Adding water to secondary

If a batch is supposed to be 5 gal but only ends up being 4.5 gal, is it ok to add in an extra half gallon of water to the secondary fermenter? I would boil the water first and then cool it down to the same temp as the wort in the secondary. I think i forgot to add the extra half gallon when i filled the primary. The FG reading is about 4 points higher than the recipe is calling for and my reasoning is to add the extra half gallon of water to bring the gravity down those last 4 points or so.

It's certainly permissible, but you do carry an increased risk of infection by adding anything to your fermenter. You also increase the risk of oxidation if you're not careful about how you add the top-up water.

If it tastes good, I say RDWHAHB, and don't worry about losing a half gallon of volume. Learn from this brew and apply the lesson to future beers.

Messing with the secondary can cause problems.
No recipes are exact - so don't worry about being dead on. Good beer is good beer, even if it isn't 100% according the the model.
Also, depending on the time/temp/yeast, you may drop a few more points.

If you are dead set on getting an additonal 1/2 G, I would do it at bottling time:
ie) mix the bottling sugar to 1/2g of boiled water. It would also need to be cooled before being put into the carboy. This would not give you more ABV - but would increase the volume of beer...and decrease the flavour/body.

I wouldn't add anything to the secondary (except maybe hops!).

The time to top up is before fermentation and after the wort has cooled when aeration is actually a good thing. We usually check the gravity after the boil (we do a concentrated boil), calculate how much water to add, add just a bit less than we think, find that we've just about hit our target OG and then aerate and pitch. Volume should be the least of your concerns.

That said, if you insist on adding liquid to the secondary, I liked the idea of adding it with the priming sugar, since you're going to boil that water and thereby drive out the dissolved O2. Just remember to cool the water-sugar solution first since that much volume will really drive up the temp!

Moon

I wouldn't bother, i had a similar quandry, i was trying to make any easy drinking summer beer ended up with just over 4 gallons with what was going to be 6%. I was going to add some boiled water the next day before the yeasties entered the anerobic stage but was to slow and missed the opportunity.
I decided against adding water even when boiled (it takes a long time to totally deoxygenate water by boiling) in the fear that i would get oxidation byproducts.

So im left with a golden summer ale thats going to make me fall down a bit quicker than i had planned but thats not such a bad thing.

IMO leave it alone and chalk it up to experience.

Ah, so the oxygen in the water that I would pour in wouldn't be eaten by the yeast since there wouldn't be enough yeast in the secondary thus possibly causing oxidation in the already fermented beer. Whereas if I added water to the primary before fermentation started, the yeast could use the extra oxygen in the water. That in effect would be aerating the wort even more.

robbase9 said:

Ah, so the oxygen in the water that I would pour in wouldn't be eaten by the yeast since there wouldn't be enough yeast in the secondary thus possibly causing oxidation in the already fermented beer. Whereas if I added water to the primary before fermentation started, the yeast could use the extra oxygen in the water. That in effect would be aerating the wort even more.

Click to expand...

Sort of. If you boiled the water first, then added it carefully, there would be little to no oxygen introduced. Otherwise, you'll be introducing oxygen, and the yeast will not consume it. Not because there isn't enough yeast, but rather because there is enough yeast, and it is finished with its reproduction phase, the only aerobic phase of fermentation.

If you were to add water at any point, can you figure out what the SG would be using this formula?
4.5 gals of wort at 1.064
adding .5 gal of water at 1.000

((4.5x1.064) + (.5 x 1.000))/5 = 1.057