shine of the tea. Another problem is that the polyphenols continue to transform, yielding a more brown-orange and less red color. Look for this color change if you add milk to tea in a glass. Both of these transformations would make the tea less attractive to people who are used to a redder tea, with or without milk.

Black tea with and without milk—notice the color difference! Photo by Joanna Kosinska on Unsplash

But mostly, a lower pH yields a tea that simply tastes better.


Oh, and why bergamot instead of, say, lemon, which could accomplish the same goal?

I would imagine that it is because bergamot is more fragrant—and more exotic—than lemon. 

If you like your black tea better with lemon than without, now you know why.

==> Three Basic Teas & How to Enjoy Them, available in paperback and Kindle on Amazon!

References:

Yong-Quan Xu, Chun Zou, Ying Gao, Jian-Xin Chen, Fang Wang, Gen-Sheng Chen, Jun-Feng Yin. Effect of the type of brewing water on the chemical composition, sensory quality and antioxidant capacity of Chinese teas. Food Chemistry, Volume 236, 2017, Pages 142-151, ISSN 0308-8146, https://doi.org/10.1016/j.foodchem.2016.11.110.

Chandini, S. K., Jaganmohan Rao, L. and Subramanian, R. (2011), Influence of extraction conditions on polyphenols content and cream constituents in black tea extracts. International Journal of Food Science & Technology, 46: 879-886. doi:10.1111/j.1365-2621.2011.02576.x