Top off dilemma?

Well I brewed today, yeah, I love it when I get a chance to do that. I'm doing all-grain, this was my 7th batch. I'm using Beersmith to help predict my numbers and am starting to get my system dialed in. I have been having problems getting the post boil volume correct, took time today to work on mash tun dead space and boil loss. I have things setup to shoot for 5.5 gallons post boil, but today I came shorter than I ever have,ended up with 4.75G in the fermenter. I siphon from kettle into primary and try to leave break material in the kettle, today's loss was about 1/2G. So now I can adjust the software to get the end volume better.

Predicted OG was 1.056 with 5.5G in the fermenter, I hit 1.058 with 4.75G in the fermenter. I know there will be more loss in the primary and would like to have more to bottle, but if I top this up with water to 5.5g how will that affect the OG? I'm tempted to just leave it and make the volume adjustments on the next batch, but also want the extra beer in the pipeline. Are there any tools out there that will help me predict the gravity drop if I add 3/4G of water?

I believe Beersmith has a dilution calculator. I've searched in the past for a simple online calculator but never found one... I'd like to know if such a thing exists also.

If you top off with water to 5.5g, you will end up with a gravity of 1.050 ((1.058 - 1.000) * 4.75 / 5.5 + 1.000).
I'd leave it as is, and adjust your efficiency and volumes for the next batch.

-a.

You can easily calculate this by yourself. Think of mixing two parts together that are a) water with 0 gravity and b) wort with gravity 1.058:

58/4.75 = 12.2105 roughly (we're not building a nuclear weapon)

58/5.5 = 10.5454 roughly

(10.5454/12.2105)*58 = 50

ajf said:

If you top off with water to 5.5g, you will end up with a gravity of 1.050 ((1.058 - 1.000) * 4.75 / 5.5 + 1.000).
I'd leave it as is, and adjust your efficiency and volumes for the next batch.

-a.

Click to expand...

I guess his method a lot simpler! But either way same answer

Thanks for the fast responses, much appreciated, I love this forum. I did find a dilution tool in Beersmith, along with a whole set of tools for other calculations I never noticed before. I also like to know the background math. For now I'm going to accept the volume as is and make adjustments in future batches. Didn't really want to ad water to beer that took so much time to make.