Like the subject says; How long does it take for brew to be ready?

Because I have one at 9% and one at 4% atm and I have Bulbori Gems too I want to brew before it's too late..;

I'm not too sure, but it seems like every hour or 2, it adds 1%. So it won't be done before the brewing closes on the 27th.

Every time you help out the brew (add a brew additive) it will add a percent. You don't have to do this, but it will make the process much quicker. Also, if you obtain an expedient brew agent, it will automatically finish the brew. I do so believe that every hour and a half you will get another percent.