The Art of Milling Matcha
I've spent many, if not most, of my blog posts talking about the artistry that goes into growing the tea we use to mill our matcha. It honestly may be a Minnesotan thing to downplay our own role in the production of great matcha, but let's challenge that. A little pride can be a good thing, right?
I was speaking to a friend in Canada recently who had brought some of our matcha with him to share with his friends there. He said that they were big fans. Apparently they have a few mills of their own up in Vancouver, yet his tea group was asking what sort of process we use because our matcha was so much finer than the local ones. Maybe he was just being a good friend, but let's talk about making finely-ground matcha anyways!
The Fundamentals
We use the old-school, hand-crafted Japanese matcha mill stones. These are made from hand-carved granite by a few certified masters, and are all standardized to a 33 centimeter diameter. If you look at the picture above, you can get a sense of the pattern that is carved into the stones; many narrow grooves channel the tea leaves towards the edge of the stone before hitting a final centimeter or so of no grooves at all. This final centimeter is where the powder goes from fine to super, microscopically fine. It is worth noting that it takes two such stones to mill matcha. One is stationary, while the other, on top of the stationary one, is pulled in circles by a motor.
This may seem conceptually simple, but it turns out that matcha mills are quite a finicky thing, and we've had to learn through a lot of mistakes to get where we are today (perhaps those mistakes would make a good follow-up post). For now I'll mention that most mills are not like this. Mills for flour, for instance, do not have nearly so many grooves cut into them. Flour mills also tend to be a lot bigger and move a lot faster than matcha mills, which is why they are able to crank out several kilograms of flour per hour, while we can do more like 40 to 50 grams per hour.
Now, it is possible to use other mill types on tea leaves. Larger-scale factories have certainly tried to do this. However, it would seem that even factories with all the bells and whistles have trouble producing a powdered tea with the fineness and delicacy of ceremonial grade matcha. This is why, if you look at factories producing high quality matcha in Japan, you'll see rows and rows of mills that look more or less like ours, each one moving oh so slowly.
Why Go So Slow?
There's a matcha shortage, after all. Can't we just hurry up? Unfortunately, not if we want good matcha. There are a few distinct advantages to going slow when it comes to matcha milling.
The first is particle size. We want the finest matcha possible. A matcha so fine it rises like smoke when you sift it or open the container. This is primarily because finer matcha equals creamier, smoother matcha. If you've ever had the experience of whisking up a gritty bowl of matcha, you know just how unpleasant that experience is. Matcha doesn't dissolve in water - it just appears to. At the end of the day, when you are consuming matcha, you are consuming a mass of solid particles masquerading as a liquid. Essentially, our job as matcha millers is to to get the particles so fine that you cannot tell that you are drinking anything but a liquid when you whisk it up. Milling slowly is critical here, because the more time the tea leaf spends between the two stones, the more it breaks down into a finer and finer powder. The slower you mill, the finer the powder.
But if the goal is to simply increase the amount of time the tea particles spend between two stones, why not just use larger stones and mill at a higher speed? This is where heat becomes a factor. If we let our matcha mill run all day, the stones get quite warm and start radiating heat. But they only ever get warm, and never hot. If you use larger stones at higher speeds, suddenly the friction generated by the mill will make the stones downright hot. Meanwhile, the matcha particles between those stones are microscopic and extremely delicate - too much heat will release their volatile aromas before they leave the mill, let alone make it into your bowl.
By optimizing particle size while minimizing aromatic degradation due to heat, the standard Japanese 33 centimeter mill stones really are hard to beat. It does mean, however, that we won't be able to make them work faster any time soon.
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Alright, that was a lot, so I'll stop it here for this week. Beyond having the right stones, there are additional steps we've had to implement to make sure our matcha is the right texture and our mills don't get grumpy with us - but I'll write about those on a later date.
I'll leave you with a final tip. If you want to test the fineness of your matcha, grab a piece of paper, dip your finger in the matcha, and smear it across the sheet. A really well-ground matcha will behave almost like paint, even in the absence of a liquid.
Thanks for reading and happy sipping,
Simon