Spike Brewing 12.5 Conical Fermenter Giveaway - Enter Now!

 Home Brew Forums > Water Temp Formula

02-03-2010, 03:30 PM   #1
JayInJersey
Feedback Score: 0 reviews
Recipes

Join Date: May 2009
Location: New Jersey
Posts: 600
Liked 1 Times on 1 Posts
Likes Given: 2

 Water Temp Formula

What's the formula to determine how much water at a certain temp to add to x amounts of water at another temp to reach a final temp?

No grains...just water and water

Thanks!

__________________

02-03-2010, 03:51 PM   #2
rocketman768
Feedback Score: 0 reviews

Recipes

Join Date: Feb 2008
Location: Evanston, IL
Posts: 1,086
Liked 22 Times on 19 Posts

If you assume that the two masses of water only transfer heat energy to each other and not to their surroundings, then you assume that the heat energy lost by the hotter water is the same as the heat energy gained by the cooler water.

Q = m*c*(T1-T2)
Is the amount of heat energy required to raise an object with mass "m" and specific heat "c" from temperature "T2" to temperature "T1."

m1*c1*(T_hot - T_f) = m2*c2*(T_f - T_cold)

Where T_hot is the temperature of the hotter object, m1 is the mass of the hotter object, c1 is the specific heat of the hotter object, (T_cold,m2,c2 for the colder object), and T_f is the final equilibrium temperature of both objects.

In your case, c1=c2 since both the objects are water. Reducing the above equation, the final temperature is

T_f = (m1*T_hot + m2*T_cold)/(m1+m2)

02-03-2010, 04:13 PM   #3
JayInJersey
Feedback Score: 0 reviews
Recipes

Join Date: May 2009
Location: New Jersey
Posts: 600
Liked 1 Times on 1 Posts
Likes Given: 2

I swear...my brain hurts reading over all the Electrical stuff, but this just makes sense to me.

But just to make sure I'm not making a too long away from Algebra error...

If I have 4 Gallons of 180* water and want to get the water to 155* adding ~1Gallon of 60* water should do it right?

__________________

Last edited by JayInJersey; 02-03-2010 at 04:30 PM.

02-03-2010, 07:52 PM   #4
rocketman768
Feedback Score: 0 reviews

Recipes

Join Date: Feb 2008
Location: Evanston, IL
Posts: 1,086
Liked 22 Times on 19 Posts

Quote:
 Originally Posted by JayInJersey If I have 4 Gallons of 180* water and want to get the water to 155* adding ~1Gallon of 60* water should do it right?
Looks right.