Japanese sake brewing project (6) ~ Pressing / Pasteurization

Pasteurization -- deactivate fermentation and kill unexpected bacteria and etc.

Pressing

After the last addition (the third addition), the fermentation was active for more than 2 weeks.   A timing the fermentation to be stopped is one of key decision for brewing sake.   Many article on the internet mentioned, it would be around 2~4 weeks from the last addition.

In my first brewing, I decided to stop the fermentation after 17 days.

Pressing method

In my test brewing before this batch, it is very hard to press just using a close.  Therefore, I thought using a metal mesh would be a good idea to separate / extract the liquid part and sediment.  My fermentation tank has  "a down spout".   When I brew beer, using it to take beer out from the tank.  The contents will be separated with 3 layers after a several days of the fermentation.   The middle part is the liquid part and it is probably easy to extract the liquid part from the down spout.

Actually, it was a good idea.   The middle part is really liquid and not much sediment included.  Then we can minimize the pressing effort.   I extracted the middle layer from the spout and total amount of the liquid part is about 1.5 gallon.   Then the left over is pressed with a metal mesh.   However, the sediment is soft and if we press the sediment, then the sediment passed through the mesh.   With this process, I got about extra 1 gallon of liquid with a lot of sediment, it is called "Nigori" in Japanese.

Pasteurization

After pressing process, I did pasteurization that deactivates the fermentation and kill unexpected bacteria and etc. to store in the room temperature.   The process is put a jar that has the liquid part into a larger jar to heat up.   I put a thermometer to monitor the liquid temperature.   Based on the information on the internet, the temperature needs to be up to 60C+ (140F+).   Then chilling the liquid immediately.   After that, it will put in jars to store.    It will take a few weeks to settle the sediment into the bottom.

Tasting

 I tasted it after the process.   The taste was not too bad.  Actually, it is much better than I expected.  I still needs to wait more time for aging the sake.   However, I started considering how I will proceed the next batch.

(To be continue)