What makes tea sweet?

For general/other topics related to tea.

Jul 18th 15 7:36 pm
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What makes tea sweet?

by Thallassa » Jul 18th 15 7:36 pm

I think most people around here are familiar with the natural sweetness in tea, without any added sugar. Does anyone know what chemical compounds are responsible for that sweetness? I assume it's mostly not sucrose/other carbohydrates as tea leaves are pretty low in those.

It's a hard question to google because of course all the results are about *added* sugar (or other sweeteners like honey or stevia), which isn't what I'm interested in. I know what those are!

Yesterday I drank a lapsang souchong which, on the second steep - was entirely sweet and smoke. No significant red tea flavor at all. It was sweeter than teas I've added sugar to! But the sweetness is different as well. Clearer and crisper than sugar, without any of the unpleasantness or bitterness of artificial sweetener.

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Jul 19th 15 9:27 pm
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Re: What makes tea sweet?

by debunix » Jul 19th 15 9:27 pm

I've been hoping someone with more knowledge would answer this one, because I still do not understand sweetness in tea. I remember a key phrase that I've mentioned here before, contrasting Japanese and Chinese green teas:
This firing releases a number of roasted aroma compounds that give the teas a slightly sweet edge. The sweetness is extremely faint compared with the honeyed quality of many Chinese green teas. Japanese green teas have something of a caramelized, meaty bite behind their vegetal flavors, tasting a little bit like the crisp skin off of a roasted chicken.
Harney, Michael (2008-10-02). The Harney & Sons Guide to Tea (Kindle Locations 602-605). Penguin Group. Kindle Edition.

I had trouble with that 'honeyed quality' and comparing this to my early experiences with chinese greens, when I brewed them too long with too hot water and was not using the best quality teas--they were bitter and much less *sweet* to my palate than the Japanese greens. Now I can get sweet from both, but still wouldn't call one or other other sweeter.

And then there is the delayed plummy sweetness of a lovely puerh, the delicate fruity sweetness right off the bat in a fine gold-tip black tea, and the 'sweetwater' phase late in brewing of many teas, and I wonder if they're different compounds that we perceive as sweet vs the sweetness of the delicate young greens.

As I said, looking forward to other contributions.

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Aug 3rd 15 2:05 pm
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Re: What makes tea sweet?

by the_winding_path » Aug 3rd 15 2:05 pm

I know Gyokuro's sweetness (and Matcha & Sencha as well) is mainly due to the L-theanine levels in the tea. This compound adds more than just sweetness, but any Camellia Sinensis var. Sinensis that has been shaded has more L-theanine increasing with the length of shading time as photosynthesis converts it into Catechin. Gyokuro is shaded the longest from my understanding at 20+ days so it has very high levels of L-theanine. Depending on the processing and the brewing parameters it can be more or less pronounced in the cup. It is readily soluble in low temp water which is the main reason Gyokuro has abnormally low temps recommended for brewing. As the temp is raised less desirable astringent and bitter compounds dissolute and lower cup quality.