Fermenting in 4 gallons, topping off with a 5th later

Hi everyone,

I am using a 5 gallon glass carboy to brew 5 gallons of beer, so to get around losing a lot of beer and/or blowing the top off the fermenter the guy at my local homebrew store suggested fermenting 4 gallons and once the vigourous part of the fermentation cycle is done to top it off with the 5th gallon.

Here is what my process was...
1 - add 2 gallons of water to the carboy
2 - boil 2 gallons of water and brew wort
3 - cool wort and add to carboy, making 4 gallons

I did this on Friday, and I added the 5th gallon yesterday.

Has anybody else tried this? Will this affect the final product?

Thanks,

mechedd

I'd be concerned about adding oxygen to the mix after the bulk of the fermentation is complete. Anybody else have this thought?

I'd probably do a 15 minute boil on that final gallon to remove the oxygen from it...

if he siphoned it carefully it should be ok...definately boil the water first, before you add it. You could just use the full five gallons and use Fermcaps to prevent blow off next time. I never liked the idea of diluting with more than I boiled, so adding 3 gallons plain water to a 2 gallon boil was not my thing.

I'd let it cool a little bit too. Something about adding boiling water to a fermenting beer just doesn't sit well with me...not that I know what would happen..it just doesnt feel right.

+1 on the siphon

Get a 6 gallon fermenting bucket. The extra space allows for minimal blow off, you might still have some, but all the goodness is in the same place. Your LHBS should have a 6 gallon fermenting bucket. I did what you described once, beer was ok (my first brew), but what a PITA! I didn't boil it, just siphoned from a jug to carboy.

s1080 said:

I'd let it cool a little bit too. Something about adding boiling water to a fermenting beer just doesn't sit well with me...not that I know what would happen..it just doesnt feel right.

+1 on the siphon

Click to expand...

Small oversight in my post above. Boil to remove oxygen, then cool before adding...

s1080 said:

I'd let it cool a little bit too. Something about adding boiling water to a fermenting beer just doesn't sit well with me...not that I know what would happen..it just doesnt feel right.

+1 on the siphon

Click to expand...

lol, i meant this, didn't say it specifically though...