Post boil gravity - Home Brew Forums
Register Now For Free!

Home Brew Forums > Home Brewing Beer > Brew Science > Post boil gravity

Thread Tools
Old 10-15-2009, 05:55 PM   #1
Limited Visibility
Feb 2008
North Phoenix, AZ
Posts: 579

Not sure if this would be the correct area for this. But I recently just made a 2.5 gallon batch of a stout. And I had a pre-boil gravity of 1.050 with 3.5 gallons of water. And by the end of the boil I had my 2.5 gallons, but I forgot to take a gravity reading before I pitched my yeast.

Is there any general sort of estimation of gravity increase from boil off? Would anyone like to take a guess at what my gravity would have been?
Friendship is like peeing on yourself: everyone can see it, but only you get the warm feeling that it brings.

Reply With Quote
Old 10-15-2009, 07:27 PM   #2
SpanishCastleAle's Avatar
Jan 2009
Central Florida
Posts: 4,345
Liked 37 Times on 37 Posts

Just multiply your measured preboil gravity (in 'points') by the ratio of the volumes. But this assumes all the liquid gets into the fermenter.

50 * 3.5/2.5 = 70. So assuming no losses your gravity should be around 1.070. You will have a very small loss due to wort absorbed by the hops (or any other lost/spilled wort) so it might be tiny bit lower than that but not much. I'd guess you were at 1.068-1.069. Again, assuming all the wort except for those tiny losses mentioned made it into the fermenter.
Early brewers were primarily women, mostly because it was deemed a woman's job. Mesopotamian men, of some 3,800 years ago, were obviously complete assclowns and had yet to realize the pleasure of brewing beer.- Beer Advocate

Reply With Quote
Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Calculating wort expansion along with pre and post boil boil volumes greggor General Techniques 4 10-23-2009 12:01 PM
how can I determine post-boil gravity from a pre-boil gravity reading? snailsongs General Techniques 5 03-05-2009 04:42 PM
Post boil gravity doesn't match post boil gravity Kaiser All Grain & Partial Mash Brewing 17 02-10-2009 04:07 PM
Technique for determining pre boil gravity with a split boil...? hagbardceline All Grain & Partial Mash Brewing 3 10-17-2008 04:31 AM
Pre-boil efficiency higher than post-boil??? bearymore All Grain & Partial Mash Brewing 4 09-18-2008 07:25 PM

Forum Jump