I'm in the process of making sake:

I started by making my Kome-Koji with 400 gr. steamed rice and Koji-Kin,
then I mixed that with 1.5 kg steamed rice and 4 liters water 1/2 tsp.
citric acid and yeast

and I've come up with a question...

How do you measure the SG?

I checked with my refractometer and it read "0"
It's 3 days into fermenting and it now reads "10"

How do I know in the end how much alcohol will be in this stuff?

Louise)