What is Kokumi?

What is Kokumi?

The taste known as "umami" was coined in 1908, but it took about 90 years for it to be recognized as a widely-known flavor. It generally refers to a sort of meaty, brothy sensation. Often it is referred to as "savoriness," but it is more specific than that. Umami indicates the presence of proteins, or even just amino acids, and fills the mouth in the way a juicy steak or shiitake mushrooms would. 

Well, there's a new fancy Japanese flavor in town. It's called "Kokumi." It'll probably be a few generations before it's well-known, so you're getting in on the ground floor here. Kokumi is a bit vaguely defined. It seems to indicate more of a textural sensation than a specific flavor. It is said to refer to a sort of "roundness" in the mouth; a sumptuous sensation that increases the richness of the other flavors present, similar to butter and salt. 

As vague as this sounds, it seems to be legit. Scientists studying kokumi say it is triggered by the presence of glutamyl peptides in foods - molecules that are often found in foods with a lot of umami flavors present, but not exclusively so. These molecules activate the tongue's calcium receptors, which evidently makes the tongue more appreciative of everything else it's experiencing at the same time. 

How does this relate to tea? 

In the world of matcha, everyone is pursuing umami-laden tea. The flavor of umami in tea is often tied to the unique amino acid known as L-Theanine. Well, L-Theanine is in fact a glutamyl-peptide...analogue, meaning the body treats it the same way even though, chemically, we can't call it a proper peptide. In any case, it creates the kokumi sensation! Beyond L-Theanine, there are several other molecules in tea that are glutamyl peptides and lend kokumi sensations to the tea. 

Finally, there is something in chemistry known as the Maillard Reaction. This refers to the ways amino acids and sugars combine when exposed to heat to produce more complex flavors and browning. This is largely associated with heavily heat-treated foods, like grilled meats and vegetables, or dark-roasted teas, but it happens to some degree wherever there is heat. Anyways, the Maillard Reaction, too, produces kokumi-inducing molecules. 

Here's where things get really interesting...

So, it would seem that, since matcha is unroasted tea, if you want kokumi-laden matcha, you have to have umami-laden matcha. This would seem to point in the direction of pursuing the highest L-Theanine concentrations possible. This is something I've written about many times before - the exclusive pursuit of umami in Japanese tea farming has led to the intensive use of synthetic fertilizers and pesticides, and is something I oppose. After all, when umami is pursued exclusively, other flavors get lost - and isn't the point of kokumi that it enhances our appreciation of all flavors? 

There seems to be a solution! A few months ago our contact in Japan was talking to a master tea blender. The tea blender relayed that he likes to "toast" his tencha just a little bit before milling in order to enhance the flavors. He's not darkening the leaves at all, just waking them up with a touch of heat This sounded interesting, so I ordered an affordable electric tea roaster online and started playing with it. We even did some blind taste tests in our tea house with customers who were already well-acquainted with our matcha. 

Across the board, the matcha that had been ever so slightly toasted was appreciated more than the untoasted stuff. It just had an extra sort of...roundness. It seemed sort of like magic. After all, what could really be happening to the leaves when treated with such low heat for a short amount of time that produced such a noticeable difference? Now it is starting to make sense: the Maillard Reaction was at work, enhancing the presence of kokumi-producing molecules! 

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I'll end by saying, you will get to try this lightly toasted variant of our matcha before long. In the endless pursuit of offering the best matcha imaginable, it is simply inconceivable for me to know that we could be treating our tea in a way that improves its quality and then not go ahead and do that. We're figuring out the best way to implement this mild toasting process at-scale, which may take some time, but it's coming, and I will surely keep you posted! 

Thanks for reading and happy sipping,

Simon