Spike Brewing 12.5 Conical Fermenter Giveaway - Enter Now!

Home Brew Forums > Home Brewing Beer > General Beer Discussion > Do barometric pressure changes affect boil temperatrue?

Reply
 
LinkBack Thread Tools
Old 02-24-2011, 06:37 PM   #11
passedpawn
Waste Allocation Load Lifter - Earth Class
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
passedpawn's Avatar
Recipes 
 
Join Date: Apr 2009
Location: ☼ Clearwater, FL ☼
Posts: 18,561
Liked 3177 Times on 1984 Posts
Likes Given: 2699

Default

I think the only thing that might be affected is how well the hop acids are liberated from the hops.

Here, I plotted that formula from above.

__________________
What Would Vermeer Paint?
passedpawn is offline
 
Reply With Quote Quick reply to this message
Old 02-24-2011, 07:58 PM   #12
Hex
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2009
Location: Granite Bay, CA
Posts: 1,042
Liked 20 Times on 20 Posts
Likes Given: 23

Default

According to this, the above chart could accurately be written as hop utilization vs boil temperature.

__________________
Hex is offline
 
Reply With Quote Quick reply to this message
Old 02-24-2011, 08:02 PM   #13
Doog_Si_Reeb
Beer is Good. And stuff!
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
Doog_Si_Reeb's Avatar
Recipes 
 
Join Date: Dec 2006
Location: Albuquerque, NM
Posts: 869
Liked 20 Times on 15 Posts
Likes Given: 18

Default

Quote:
Originally Posted by passedpawn View Post
I think the only thing that might be affected is how well the hop acids are liberated from the hops.

Here, I plotted that formula from above.
I must say, seeing that graphically is a little discouraging. That indicates that I'm only getting about 80% utilization since I'm at 6000 ft. If that's the case, then I would theoretically need to increase my 60 min additions 25% to get the expected IBUs. However, my brews come out pretty good so I probably won't change my additions.

And for the record, water/wort at my house boils at ~202 F. I typically boil off 1 gallon per hour. If I kept my burner cranked, I'd probably boil off twice that amount.
__________________
Uff Da Picobrewery

Primary: BohPils3
Kegged: Vienna Lager, Mánagarmr Stout, Ratatoskr IIPA, Cider
Bottled: Yule Gruit
Doog_Si_Reeb is offline
 
Reply With Quote Quick reply to this message
Old 02-24-2011, 11:00 PM   #14
Hex
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2009
Location: Granite Bay, CA
Posts: 1,042
Liked 20 Times on 20 Posts
Likes Given: 23

Default

boil_temp_vs_abs_barometric_pressure
y (boil temp deg.f)=49.161 * ln (x barometric pressure inches mercury) + 44.932

Equations - Air Density and Density Altitude


Also:

p = 101325 (1 - 2.25577 10^-5 h)^5.25588
where
p = air pressure (Pa)
h = altitude above sea level (m)

__________________
Hex is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Shake the carbination into the Keg - Does it affect Flavor? Griffsta General Beer Discussion 7 09-28-2009 04:57 PM
Adding Gypsum would Affect Flavor? agroff383 General Beer Discussion 9 09-09-2009 10:45 PM
Temperature affect on fermentation beachman General Beer Discussion 10 11-12-2008 11:36 PM
Will Cold Crashing Affect Oak Absorption? Evan! General Beer Discussion 6 04-14-2008 08:53 PM
Lower temps affect attenuation? Bytor1100 General Beer Discussion 2 04-06-2008 08:42 PM