Chapter 123 (1/2)
The production process of distiller's yeast is much more complicated than wine making.
Shi Xiong plans to make Daqu of whole wheat, because the amount of wheat in the tribe is OK, and after Daqu is made, it can be made into ordinary low alcohol liquor or high alcohol liquor by distillation.
When Shi Xiong made Daqu at home with his elders, he made Daqu of whole wheat. The Daqu is like large bricks, so this kind of Daqu is also called ”kuaqu”.
When making wine, you only need to break pieces of koji, then grind them into powder, and then sprinkle them into the raw materials according to the ratio of 1:0.007, and stir them evenly. The rest of the work is to let the raw materials ferment by themselves.
Although there is still a lot of wheat left in the tribe, the stone bear is not willing to use it all to make koji.
He just chose twelve bags of wheat with a weight of about 300 Jin and good quality.
Before making koji, stone bear and Kuaima thoroughly cleaned the stone house used to make refractory bricks, then prepared several charcoal pots inside, and hung the thermometer on the wall. This temporarily useless stone house has become a mixing, stepping and stacking room.
Then stone bear began to make koji.
The selected 300 Jin wheat was put into a large wooden barrel. First, 30 jin water was added to mix it well. Then, the charcoal basin was ignited and the temperature was raised to about 20 ℃ in the stone house, and it was allowed to stand for three hours. This process is called moistening.
The wheat soaked with water begins to be ground. The soaked wheat is ground into coarse wheat flour with a stone mill. Then it is sent to the stone house and mixed with water according to a certain proportion.
The water mixing is a very critical step, the amount of water must be appropriate, too much or too little is not enough.
If the amount of water is too much, it is not easy to form the blank when stepping on the koji, and it is easy to deform when entering the koji room to cultivate the koji. Moreover, the billet is easy to be pressed too tightly, which is not conducive to the growth of beneficial microorganisms to the interior of the billet, resulting in the growth of Mucor, Aspergillus niger and other harmful bacteria on the surface of the billet.
In addition, if more water is added, the temperature of the starter will rise too fast and it is difficult to lower the temperature. The time of the starter in the high temperature stage will be prolonged, which is easy to cause a large number of rancid bacteria to propagate, increase the loss of raw materials, and eventually reduce the quality of the finished product.
Similarly, if the amount of water is too small, it will not be easy to bond, resulting in too much scattered, thus increasing the number of broken pieces. At the same time, the water loss of koji blank is too fast during koji cultivation, which leads to the insufficient reproduction of beneficial microorganisms, and also affects the quality of finished koji.
In a word, the moisture content of the starter will directly affect the quality of the finished product, so the water mixing is very critical.
When Shi Xiong's family made koji, they had already figured out a proportion of water. For example, when making this kind of whole wheat Daqu, the proportion of adding water to stir is generally about 38% of the weight of coarse wheat flour, and the maximum is not more than 40%.
And because it is winter koji making, so this time the water is heated in advance. When mixing, the water temperature is about 33 ℃.
With a simple thermometer, you can control the water temperature very well.
It is said that about 6% koji should be added when mixing, but there is no white koji for one year, so it cannot be added.
But it doesn't matter. When the starter is fermented, one more day or so can also achieve the goal.
The mixing and moistening materials are different, in addition to the proportion of water, but also fully stir evenly.
Because if the stirring is not uniform, it will directly affect the uniformity of moisture, nutrients and air permeability, resulting in insufficient starter fermentation.
Stone bear is very experienced in this. When he was making wine koji with his family's elders, he was the one who did the hard work of mixing materials. Who made him a big guy.