Topping off during fermentation

[GrandpasFridge]

New around here though I've been reading for weeks.

I just brewed my 2nd 5 gal batch (BB American Amber) on Saturday and bottled my first batch (BB Oatmeal Stout) on Sunday. Both extract kits w/ specialty grains & 2 1/2 gal boils.

In both cases I tried to be careful when topping off with water not to drop below the expected OG stated in the instructions. In both cases that meant I stopped about 1/2 gal short of 5 gallons.

I just read on a thread here where my mistake was, I didn't thoroughly blend the wort with the water before taking my gravity reading, so I haven't the faintest idea what my actual OG was.

I'm curious what I can expect (a little more alcohol / a little more body?) but am willing to wait to find out. It's gonna be good, I just know it.

But I'm also curious whether topping the Amber Ale in the primary to 5 gal now or even at transfer to the secondary would be a horrible idea - it's still bubbling (maybe a click a minute). I'm guessing the risk of contaminating is greater than the benefit, but thought I'd ask.

 

[Cummins9320]

I wouldn't add any water after it has already started fermenting. I think it would just be asking for contamination.

 

[Dougan]

The contamination risk is there, but depending on your water source, not a show-stopper. I top off at the end of a brew session, before fermentation, often, and haven't had trouble. But, either way, it's not the biggest concern-- it's the fact that there's oxygen dissolved in the water. So you will oxygenate your beer, even if you do it slowly.

I would recommend not doing it. 4.5 gal is close enough to 5 gallons-- your beers will be good either way. All-grain brewers miss their mark by 1/2 gallon frequently, and it's just normal. So nothing to lose sleep over.

As far as your original gravity, when doing extract, there's not really any surprises-- if you enter the recipe into a recipe calculator (see my sig) and set your volume to 4.5 gallons, it will estimate your OG, and for an extract batch, it should be very close to your real reading. It's when you get into all-grain brewing that your OG can fluctuate. So just estimating your OG should do the trick-- it's not the ideal situation, but it will work fine.

 

[how1]

I would not add any more water at this point. You"ll have a little higher ABV%. Adding more water after a majority of the fermentation is done will risk adding oxygen. I am sure your beer will turn out great.

 

[GrandpasFridge]

Wow, what a great forum. I hardly had time to use the facilities and grab another from the fridge and I've got my answer.

I'll take your advice, chaulk it up to experience and just use what I learned next batch.

Thanks for the recipe calculator Dougan ... I'll use that to figure where I'm at. It doesn't really matter, I'm going to enjoy drinking it regardless, but I can't help but be curious.

 

[AdamPag]

it happens to all of us, although SOME of us add a little extra water when priming to make up the Evap difference. I personally opt to add an extra .25 gals in top off water with no noticable difference