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How to make sake with dried koji rice?

I wanto to make sake and I asked a Japanese friend who lives here in Italy to bring me koji from Japan.
She gave me a packet with rice, and it seems to be dried koji.
How have I to use it?
I have to rehydrate it with water before to put it in the rice or have I to use it dried?
Do you know what have I to do?

What quantity of sake do you plan on brewing and how much koji do you have? In what state are the rice?
To of it sounds like you have got yourselves some kome-koji, which is the mold koji grown on rice. Generally this is added directly to your sake brewing in all additions steps. However the amounts added are measured as hydrated rice. Therefore you could potentially hydrate the rice to contain 40% water based on weight.

If you want to learn more about sake brewing check out the guide and recipe on linked below :slight_smile:

Thanks for your links!
I want to make 5lt, about 1.32 us gallons.
I read on the site you linked and it says to use about 860gr of raw rice, but another recipe on another web site uses about 2000gr to make the same quantity.
It say that rice to koji should be as 100:25…
So how much dried rice, dried koji and water should I use?
I have no ske yeast, but I have white wine yeast and its nutrients.
I have not Magnesium sulphate and Potassium chloride, should I use them
Usually to make wine with this yeast I have to use 1gr evry 1lt, so to produce 5lt wine I use 5gr, have I to use it in the same way?Have I to use 5gr to make 5lt sake?
About the nutrient it is a mixture of mineral salts and I use about 0,5 gr every 5 lt.

By the way I have 300gr of dried koji, so if I have to hydrate it would become about 400gr

Generally rice amounts are given as prepared rice. So the 2kg are likely prepared rice.

Also the recipe on does not currently describe how much sake you actually get from using it, and I understand your frustration. This will be added in near future.

The thing is that with sake you need a large fermenter to brew a small amount of sake. Generally a 5 gallon fermenter is filled up to 4 gallons and only 2 gallons of sake is made based on this. The yield will vary depending on how successfully you press your sake.

I hope this answers your question :slight_smile:

So, by making the proper proportions I reached this recipe to produce 4lt of sake:

300gr of koji (from 213 gr of dried koji),
1200gr of coocked rice,
2lt of water,
1gr yeast nutrient,
4gr white wine yeast.

I’m going to do it with these quantities.

I have another question:

the guide says to use a fermenter, but I have not one, so can I use a 5lt glass bottle?
Have I to close it with a airlock during all passages?
I don’t understand if the mixture has to be closed inside the fermenter to avoid the contact with the air or it can be simply placed in a opened bucket…

I have already answered this question in e-mail. The dried koji in question is exactly the same thing as the Cold Mountain dried rice koji called for in the recipe in my guide. Use it exactly as called for in my recipe: measure it by volume, add it directly to your fermentation vessel. No soaking or other additional preparation is required.

Use a food grade plastic bucket. If you use a carboy, demijohn, or any other such narrow-neck rigid glass fermenter, you will regret it. I promise.


I thought my instructions and photos were pretty clear here: whenever you are not actively adding ingredients or stirring the contents, the fermenter needs to be sealed with a tight-fitting lid and airlock. Despite all the stirring and opening of the fermenter that goes on in this process, this is not an open fermentation.

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