Home Brew Forums > Home Brewing Beer > General Beer Discussion > is there a way to calculate how much water I need to evaporate to reach my OG?
Reply
 
Thread Tools
Old 06-16-2013, 11:19 PM   #1
Elysium
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2013
Location: Madrid, Spain
Posts: 1,187
Liked 21 Times on 21 Posts
Likes Given: 171

Default is there a way to calculate how much water I need to evaporate to reach my OG?

I always check the amount of wort I got before the boil and check the gravity before the boil.

But I am wondering if there is a way ((if there is an equation) to calculate how much I need to boil off to get to my required OG gravity.

I understand that I have wort shrinkage, loss in equipment and trub...but that is irrelevant. I'd just like to know how much liquid I need to boil off to get to my desired OG. There must be an equation.

Thanks.


Elysium is offline
 
Reply With Quote
Old 06-16-2013, 11:22 PM   #2
Revvy
Post Hoc Ergo Propter Hoc
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Revvy's Avatar
Recipes 
 
Join Date: Dec 2007
Location: "Detroitish" Michigan
Posts: 40,816
Liked 2883 Times on 1701 Posts
Likes Given: 3514

Default

In beersmith it is called the boil off tool. There looks to be some free calculators here.


__________________
Like my snazzy new avatar? Get Sons of Zymurgy swag, here, and brew with the best.

Revvy's one of the cool reverends. He has a Harley and a t-shirt that says on the back "If you can read this, the bitch was Raptured. - Madman

I gotta tell ya, just between us girls, that Revvy is HOT. Very tall, gorgeous grey hair and a terrific smile. He's very good looking in person, with a charismatic personality... he drives like a ****ing maniac! - YooperBrew
Revvy is offline
 
Reply With Quote
Old 06-17-2013, 05:44 AM   #3
IL1kebeer
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2013
Location: Inland Empire, CA
Posts: 723
Liked 90 Times on 77 Posts
Likes Given: 7

Default

Multiply your preboil og by your preboil volume. that will give you a your total gravity points. divide that by your target og then you will get the voluime that you need to shrink your wort down to after boil and cooling losses.

Example:

Preboil gravity = 1.055
Preboil volume = 6.5 Gallons
Target OG = 1.065

55 (preboil gravity) * 6.5 (preboil volume) = 357.5 total gravity points

357.5 (total gravity points) / 65 (target OG) = 5.5 gallons

6.5 (preboil volume) - 5.5 (volume after boil and cooling) = 1 gallon

Keep in mind that this doesn't take into account any losses from trub or plate chilllers etc.

And also, like Revvy said, there are many different programs out there that will do these calculations for you.
IL1kebeer is offline
Elysium Likes This 
Reply With Quote
Old 06-18-2013, 08:47 PM   #4
brewinginnc
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2012
Posts: 293
Liked 39 Times on 24 Posts

Default

Gravity calculator at onebeer.net
brewinginnc is offline
 
Reply With Quote
Old 06-19-2013, 04:54 PM   #5
Elysium
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2013
Location: Madrid, Spain
Posts: 1,187
Liked 21 Times on 21 Posts
Likes Given: 171

Default

Quote:
Originally Posted by IL1kebeer View Post
Multiply your preboil og by your preboil volume. that will give you a your total gravity points. divide that by your target og then you will get the voluime that you need to shrink your wort down to after boil and cooling losses.

Example:

Preboil gravity = 1.055
Preboil volume = 6.5 Gallons
Target OG = 1.065

55 (preboil gravity) * 6.5 (preboil volume) = 357.5 total gravity points

357.5 (total gravity points) / 65 (target OG) = 5.5 gallons

6.5 (preboil volume) - 5.5 (volume after boil and cooling) = 1 gallon

Keep in mind that this doesn't take into account any losses from trub or plate chilllers etc.

And also, like Revvy said, there are many different programs out there that will do these calculations for you.
Thanks a lot for the equation. I have already made a calculator from it using an excel file.

there is one thing I dont understand......

I started with a 1.032 pre-boil gravity and 5.81 gallons of wort. I wanted to reach 1.053....after the boil I was left with 0.8 gallon of trub and 1.5 gallons of wort boiled off. According to the calculator..I should have boiled off 2.3 gallons of wort to get to 1.053, but I got there with 1.5 gallons.
Is it because my system is not flawless or is this because the turb left from the grains doesnt really affect the final gravity. I guess it hardly has water, but mainly the dirt left over form the grains.


Elysium is offline
 
Reply With Quote
Reply


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to calculate Sodium from water analyzis spura Brew Science 6 03-15-2012 06:32 PM
How do you calculate how much water you lose during the boil? biggrizzly Extract Brewing 12 01-05-2012 09:37 PM
Any software reach water temps correctly? Beezer94 All Grain & Partial Mash Brewing 11 05-17-2010 05:51 PM
Adding water to reach 5 gallon question. jimmywit Beginners Beer Brewing Forum 7 03-21-2010 05:00 PM
How do I calculate Water Needed for Sparge? RonRock All Grain & Partial Mash Brewing 14 01-11-2009 04:12 AM


Forum Jump

Newest Threads

LATEST SPONSOR DEALS