Expert: Matt Dick - 3/20/2008

Question
I brewed a batch of beer several days ago.  I now realize that I actually did not top off the wort to make a full 5 gallons; I have closer to 4.5 gallons.  Should I let it go; add water now (it is fermenting perfectly) or add water when I prime for kegging?  What do you think?

Answer
Scott,

Good question.  I think you should let it go.  

You'll end up with a more concentrated beer, but that's not going to hurt anything.  If you interrupt the fermentation now, you risk contamination again, and that's not a good risk when there's beer at stake.

If you do add water, I would make sure it's boiled for more than five minutes (and cooled again), and then add it quickly while the yeast is still active so it has time to replace the air you introduce with CO2.

But ultimately I would wait, you're likely not to taste a huge difference and right now the beer is happy, and when beer is happy, everyone is happy.

What type of beer are you making?  Is it in a carboy or a bucket now?

Good luck!

Matt