Pre-Chiller vs Post-Chiller

I've been using a CFC with an old IC as a pre-chiller, but I've been wondering if maybe using it as a post-chiller would be even better. We brewed 10 gals yesterday, and even with a pre-chiller and the flow out of the keggle restricted, the wort still ended up at 84'.

Note: I did have some other issues with the pre-chiller fittings restricting flow and coming off and the ice melting before we were done. I'm usually able to get down to 70-75'.

The bad thing about the CFC is that it's a one-shot deal. If it's still too hot, you can't just keep chilling it.

What say you? Is there any difference?

Maybe I should do an experiment to see which one works better.

The CFC is not really a one shot deal. You should have a valve on your kettle to control the flow of hot wort. Additionally, I'd suggest installing one on the water inlet, but you can control flow from the source too. Since you can control the flow of the cool water and the hot wort, you can control the temperature fairly well. Coming out too hot? Slow down the wort flow. Coming out too cool? Decrease the water flow.

I'm not sure what you mean by a post-chiller.

I was using the valve on the kettle to restrict flow. I'm using a wort wizard, though, not a pump, so the level of control is probably not as good.

What I meant by one-shot deal is that once it passes through, then you don't get another shot to continue cooling it.

By post-chiller I mean using the copper coil in the ice bath to run the wort through after it passes through the CFC. Papazian suggests this technique in his book. I think this will be more effective than cooling the water going into the CFC.

There also seems to be opposing forces at work when using a pre-chiller + CFC. It seems like you want the water flowing through the pre-chiller to go slow and have more contact time to chill the water better. But when you lower the flow, then the CFC becomes less effective. With a post-chiller you would only have to worry about the flow of the wort through the CFC + post-chiller. Faster = warmer and slower = cooler.

I'm going to do a test. I bet the post-chiller is more efficient.

That's why I really like a pond pump directly IN the ice water bucket. One less thermal transfer barrier. I suppose another benefit to running a March pump is the chilling doesn't have to be a one shot. You can pump through the CFC and back to the kettle and just stop the chilling water when your wort temp is at pitching.

Yeah, my next purchase is probably a pump. Or maybe a grain mill. Well, I really need to build a kegerator. Damn I need some cash!

I've been considering a post chiller as well. I use a CFC and wort-wizard, so I've been debating on using copper tubing, or rubber tubing between the CFC outlet and the carboy inlet for the wort. The only drawback I can see so far is extra time for sanitation, so I'm trying to think of a better idea, but haven't came up with much. One thing I did consider is a small radiator I already have laying around. Here's a link: http://www.dangerden.com/store/product.php?productid=2&cat=5&page=1

It's never been used, but I'm not sure it would be safe or sanitary to run the wort through it. It's supposedly copper, so could potentially be safe, just not sure. However, if I could run wort through it, I could just drop this radiator into an ice bath inline between the CFC output and Carboy without adding too much extra length in hose to clean. Anyone care to guess if running wort through it would be safe?

If it's all copper, I can't see why it wouldn't work fine. Initial cleaning would be my worry. I think I'd run A LOT of boiling water through it after soaking it in oxyclean overnight.

Lil' Sparky said:

I was using the valve on the kettle to restrict flow. I'm using a wort wizard, though, not a pump, so the level of control is probably not as good.

What I meant by one-shot deal is that once it passes through, then you don't get another shot to continue cooling it.

By post-chiller I mean using the copper coil in the ice bath to run the wort through after it passes through the CFC. Papazian suggests this technique in his book. I think this will be more effective than cooling the water going into the CFC.

Click to expand...

That's all I use for chilling and I have no problem getting to under 70F. I put my 30 ft of copper in a cooler and fill it with ice and water and run the wort through the copper. I keep refilling ice until I'm about half done, then I just put the hose in the cooler and stop using ice.

And you do not want to slow down the velocity of the wort. Heat transfer is dependent on contact and temperature differential, not time.

joejoe1881 said:

And you do not want to slow down the velocity of the wort. Heat transfer is dependent on contact and temperature differential, not time.

Click to expand...

If that were the case, immersion chillers wouldn't work. For that matter, how would you cook steak?