Did you ever look at a field of rice, and wonder how many bottles of sake could be made from it? Maybe not. Regardless, it is not an easy question to answer, because there are way too many variables in the brewing process that affect yield. One is how much the rice was milled before brewing. Obviously, if you grind away the outer 60 percent of the rice, your yield is much less than if you only grind away 25 percent.
Another variable is how far you let the fermentation proceed. Fermenting until every last starch molecule has dissolved will give you much more sake for the rice than stopping fermentation earlier. But squeezing out every last drop of yield takes a huge toll on quality. Also, whether or not alcohol and/or other flavorings are added, as is the case for cheap sake, can have a great effect. (Yields for cheap sake are double what they are for premium sake.)
With all this compounding error, it is very difficult to say how much sake can be brewed from, say, a ton of rice. Still, it’s an interesting question. So let’s see . . .
To do this, we have to set up a few boundary conditions. Let’s say the size of the batch is one metric ton of rice, and that we are brewing junmaishu, so no alcohol has been added. Let’s also say that the seimai-buai is 60 percent, so that the outer 40 percent of the rice has been ground away.
Finally, let’s assume that the moromi (the fermenting mash, one ton of rice) was allowed to ferment to the extent that, when the sake was separated from the leftover rice solids, there were 2000 bottles of sake. (A number supplied by a brewer as typical.)
Now, on to the land. Rice is sold by farmers in 60-kg units called hyo. A basic unit of farming land is 10 meters by 100 meters, and is known as a tan. Ten tan, or a 100 x 100-meter plot, make up one cho.
Since every rice strain is different, and since things vary from place to place due to weather conditions, we are starting to compound errors again. But for much sake rice, 1 tan yields 8 hyo of rice.
Readers with the requisite math skills will see that 1 tan yields 480 kg. But wait! Keep in mind that this is brown rice, and we are using rice milled to 60 percent. So, to get one ton of our polished rice, we need to start with 1.66 tons of brown rice.
Firing up the calculator again, we see that we need about 3.5 tan to yield the 1.66 tons of brown rice. So, in the end, an area of 35 x 100 meters (about the size of a football field) will yield about 2,000 wine-bottle-size bottles of sake.
Please allow me to reiterate that the assumed degree of accuracy is appalling from an engineering standpoint. But still, it’s kind of neat to be able to glance out over a golden field of rice, and think, “Now let’s see . . .”
Rob Yellin and I will host our second sake and pottery seminar of the year April 14, at the sake pub Mushu. For information or reservations, contact me by e-mail or fax.
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Tenju (Akita Prefecture)
A settled flavor, mildly fragrant, with an overall fresh feeling, yet a decent umami in the recesses. Fairly typical of the style of sake from Akita. Tenju also makes a sterling daiginjo called Chokai that is worth the search.