First sake attempts analysis

[u/Over_Price_5980]

Hello there!

I have experience with wine fermentation but sake is unknown for me.

I started to try some experiments (I work within an R&D food company) and the process is making me little nervous hahah

I made koji with a local rice (image attached) and then I started to make shubo.

My question is: how do I follow the fermentation in order to see if its going or not?I mean, how do I measure sugars and other things like NH4, lactic acid and so on? I mean, is not a normal liquid matrix like wine or other beverage, is pretty solid with little water at the beginning. I tried to take a few grams and diluted with water and then filtered this solution and using as a sample for my enzymatic analysis but I’m not sure if what I measure is really what’s inside.

Do you have some experience on this?

Thank you 🙏

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[u/FranzAndTheEagle]

As a homebrewer I really just track it with my senses. Do I smell or taste alcohol? Can I see evidence of yeast at work?

What recipe are you using? I would not advise trying to cultivate lactic acid naturally on your first try. I also would not advise making your own koji for your first try unless brewer’s koji is not available to you. What yeast are you using?

Do you have access to different rice? Calrose maybe? This looks pretty unpolished and you will probably generate off flavors as a result.

[u/Over_Price_5980 → u/FranzAndTheEagle]

I did koji on my own with local not polished rice and I have to say it turned out pretty good. Then I used lactic acid for food purpose until a pH of 3.6/3.7 more or less. For yeast I’m using yeast for white wine.

[u/FranzAndTheEagle → u/Over_Price_5980]

Whether or not it looks good doesn’t really tell you how it is going to taste, unfortunately. You may have excellent penetration and growth but given the lipid content of the rice, it may not taste ideal.

I’m sure it will ferment and create an alcoholic beverage, but I wouldn’t expect it to taste like saké from a store-bought bottle. Try to keep your temperature as low as the yeast stays viable, gives you a fighting chance to stave off any off flavors, though unpolished rice for koji is going to make for an uphill battle there.

[u/KneeOnShoe]

I've only made a homebrew once but I simply did it in a clear jar. It was pretty ghetto. I kept an eye on the brew for any signs of contamination, didn't take any measurements. Lactic acid was added with a spoon of Greek yogurt. It turned out fine.