Does it matter which end of Immersion chiller is inlet/exit?

[jetmac]

Does it matter if water enters the top and works its way down then out or is it better to have cold water start at the bottom and work its way up and out?

 

[ChuckO]

Short answer, NO.

Heat transfer will be the same either way, as the temperature differential from top to bottom of the wort will be small. Of greater importance is to keep the wort moving so that a localized cool area won't form around the coil.

 

[jsb]

Which begs the question "how do you keep the wort moving without keeping the trub in suspension?" For me, I lightly swirl the wort periodically in the first part of the chill. However, as I get closer to the end, I am hesitant to do so as there is so much cold break I want it to settle out before I transfer to the fermenter.

Due to the size of my pot, my likely too small immersion chiller, and that I am doing 6-gallon boils, I get an natural thermal layer between the top of the chiller and the top of the wort. The bottom half is ~75 degrees and the top half is 110+. You can feel a distinct break with your hand on the outside of the pot. I tried to combat this by making sure the cold water came in at the top of the chiller so that it had the greatest cooling capacity in the hottest part of the wort, but it did not change much.

What I have started doing now, is once the thermal layer is created, I begin sloooowly draining my pot from the bottom drawing the warmer wort down over the chiller without disturbing the trub. This actually shortened my overall chilling time as well, without keeping all the trub in suspension.

I do have to say I wonder if I am doing it right, but it works for me.