Some beginner's questions

My first batch of sake is in it’s primary fermentation.
On day 5 of the primary it looked like photo #1
(35L. sake - 30L. krauzen)

This morning (day 13) I opened the vessel and took a hydrometer-reading.
I read somewhere around 1005. Photo #2 shows a bird’s eye view of the moromi.

It tasted like sake , not sour at all, and sort of nice but the taste/smell of Koji was very much present.

question: will this koji smell subside?
next question: I am planning to start pressing in about 7 days.
Will the krauzen dissapear?
Should I remove the upper part of the moromi/yeast before starting pressing?

Any advice on this would be appreciated a lot.

If you made your own koji, then the aroma of the koji will be present in your sake until you pasteurize it. Pasteurization completely dissipates the cheeselike aroma of koji.

[quote=“janjanssen”]next question: I am planning to start pressing in about 7 days.
Will the krauzen dissapear? [/quote]
That kraeusen is a good sign, it indicates that you have a good strong fermentation going. By the time day 19 or 20 rolls around, the foam will have collapsed back into the moromi. There is no need to worry about removing it.

Hello Taylor

Thanks for the reply. You’re being very helpful and so was your recipe. I guess I’d have never made it this far without it. I did in fact make the Koji myself (for no other reason than that it was the only available option). I’m glad to hear the koji-aroma will go away after pasteurization. You’re advice on the disappearing Krauzen was also comforting
Now I have another few questions, this time about (sugar)additions. I would be glad to hear your opinions on those and learn from them. I’ll open a new thread as to not mingle too much different subjects in this one thread.

If janjanssen doesn’t mind me attaching myself to his thread, I have a question to ask, and this seemed the appropiate place. I to am a little more than a week into the primary fermentation of my first batch of sake. Something I have noticed is a thick layer that has formed on top of the moromi. It appears very much like the “topview” photo from the first post, except with out the foam. Is this normal? The batch is still actively fermenting underneath the layer. I have stirred it a couple of times to see if it will mix back in, but it reforms. Other that this “layer” the batch seems to be doing fine. It has the right sake taste and much alcohol. Thanks,


That’s just a matt of rice, yeast, and koji that has been carried to the top of your moromi by its natural buoyancy and its tendency to catch CO2. The rice loses density as its starch is hydrolysed by the koji enzymes, and as it loses density it tends to float. It’s perfectly normal and nothing to worry about. See:

Yep, that’s pretty much exactly what it looks like, even with the thermometer probe. I was hoping it would be someting of that nature, but I just wanted to be sure. Thanks.

As a side note, with the method of temperature control I am using, the layer has made it necessary to take the top off the bucket to get an accurate temperature reading. Heretofore, I had just been putting the probe through the airlock hole. The observations I have made indicate that the temperature reading, that way, will be an average of 2-3 degrees higher than the actual temperature. Just an FYI.

Thanks again.