Wort Chilling Question

[SwooshBrew]

My brewing partner and I are looking to create a copper coil wort chiller from scratch rather than shelling out the money to buy one pre-made. We’ve seen it done before and it looks pretty straight forward. It also helped that we acquired 50 feel of copper for a great deal. Now for my question: The copper tubing is 3/8 in diameter, will 3/8 be large enough to adequately chill 15ish gallons of wort in our brew keg? Thoughts?

First post on the forum, we’re new, crazy about home brew and looking forward to future discussions.

Thanks!

 

[dmcoates]

Depends.

I use 50' of 3/8 to coil my 10gal batch's it only takes about 15-20min. However i live in Alaska and my water comes out of my well @38F or so. If you have cold ground water 3/8" will work but if not you will need 1/2"

BTW if you plan to Do more than 10gal batch's you will need more than a 15gal keg. To do 10gals you need to boil 12.5 gal or so and thats about all you can boil in a keg without it boiling over.

 

[SwooshBrew]

Thanks!

Living in Oregon, our water temp is pretty cold...so I think we're good in that department.

Our brewing capacity is roughly 10gal and you're right, we will need to boil around 12.5 in order to get 10gal. We're brewing in a keggle.

 

[wolverinebrewer]

Depends.

If you have cold ground water 3/8" will work but if not you will need 1/2"

I disagree. It's not a matter of not cooling at a certain temp. It's more of how fast the water goes through the coil. Ideally, you want the exit water to be the same temperature as the wort at the fastest speed. If the outlet water is cooler than the wort, the system is not as efficient because the water that went through the coil too fast and did not pull out the maximum amount of heat. 3/8" will work no matter what your water temperature is but you just need to slow it down. If water conservation doesn't matter to you, then crank up the faucet and let it rip.
I use a homemade 5/8" od. chiller hooked to a 5/8" garden hose and I run the water pretty slow. Sending a larger volume of water through at a slower speed maximizes the amount of heat extraction which is key to getting the wort temp down through that critical bacteria zone. I do not worry about water useage so I just keep the speed at a point where it is slightly cooler than the wort so then I know that the wort cannot be cooler any faster with my system.

I hope that makes sense. Your chiller will work but you just need to play with it to get it to where it works best for your system.

 

[dmcoates]

I disagree. It's not a matter of not cooling at a certain temp. It's more of how fast the water goes through the coil. Ideally, you want the exit water to be the same temperature as the wort at the fastest speed. If the outlet water is cooler than the wort, the system is not as efficient because the water that went through the coil too fast and did not pull out the maximum amount of heat. 3/8" will work no matter what your water temperature is but you just need to slow it down. If water conservation doesn't matter to you, then crank up the faucet and let it rip.
I use a homemade 5/8" od. chiller hooked to a 5/8" garden hose and I run the water pretty slow. Sending a larger volume of water through at a slower speed maximizes the amount of heat extraction which is key to getting the wort temp down through that critical bacteria zone. I do not worry about water useage so I just keep the speed at a point where it is slightly cooler than the wort so then I know that the wort cannot be cooler any faster with my system.

I hope that makes sense. Your chiller will work but you just need to play with it to get it to where it works best for your system.

Yes i do agree with you to a point. I just blast water thru my chiller and in 15min i am down to 65 ish. I believe that 38F water running thru the chiller cools my wort faster than if i had 55F water running thru it.

Many poeple here use 1/2" and it takes them the same time to cool it does me with 3/8". Its like if you put your kettle in the bath tub to cool with cool water in the tub or ice water in the tub. What one will cool faster

Here is a Quote for HBT Wiki

"The colder the input water, the more potential it has to pull heat out of the wort. In some cases, tap water is not cold enough to cool the wort fast enough to be practical. In this case, the brewer has two options. Tap water may be fed through a pre-chiller before being fed through the chiller; the most common type of pre-chiller is essentially an immersion wort chiller immersed in an ice bath. Another option is to pump icewater directly through the chiller (using an aquarium pump if necessary) rather than tap water."

