Gravity scaling for volume

[Chombo]

Hi,
i just finished a brew session and my gravity for 3 gallons of wort (before i added 2 more gallons of water at the end) was 1.068.


is there any calculator or formula that exists where i can figure out what my gravity would be with the 3 gallons of wort and 2 gallons of water combined?

thanks!

 

[Bobby_M]

3 x 68 = 204 gravity units / 5 gal = ~ 41 or 1.041

 

[phishfood]

Another formula for the back of my brew log. Thanks!

 

[BigB]

Hopefully I am not hijacking this thread, but on the same lines, I am curious if the result "1.041" would be measured if the OP had simply added the 2 gallons of water and then took the measurement?

 

[Chombo]

thanks bobby!

bigb, im not sure, my target gravity was 45 so i guess it would be pretty close

 

[HomelessWook]

I'll have to jot that down.

 

[ajf]

Hopefully I am not hijacking this thread, but on the same lines, I am curious if the result "1.041" would be measured if the OP had simply added the 2 gallons of water and then took the measurement?

Probably not, but just because simply adding the water and taking the measurement wouldn't mix things up well enough. If the water was added, and the diluted wort was stirred until the wort and the water was completely homogeneous, then the result would be 1.041.

-a.

 

[Revvy]

Most brewing software like beersmith has a dillution tool that does this for you. I use it all the time.

 

[BigB]

Ok, just curious because I can only do partial boils and I take my hydrometer readings after I add the last of the water. My readings are always higher than the recipes specify.

 

[Revvy]

Ok, just curious because I can only do partial boils and I take my hydrometer readings after I add the last of the water. My readings are always higher than the recipes specify.

It's a pretty common issue for ANYONE using extract and then topping off with water (and that includes partial mashes) to have an error in reading the OG...In fact, it is actually nearly impossible to mix the wort and the top off water in a way to get an accurate OG reading...

Brewers get a low reading if they get more of the top off water than the wort, conversely they get a number over if they grabbed more of the extract than the top off water in their sample.

When I am doing an extract with grain recipe I make sure to stir for a minimum of 5 minutes (whipping up a froth to aerate as well) before I draw a grav sample and pitch my yeast....It really is an effort to integrate the wort with the top off water...This is a fairly common new brewer issue we get on here...unless you under or over topped off or the final volume for the kit was 5 gallons and you topped off to 5.5, then the issue, sorry to say, is "operator error"

it doesn't matter what your reading was.....the "real reading" in an extract batch is what it said it would be in the recipe or beersmith....Whether or not you mixed it up enough before you took the reading it mixed itself up fine during fermentation.

So unless you had a final volume a gallon or so higher than 5 gallons....you recipe will be fine and at the OG it was supposed to be,

I bet your OG is EXACTLY what it is supposed to be.

And during fermentation the wort and water will mix up just fine on it's own.

 

[BigB]

Thanks Revvy, Makes sense.

 

[ajf]

Wort is heavier than water. If you add water to the wort, you will have stratification where the heavier wort is at the bottom of the fermenter, and the lighter water is at the top. If you take the sample from the top, you will get a low gravity reading. If you take the sample from the bottom, you will get a high gravity reading. As Revvy said, you can mix it up well, but it is surprisingly difficult, and you need to make a conscious effort to stir vertically, mixing the top with the bottom. The good news is, that the yeasts do all the necessary mixing during fermentation, so when it comes time to get the final gravity stratification is not an issue.

-a.