How to predict final gravity? Formula? - Home Brew Forums
Register Now For Free!

Home Brew Forums > Home Brewing Beer > General Techniques > How to predict final gravity? Formula?

Reply
 
Thread Tools
Old 03-25-2009, 06:24 PM   #1
Superdave
Recipes 
 
May 2008
Manhattan Kansas
Posts: 121


How do you figure out expected final gravity?

I brewed a couple beers about a week and a half ago. I was just wondering if there was any way to guess what the final expected gravity was.

First batch was an IPA, mashed at 152 deg for 60 min, OG was 1.060, yeast used was Wyeast 1272, American Ale II, attenuation listed at 72-76%. Fermented at 64-65 deg. I pitched a starter made from the yeast in the bottom of a few bottles, so it was a pretty strong pitch. (Quite a bit of sediment by the time it was pitched.)

Second batch was a lager, mashed at 147 or so for 90 min, OG was 1.043, yeast used was Wyeast 2112 (real sure on that), attenuation listed at 67-71%. Fermented around 60 degrees.

Is there some kind of formula to guess what the final gravity will end up being? Thanks!

 
Reply With Quote
Old 03-25-2009, 06:32 PM   #2
Denny
HBT_LIFETIMESUPPORTER.png
Recipes 
 
Jun 2005
Eugene, OR
Posts: 4,871
Liked 681 Times on 489 Posts


There is no accurate way to calculate FG. It depends on the fermentability of your wort, how much yeast you pitch, how healthy it is, and other factors. Some software will give you an estimate based on the yeast's attenuation rating, but that rating is for comparing one yeast to another rather than an absolute indicator of FG. After you brew the same batch a few times, you can start making a guess.
__________________
Life begins at 60....1.060, that is!

www.dennybrew.com

http://www.experimentalbrew.com - "Homebrew All Stars" now shipping!

 
Reply With Quote
Old 03-25-2009, 10:10 PM   #3

I use and enjoy Beersmith, which will give you gravity estimates. You can download a copy and use it during a free trial period to see if you like it. Cheers,

Jim

 
Reply With Quote
Old 03-25-2009, 10:36 PM   #4
Denny's Evil Concoctions
Grande Megalomaniac
HBT_LIFETIMESUPPORTER.png
 
Denny's Evil Concoctions's Avatar
Recipes 
 
Oct 2005
West Kelowna BC, Canada
Posts: 7,733
Liked 67 Times on 53 Posts


While beersmith does gove etimites it does not account for things like mash temps or fermentation temps or use of non-fermentable malts.

That said it does give you a rough idea.
__________________
I may not be an expert, but I did stay at a Holiday Inn Express........ 6 months ago.

http://www.homebrewtalk.com/f39/denn...9/#post1766281

http://groups.homebrewtalk.com/Tapro...ook_Repository

 
Reply With Quote
Reply
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tinseth Formula and Gravity jescholler Brew Science 5 10-21-2009 12:14 PM
Formula For Specific Gravity At Any Temperature Zul'jin Beginners Beer Brewing Forum 8 04-13-2009 07:17 PM
Final gravity keeps going low Matt Up North All Grain & Partial Mash Brewing 2 01-15-2009 08:16 PM
1.049 Final Gravity? fightguy Extract Brewing 22 01-05-2008 07:15 PM
Final Gravity kdsarch All Grain & Partial Mash Brewing 3 11-24-2007 03:15 AM


Forum Jump