 

[BendBrewer]

Thanks!

Living in Oregon, our water temp is pretty cold...so I think we're good in that department.

Where abouts?

 

[frankstoneline]

I disagree. It's not a matter of not cooling at a certain temp. It's more of how fast the water goes through the coil. Ideally, you want the exit water to be the same temperature as the wort at the fastest speed. If the outlet water is cooler than the wort, the system is not as efficient because the water that went through the coil too fast and did not pull out the maximum amount of heat. 3/8" will work no matter what your water temperature is but you just need to slow it down. If water conservation doesn't matter to you, then crank up the faucet and let it rip.
I use a homemade 5/8" od. chiller hooked to a 5/8" garden hose and I run the water pretty slow. Sending a larger volume of water through at a slower speed maximizes the amount of heat extraction which is key to getting the wort temp down through that critical bacteria zone. I do not worry about water useage so I just keep the speed at a point where it is slightly cooler than the wort so then I know that the wort cannot be cooler any faster with my system.

I hope that makes sense. Your chiller will work but you just need to play with it to get it to where it works best for your system.

I disagree (someone with a greater grasp on thermo can comment and explain if this is misinformation) but essentially a cooling system is a convection-like system with a barrier between the two liquids (edited to add: ideally the barrier between the two fluids would be invisible which is indeed a complete convection system by my understanding), so the most tangible model (in my eyes, again correct if i'm wrong) would be newton's law of cooling, which relates the rate of heat loss in a body to the temperature of it's surroundings. In this case the ratio's being the heat of the water in the chiller vs the hot wort. To maximize cooling you would want to maximize the temperature difference, because as equilibrium is approached (the heat of water coming out of the cooler vs wort temp being ~1) then the heating ability of the water is drastically reduced. thus, moving water quickly through the cooler maintains an overall greater difference in temperature and more rapid heat shift in the kettle.
All of this is supposition based on a pretty minimal background in thermo and some personal observation in realms other than brewing.

 

[wolverinebrewer]

I disagree (someone with a greater grasp on thermo can comment and explain if this is misinformation) but essentially a cooling system is a convection-like system with a barrier between the two liquids (edited to add: ideally the barrier between the two fluids would be invisible which is indeed a complete convection system by my understanding), so the most tangible model (in my eyes, again correct if i'm wrong) would be newton's law of cooling, which relates the rate of heat loss in a body to the temperature of it's surroundings. In this case the ratio's being the heat of the water in the chiller vs the hot wort. To maximize cooling you would want to maximize the temperature difference, because as equilibrium is approached (the heat of water coming out of the cooler vs wort temp being ~1) then the heating ability of the water is drastically reduced. thus, moving water quickly through the cooler maintains an overall greater difference in temperature and more rapid heat shift in the kettle.
All of this is supposition based on a pretty minimal background in thermo and some personal observation in realms other than brewing.

You could be right. Like you, I'm not a thermo dynamics guy. I wasn't really thinking of the fact that the quicker you are bringing in the cooler water, the more beneficial it would be in cooling.
So, maybe its true that no matter how fast you run the water through, it is always cooling making it impossible to "waste" water.

 

[frankstoneline]

You could be right. Like you, I'm not a thermo dynamics guy. I wasn't really thinking of the fact that the quicker you are bringing in the cooler water, the more beneficial it would be in cooling.
So, maybe its true that no matter how fast you run the water through, it is always cooling making it impossible to "waste" water.

I think it really becomes a compromise between water use vs cooling times. I'd be interested to see how much cooling time shifts based on volume of water pushed through tubes, however I'm lazy and not up to undertaking the project atm.

 

[wolverinebrewer]

I think it really becomes a compromise between water use vs cooling times. I'd be interested to see how much cooling time shifts based on volume of water pushed through tubes, however I'm lazy and not up to undertaking the project atm.

I hear you. I think that out of all of the money I've spent in this hobby, the $48 chiller ranks up there towards the top. It's invaluable.

I guess I don't need to know how it works best, just that it works.

