Pre-Chiller w/ Smaller Tube Diameter than Immersion Chiller?

Hello All,

I currently have a dinky little 3/8" diameter x 20 foot immersion chiller. Since I'm moving to full-boils, I am planning on building my own copper immersion chiller.

Right now I'm thinking I will go 1/2" diameter x 50 feet. BUT... my hope was to use the dinky immersion chiller I already own as a pre-chiller.

So it would go hose --> 3/8" pre-chiller --> 1/2" chiller

The concern I have is that the pre-chiller with a smaller tube diameter will restrict the flow of water to the 1/2" chiller, thereby making it less effective and not even worth having. I wouldn't have this problem if I went 3/8" x 50 feet on my new chiller...

Anybody ever dealt with this? What should I do?

(1) Ditch the 3/8" pre-chiller entirely and use the 1/2" x 50 feet chiller only?
(2) Use the 3/8" pre-chiller with a 3/8" x 50 foot chiller instead?
(3) Proceed as planned... 3/8" pre-chiller to a 1/2" chiller?

i used to do this all the time with no issue. i just made the water coming into the second chiller, come in on the tube that goes to the bottom of the second chiller, that way the water pumps up the chiller so the chiller is always full of water that way. if that makes any sense.

your design should work fine as-is, but just so you know- the flow rate of a pipe is determined mostly by the point of most restriction. so a 1" coil chiller with only 3/8" fittings is going to flow about as fast as a chiller made entirely from 3/8" pipe. that is not necessarily a bad thing, and all its going to do is make your chiller more efficient (amount of water used per decrease in temperature) as the water is going to spend more time in the coil removing heat from the wort. it will make the overall time it takes to chill slighly higher.