The process of making sake starts with washing the rice.
Today they would do this with machines, churning the rice with water and grinding it down until a percentage of the original grain is left. (This is also the difference between the different types of saké like daiginjo and ginjo if I know my stuff)
Back when they didn’t have machines people would wash the rice by filling shallow barrels with rice and washing the rice by stepping on it. (Not so different from making wine actually)
Washing rice, lots of it. Saké was made in large batches so lots of rice needs to be washed. (Economy of scales)
Rice was them steamed to turn proteins into amino acids and carbohydrates into simpler sugars.
This creates food for the koji cells that will grown on the rice and ferment.
How much to stream was up to the boss’s experience and it was tested by making a paste out of the steamed rice and feeling its texture.
The large pot they would have used to steam the rice. After the rice was done someone would have to crawl inside and shovel out the rice to be cooled on mats laid out on the floor.
After cooking the rice it was shoveled out of the large pots and laid out on mats to cool.
Mind you, all this was done by hand.
So someone needed to crawl into the pot with a wooden shovel to cut out blocks of rice like one might cut blocks of snow for making an igloo and people had to spread the hot rice out by hand first.
Laid on the floor to cool until it's just right for mold to grow in it.
Next step is molding the rice.
You might think this is as easy as leaving it out for a day or two to get that green fuzz growing but that’s not the right mold.
They maintain the temperature inside a hut around 30℃ and start by sprinkling the mold spores on the rice.
As the mold grows it releases heat so the rice, now in multiple trays stacked around the room, need to be rotated often.
Growing koji mold for sake in a hut. Must have been hot in there...
After they have moldy rice it’s mixed with water to make moldy rice water.
This moldy water ferments to become the fermenting agent when they make the sake.
The images I saw of this had people singing and rhythmically pushing rice around a barrel with long sticks that looked like they coins be used in a big game of roulette.
They call it 酒母（しゅぼ）or mother of saké. It's what will be dumped into a large barrel with some more water to create saké.
The shubo and more water goes into a very large barrel where the mixture ferments some more.
After this step there’s no more fermentation, just filtration and pasteurization.
People had to stand watch over the barrels of fermenting saké to cut down bubbles and stir the mixture from time to find using other barrels filled with warm water to maintain the desired temperature.
The saké and lees mixture is called moromi. If the temperature got colder they would sometimes need to wrap mats around the barrels to keep them warm.
From here on in we have drinkable saké. The next step is filtration and any saké taken at this point is called raw (or live) saké since it hasn’t been pasteurized and is technically still fermenting.
The moromi is stuck in bags and then a large pile of those bags are presses to squeeze out the saké.
I suppose that depending on the fineness of the filter used here we get the “unfiltered” cloudy saké and the clear saké.
The rectangle in the back is where the bags of moromi go in. The top is then pressed down using weights and levers to squeeze out the saké.
The last step before packaging and shipping is pasteurization.
The filtered saké is brought up to a temperature just high enough to kill the fermenting molds and we have our saké ready to ship.
More big barrels, they like their barrels...
And thus goes a general overview of how saké is made.
It was cool how they had a display of all the tools that were used in the process and explanations of how they were used.
The display of skazuki from around Japan was interesting too.
There were a bunch of different shapes and sizes including ones shaped like cones so you couldn’t put it down once you were poured some…
None of them are capable of standing by themselves. Some even have holes in them that you need to cover with your finger so you can't give your cup to someone else. Is it weird I had more fun here than I think I would have at Universal Studios Japan?