 

[SwooshBrew]

We're in NE Portland. Bend I see, NICE! I would imagine this site pulls a hefty NW crowd?

Where abouts?

 

[beerloaf]

That $48 chiller everyone keeps talking about costs $75 here in our local brewing store. So I'm tempted to build one as well because I know I can make one for well under that. It took me for ever to cool the wort on my last batch and I will definately use a chiller next time.

 

[wolverinebrewer]

That $48 chiller everyone keeps talking about costs $75 here in our local brewing store. So I'm tempted to build one as well because I know I can make one for well under that. It took me for ever to cool the wort on my last batch and I will definately use a chiller next time.

Well, the $48 chiller I was talking about couldn't be the one everyone else was talking about because I made my own.

I bought 20' of 5/8" copper from Lowes for $35. I bought 2 small straight pieces to construct the upright portion, 4 elbows, and garden hose fittings for about $13. It is very easy to build but if you use additional pieces like I did, you will need to know how to solder.
I had to build mine because you can't buy them with 5/8" pipe.
There was a thread on here yesterday about very cheap copper prices from an online source. I would check that out.

 

[cwheel]

Yeah, you want the fluid coming out of your wort chiller to be as cold as possible, as it means the copper is as cold as possible and thus the maximum amount of heat transfer is occuring between the hot wort and the copper. But there are other factors that are generally more important, such as making sure the speed of the fluid in the chiller is turbulent (not laminar) as well as making sure to circulate your wort to move the cooler fluid in contact with the copper away from the coil so that warmer worth can replace it and increase the overall heat transfer.

In a pinch, I've cooled a 3 gallon batch of wort down to 70 degrees within 15 minutes just by using an ice bath. But to do that, you have to constantly stir both the wort as well as the ice bath surrounding the pot, and make sure you add ice as necessary.

 

[SoonerDoc]

I made one with 50' of 1/2" copper. I got 5 gallon boil down to 68 degrees in 6 1/2 minutes.
No point, I just wanted to brag.

 

[mcberry]

To answer the original question - yes 50' of copper will be able to cool 15 gallons of wort. The biggest factors in time are how much you are circulating the wort, the length of copper, and the input temperature of your water.

You may see small differences by adjusting the tube diameter and water flowrate, as well.

Just focus on circulating the wort while cooling and you'll be all set and thrilled with the fact that you will never need to cool via ice bath again.

 

[william_shakes_beer]

I've done some pedestrian thinking on the matter, and seems to me if you fill a sink with ice water and push that through the chiller with a drill pump you'd have the best of both worlds.

 

[JasonAle]

I have a heat exchanger in the tank where the pump is from a fish tank. A very good thing. Cools 20 liters of water in 20 min

 

[cwheel]

I've done some pedestrian thinking on the matter, and seems to me if you fill a sink with ice water and push that through the chiller with a drill pump you'd have the best of both worlds.

That's my exact setup!

 

[integrator]

yes it will work. If you already bought the stuff, go for it.
I use 50' of 1/2" copper and it cools 10 gallons in about 15 minutes. Yours may take longer but it will still do the job nicely.

 

[dmcoates]

yes it will work. If you already bought the stuff, go for it.
I use 50' of 1/2" copper and it cools 10 gallons in about 15 minutes. Yours may take longer but it will still do the job nicely.

How cold if your water? Just curious, thats how long it takes me to cool 10gal with 50' of 3/8"

 

[integrator]

How cold if your water? Just curious, thats how long it takes me to cool 10gal with 50' of 3/8"

well i'm not is alaska!

I'll measure it sometime. the spicket does come from a line that runs through the basement so it's probably a little warmer than it should in the winter. Given it helps a lot in the summer.
I've not timed it to the exact second/minute. I know its never taken more than 15. Prob in the 12-15 min range.

 

[SwooshBrew]

Thanks all for the input, every bit I found helpful and it answered my question perfectly. It’s my first question of many I’m sure many! I especially enjoyed how nerdy the topic became after only a few posts...that’s when you know you’ve come to the right place.

I’m so glad to be done with the ice baths…whew!