Coldbreak Brewing HERMS Giveaway!

HomeBrewSupply AMCYL Brew Kettle Giveaway!


Home Brew Forums > Home Brewing Beer > General Techniques > How to Perdict Gravity?
Reply
 
Thread Tools
Old 07-09-2008, 02:54 PM   #1
hagbardceline
Feedback Score: 0 reviews
Recipes 
 
Join Date: May 2008
Location: St. Paul, MN - Minnesota
Posts: 78
Default How to Perdict Gravity?

For my first all grain beer I will be brewing an English Ordinary Bitter. I am using the recipe from John Palmer which includes British Invert Sugar.

Since this is my first all grain I computed my grain bill using 65% eff. My concern is if things go better than that.

I have been reading tons of threads, books, etc about efficiency, all grain techniques and I will be mashing in a cooler with a SS braid.

Since the invert sugar isn't added until the boil I will leave it out if my gravity is high enough - but if it isn't what is the formula for figuring out how much of x substance will give you the gravity addition you want?

I have been looking all over for this but have come up empty handed...

Also one more question I haven't been able to find an answer for: at what point in the mashing and lautering process do you want to take hydrometer readings?

Thanks


hagbardceline is offline
 
Reply With Quote
Old 07-09-2008, 03:16 PM   #2
The Blow Leprechaun
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2008
Location: Rockville, MD
Posts: 602
Liked 4 Times on 4 Posts

Default

Table sugar will add 45 points per gallon per pound, so you have to take that figure and calculate your addition based on wort density. Papazian has a calculation for it, I think.

Or you could sit down with some brewing software, get your numbers to where you're at your current gravity, then slowly add sugar in amounts to the recipe until it hits your target gravity, then add that amount of sugar.

I think the math on this is pretty tricky, so I'd probably do it trial and error with the software.
The Blow Leprechaun is offline
 
Reply With Quote
Old 07-09-2008, 03:17 PM   #3
Donasay
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2007
Location: Boston
Posts: 1,581
Liked 7 Times on 7 Posts

Default

as soon as your kettle is full take the reading, this gives you your mash efficency. For a 10 gallon boil, if you are going to boil off 2 gallons over an hour, you will have 12 gallons in your brewpot which will be concentraited down to 10 gallons by the end of the boil. Do some simple algebra to figure out how much more concentraited the wort will be. If you are shooting for an og of 1.05 and are going to have the same amount of sugar but only 10/12ths of the liquid you would shoot for a 1.041 pre boil gravity.

I did a horrible job explaining this, but hopefully it makes sense, there are all kinds of pretty formulas in several homebrew books.
__________________
No matter how rich you are, you can still only drink 16 or 17 liters of beer a day.

Quote:
Originally Posted by quixotic View Post
The true definition of an addiction: not stopping even when a dog is having his way with you.:D
http://www.solutionsinmetal.com/
Donasay is offline
 
Reply With Quote
Reply


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Now there's some gravity for you mrbowenz General Beer Discussion 9 06-11-2009 08:57 PM
Starting gravity vs. finished gravity? Q2XL All Grain & Partial Mash Brewing 9 06-04-2009 06:47 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
Specific Gravity? Target Gravity? HalloweenGod General Techniques 6 01-03-2009 07:30 PM


Forum Jump

Newest Threads

LATEST SPONSOR DEALS