Originally Posted by skunker
Contrary to what the Williams Brewing website states, copper would transfer heat better.
I have question about that. I know everybody has read that copper is better at heat transfer a thousands times but I am looking for clarification on it.
Yes copper does get hotter or cooler faster (more efficiently) than SS but as far as accomplishing your end goal of wort chilling is that really what you want?
In an immersion
chiller, I would think copper would be better as you are submerging it in a body of hot wort during the boil (making it hot) and then running water thru it in order to change the temperature of the chiller. The faster (more efficiently) you change the temperature of the chiller the faster the wort it is submerged in will cool.
But in an counter flow
chiller, you are doing the opposite. You are releasing a small amount of wort into the chiller which already has been cooled by running water thru it. The wort touching the cool surface of the chiller makes the wort cooler...so in a counter flow, wouldn't you want the chiller to resist getting warmer by exposure to the hot wort...wouldn't you want it to be sluggish in absorbing (transferring) the heat from the hot wort? Wouldn't something that is poor at absorbing the heat from the wort and maintain the cool that it has been set at be better so the next amount of wort that comes in contact with the chiller surface be touching a still cool surface?
Even though these chillers are really heat exchangers, you aren't really trying to exchange temperature but instead maintain one side (the cold side thru flowing cool water thru it) and pull the wort towards that side.
Since it is easier to change the temperature of copper it is easier to equalize the temperature between the hot and cold side in copper, when what you are really trying to maintain the cool surface of the chiller as long as possible so the equalization is averaged out to a lower temperature.
This is why I always thought that plate chiller are made of SS and NOT copper.
Again, I know we have all read that copper is "better at heat transfer" so I am looking to have this explained by someone that really knows. If anybody can explain WHY copper would be better in a CFC than stainless I would like to have it explained. I realize copper is also easier to work with and that' why most DIYers use it but is it really the best material for a CFC?