There is some risk the longer you take, but it's overblown in my opinion. I have a 55 gallon drum of water I use to chill, it gets it down below 30C and then I generally let it chill on it's own after that. I think in your case I would suggest using water to get it down to say 60C and then use the slower method, would be more economical?

 

You can transfer the wort to a sanitized fermenter and seal it up and let it cool. If sanitation is good, you’ll be fine letting it cool overnight. Pitch the yeast in the morning.

 

Good old No chill Cube works good too just gotta take into account extended bittering.

 

How much liquid are you cooling? If you're using 50 gallons of water to cool a 5-6 gallon batch in 30 minutes, you're not using the exchanger correctly. I can cool over 6 gallons in lots less than 15 minutes with about 10 gallons of water with an immersion chiller and our cooler tap water temps in Colorado (not necessarily the case in summer). Are you using any type of a coil (in ice bath) to help cool the water running through your exchanger? Pump? Recirc? Valves to slow flow? You could be pushing to fast through your plate. There's ways to get colder liquid through your exchanger or immersion chiller.

 

You could chill much quicker with significantly less water. A coil set in an ice bath pre-plate would definitely help reduce time and water usage. So would valves and slowing the flow a bit. Passing through any heat exchanger to quickly is very inefficient and an energy waste, which basically goes against what a heat exchanger is designed for. Add in a little recirc pump and you would cut your chill water even more.

 

I use an immersion chiller, paired with a swamp cooler pump in a sink full of ice water. Kind of low tech, but will cool a 5 gallon batch to pitching temp in about 15 minutes.
To save on ice, I run with straight tap water at approx 95° until the wort gets to that temp, then add 1 bag of ice to get the last 30°.

 

Ah, so you're actually using an immersion type chiller. My bad on misunderstanding your original post. I automatically assumed a flat plate when you mentioned heat exchanger.
Are you stirring your hot wort with the immersion chiller as you cool? Is is a single coil or multiple coil like the Jaded? https://jadedbrewing.com/collections/frontpage/products/the-king-cobra
The multiple coils and stirring your wort with the chiller make a huge difference.

 

Nope, I'm not the OP. But yes, I stir and agitate.

 

haha. oops!

 

Ice Ice baby! I'm with 222202! I dump my insulated Tun and put about 30 pounds of ice cubes that I have been robbing from the kitchen freezer between brewing. That along with a gallon of water to get the process started gets hooked up to a small submersible pond pump that pumps the ice cold water into the cooling coil and back into the tun. I keep another 10 pounds ready if that doesn't have my 5 to 6 gallons of wort ready at pitching temp inside a 1/2 hour. I would imagine a similar thing would work for your exchanger set up but if it is truly "little" then it may be just completely undersized for what you are doing.

 

It's an Aussie brew idea where you transfer the hot boiling wort into an HDPE cube push all air out and put lid on to chill down over night. You can use the wort the next day or in a week or two when you need to.
Here's my cube it's 23lt most are 20-21 it and square cube shaped hence the name.

 

That's interesting Ben, when you transfer to your fermenter do you decant and leave trub behind? Or dump the works in?

 

Either / or but it does make for trub free transfer pretty easy just like pouring an overly large bottle conditioned beer. I havnt no chilled brew in awhile but the option is there if need be.