Newbie question about adding water after the boil.

[Fireguy94]

Hey Guys,

Im very new to home brewing having just finished my first all grain beer. I tried it a couple days ago and I'm very happy with it for my first brew. While brewing this beer a question came up that I thought I'd ask the forum.

I started my boil with about 6 gal of wort hoping this would be enough to give me plenty for a 5 gal batch with a rough guess at loosing about a gal during the 60 min boil. unfortunately I was probably around 4.5gal when I was done. Once I transfered the wort to the primary I topped it off with regular tap water to give me the full 5 gals. My question is how does adding water like that effect the beer. I'm guessing it has less body that if I didn't add water. I didn't take an OG before adding the water so I can't compare but I'm betting it would be lower. Does this mean theres less sugars to ferment leading to a less achoholic beer? My knowledge of how the OG and finished OG and fermenting is very rudimentary and I'm wondering if any of you could add some insight.

Matt

 

[BFB]

Next time I'd just rock and roll with 4.5 gallons. A half gallon of water won't make a huge difference but you will lose some overall abv.

 

[Cimerian]

Yeah adding water lowers the OG. Not really less sugars overall but less sugars by volume to ferment so less body and less alcoholic by volume. Way it was explained to me is it just ends up being a slightly lighter beer.

 

[Revvy]

The magic thing is, when you boil off too much and your gravity raises, when you dillute it back to the final volume you intended, the gravity then drops to EXACTLY the gravity you were supposed to have anyway. Look at the dillution calculator in beersmith, or any brewing software and you'll see.

I tend to overshoot my boil all the time by between a half gallon to a gallon, and have found repeatedly that topping off exactly what I'm missing brings the gravity back in line to what it's supposed to be.

In fact, as I show here, that is how I do 5 gallon ag batches on my stovetop doing a 3.5 gallon boil down to a 2.5gallon boil and topping off in the fermenter, just like in an extract batch, to 5 gallons.

When you over boil you concentrate the sugars and the gravity goes higher because of the water evaporating...when you then dillute that amount the gravity decreases.

 

[copyright1997]

Golden Rule: Always take a SG reading (and make sure you adjust it for temperature). That way you can tell if your should/should not add water. Or, at least know what your actual OG level is vs. what the recipe estimated.

Golden Rule 2: If you add water, it's only as sanitary as what is coming out of your tap. So, if your water has whatever, you defeat the sterilization purpose of the boil. In my case, since I am anal about this stuff I have some pre-boiled water in a sanitized container set aside to use in this kind of situation.

 

[Fireguy94]

I was told at the local homebrew store that any water you add before the fermentation is fine cause any bacteria will get killed in the primay. Is this true.