[dons]

Okay, I got your attention.  

After a discussion with a friend, we ended up with this issue.

Being frugal, we want to make the most beer possible - within the recipe.  The question is this:
A lot of people (those with 5 gal carboys, anyway) suffer from loss of potential beer with an active blowout
process.  I just lost nearly a full gallon (another story for another time).   IF, to avoid that, say a person did a strong, long boil and ended up with 4 gallons of wort.  Then after 3-4 days when the blowout has subsided, COULD he add a gallon of water to the primary and end up with the beer the recipe intended?

Taken it to an extreme level of silliness one might end up with the soft-drink syrup process - which I know is just, ummm, silly.  But to the extent above, would there be anything lost?

[majorvices]

You should be using 6.5 gallon carboys. You won't lose nearly as much beer. I have 6.5 gallon carboys and almost never have a blow off and rarely loose more than a quart (and I fill them up closer to 5.5 gallons). Also, to control the amount of blow off pitch a proper amount of yeast at the proper termp, aerate properly and maintain proper fermentation temps. Believe it or not making a starter and pitching cooloer and fermenting cool will remarkably decrease the amount of blow off.

[ccarlson]

To answer your question, I think you could do what you proposed, if you take this into account with your hop utilization. Be sure and use boiled and chilled water to top off.

Also, while I personally don't care for the stuff, you could also use a foam control product.

[majorvices]

Yeah, agree you can do it that way but you simply shouldn't have to!

[tschmidlin]

You can also brew 4 gallon batches and avoid having to get new carboys.  On the other hand, you can add (boiled, cooled) water like you suggested or you can add carbonated water to the beer when serving.

[ccarlson]

I like this idea and I have the same problem. Several carboys and they're all 5 gallon ones. I rarely use them anymore, but this gives me some options.

One other thing, keep in mind that a more concentrated wort will generally result in a more active fermentation.

[b-hoppy]

I used to have the same problem but switched to using two carboys for the ferment.  I know it's a little more cleaning but I never worry about foam overs any more.

[denny]

It's obviously a personal subjective decision which way is easier, but I think I'd go with either bigger or more fermenters and deal with the issue at the source.

[ccarlson]

It may be a money issue. We aren't all endowed with an abundance of disposable brew money and have to make the most of what we have. At least that's my case.

[Joe Sr.]

It's not "disposable."  It's an "investment." 

It's easier to justify that way.

[weithman5]

scale back the batch size would be the easiest

[yugamrap]

Try one of these: http://www.northernbrewer.com/brewing/brewing-equipment/fermenting-equipment/buckets/7-9-gal-fermenting-bucket.html

It will hold a 5.5-gallon batch without substantial loss to blow-off.  It's easy to carry.  It won't shatter.  It's easy to clean.  With proper care it'll last at least a couple years.  I get a new one each year as a holiday gift and retire the oldest one in the fleet.

[tom]

That's exactly how the big boys do it to maximize the use of their equipment.

The water you add should be sanitized and de-aerated (i.e. boiled and cooled).

[Slowbrew]

Try one of these: http://www.northernbrewer.com/brewing/brewing-equipment/fermenting-equipment/buckets/7-9-gal-fermenting-bucket.html

It will hold a 5.5-gallon batch without substantial loss to blow-off.  It's easy to carry.  It won't shatter.  It's easy to clean.  With proper care it'll last at least a couple years.  I get a new one each year as a holiday gift and retire the oldest one in the fleet.

+1

This was my first thought.  Far easier to buy a bucket and get enough head space to handle the problem.  You can still use the 5 gal. carboys for secondary fermentation if needed.

Paul

[ccarlson]

How hard is it to boil a little longer? I think it's a good idea.