Sake Question

Good question; I'm doing the same thing, but today (at day 34), my specific gravity is 1.022 with the refractometer.

I made sake last year and wondered the same thing. You begin with rice - lots of starch - then you add koji, to convert the starch to sugar, and yeast to ferment the sugar *simultaneously*. That means there is no initial fermentable sugar to measure, and just to make things more complicated you typically add rice multiple times.

I considered separating the starch-to-sugar conversion from the fermentation. Add the koji, alone, and pitch the yeast when it was done; home brewers might think of this as a "mash." Then hydrometer readings could give you the final alcohol content of your sake. This approach increases the risk of infection, though, because the nasties will have a crack at all that sugar well before your yeast does. It would be tempting to use sulphite here, but I think it would suppress the koji along with any spoilage organisms.

So I just decided to carry on without knowing the alcohol content, and think of it as part of sake's mystery :)

Erroll

Er, maybe this is stoopid, but the koji ought to be metabolizing pretty much all of the starch to sugar, so take as a baseline the amount of starch and assume that is fairly close to an equal amount of sugar. Then the old "half-plus-one rule" might apply? [Half-plus-one rule: Take the % sugar, divide by 2 and add one to the result to get a ballpark estimate of the final alcohol content. So 15% sugar works out to about 8.5% alcohol.]

Here is you used 1.5 kg rice per 4 kg water = 37.5% sugar (eventually) ==>

This is what I've been using and I'd love to hear if anyone thinks it actually makes sense.

-- j

There are no z's in my address.

Hi Jeff, Well stoopid or not that's how much alcohol I am supposed to end up with so I guess it's a good formula! Louise:o)

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