1st batch was fantastic, tasty, sweet, delicious hot and cold.

I used the same process for 2nd batch: Cooked the rice 2 cup water/1 cup rice ratio, let it cool in a container 3/4 of rice and a fine layer of koji (saké yeast), then added rice, yeast, etc up to the top, put a loose lid on top, stored in the coolest part of my house, after 1-2 weeks the rice ferments, the saké begins to form... I tried it, and ewwrrrhh... sour!

Last time, the taste was perfect, ready to bottle.

Here's my question: should I add a bit more sugar to make it sweet? Or will that ruin it more?

Thanks a lot!

  • Don't know much about sake, but with sour, do you mean acidic, like vinegar e.g.?
    – chthon
    Mar 22, 2020 at 19:35
  • Yes, kinda strong vinegar taste.. usually saké has a little vinegar-ish taste.. but last time, unbearable Mar 23, 2020 at 21:57

2 Answers 2


Based upon your answer in the comments, I suppose that your sake has been contaminated by acetobacter. These bacteria convert ethanol into vinegar. That means you now have nice sake vinegar. As such it is probably usable in your kitchen after pasteurizing and somewhat diluting it.

Now as for the source of the contamination, you need to take into account proper cleaning and sanitizing practices throughout your process. Buy a cleaner like PBW, a no rinse sanitizer like Star San, and make sure that all your equipment is clean before you start, and that your fermentation vessel is sanitized before you add the ingredients to be fermented.

When you let things cool, cover them with a lid and possibly with an extra towel (over the lid), also to avoid contamination.

Hopefully your next brew succeeds again.


Ive had some of the same experiences with Sake. my first batch was so delicious, the next one..not as much. It seems to me that a possible contributor to your situation is that the solution was allowed to sit undisturbed for too long. I have had batches of Sake turn when they were allowed to do their own thing for too long. As a brewer, I was more than a little surprised by the process differences from beer to Sake in that Sake needs a lot more gradual attention, in the form of stirring and additions of rice Ect.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.