Immersion coil vs jacket

[effeffe]

I am considering stainless steel conicals for common homebrewing sizes, say in the 5-20 gal range; some use immersion cooling coils (like Ss Brewtech and Spike Brewing) and some are jacketed (like Glacier, Stout, and Brewers Hardware).

At these sizes, what are the differences? Besides price (jacketed is clearly much more expensive) and cleaning (I guess the coil needs some attention), I am curious about cooling performances.

Is temperature stratification a thing at the homebrewing scale? If so, do jacketed conicals solve the issue? Unfortunately, I could not find any tests about this online.
Is there some other difference in how the cooling works with the two systems?
Are glycol jackets more relevant at, for instance, 20 gal rather than 7 gal?

I read some (admittedly few) conical owners here and there complaining about (sometimes considerable) temperature stratification among different zones with immersion coils, especially when crash cooling. I don't know enough of the physics and engineering behind it to be sure whether one approach is superior to the other. I don't know whether jacketed conicals are usually bigger in size because that kind of system is useless at the homebrewing scale, or just because they would be too expensive for our market. Possibly both.

 

[Jag75]

I can only speak on Spike. I have a cf5 with the TC. I use a DIY chiller w/gylcol. I transfer my wort at about 90 degrees. Within 15 minutes or so it's at pitching temp . It holds to the desired temp on the button.

 

[logdrum]

I recently upgraded to a SS conical & had similar questions. I went with the immersion coil/heat wrap because initiating a diacetyl rest w a jacketed tank seemed like too much of a headache to me. Id need a separate heated bath (which could just be a cooler filled w water & an aquarium heater) but then what to do about the cross connection. Probably doable w some solenoid controlled check valves, but again, too much of a headache for me at this point. On top of that, the size I need is out of stock @ Brewers Hardware.

 

[Tom R]

I have a BH jacketed fermenter which is heated or cooled as necessary with a DIY glycol chiller. A heating element in the glycol heats for ales in wintertime and for the diacetyl rest. It shares the same reservoir as the A/C. No extra tanks, no valves.
Works great. I've run it from 18F-70F, no issues.

 

[daveerickson]

I have a BH jacketed fermenter which is heated or cooled as necessary with a DIY glycol chiller. A heating element in the glycol heats for ales in wintertime and for the diacetyl rest. It shares the same reservoir as the A/C. No extra tanks, no valves.
Works great. I've run it from 18F-70F, no issues.

How cold can you get your beer? It seems some immersion chillers struggle under 40, and I'm wondering if the jacket does as well.

 

[logdrum]

I have a BH jacketed fermenter which is heated or cooled as necessary with a DIY glycol chiller. A heating element in the glycol heats for ales in wintertime and for the diacetyl rest. It shares the same reservoir as the A/C. No extra tanks, no valves.
Works great. I've run it from 18F-70F, no issues.

But only one fermenter at a time, right?

 

[Vale71]

At these sizes, what are the differences? Besides price (jacketed is clearly much more expensive) and cleaning (I guess the coil needs some attention), I am curious about cooling performances.

Usually jacketed fermenters have much larger exchange surfaces than ones with a coil, which means greater cooling performance and a reduced tendency to ice formation. The smaller surface of the coils means that you'll need to run your glycol at a lower temperature with increased risk of ice formation, thus limiting your attainable lowest beer temperature to quite a few degrees short of actual beer freezing temperature. Jacketed fermenters usually have better insulation as well, leading to less condensation forming on the outside as well as a reduction in the power requirements, so that you can either use a smaller chiller or run more fermenters on the same chiller before it's maxed out.
Stratification can happen in our fermenters especially if you have a combination of a limited exchange surface and poor external insulation. Areas that are in direct contact with the heat exchanger will tend to be cooler whereas other areas will tend to be warmer due to poor insulation.

 

[Tom R]

"How cold can you get your beer?"

I don't know. I've had it down to 31F, but usually keep it 32-33 when cold crashing.

 

[Tom R]

But only one fermenter at a time, right?

Yes, just one. It's 15 gal, and I'm the only beer drinker in the household, so I won't be needing more.

 

[logdrum]

Yes, just one. It's 15 gal, and I'm the only beer drinker in the household, so I won't be needing more.

That’s a nice solution,tho[emoji1360]

 

[daveerickson]

"How cold can you get your beer?"

I don't know. I've had it down to 31F, but usually keep it 32-33 when cold crashing.

Awesome, that's what I was hoping for. Thank you.

 

[effeffe]

Usually jacketed fermenters have much larger exchange surfaces than ones with a coil, which means greater cooling performance and a reduced tendency to ice formation. The smaller surface of the coils means that you'll need to run your glycol at a lower temperature with increased risk of ice formation, thus limiting your attainable lowest beer temperature to quite a few degrees short of actual beer freezing temperature. Jacketed fermenters usually have better insulation as well, leading to less condensation forming on the outside as well as a reduction in the power requirements, so that you can either use a smaller chiller or run more fermenters on the same chiller before it's maxed out.
Stratification can happen in our fermenters especially if you have a combination of a limited exchange surface and poor external insulation. Areas that are in direct contact with the heat exchanger will tend to be cooler whereas other areas will tend to be warmer due to poor insulation.

Comparing exchange surfaces makes sense. I was bored so...

The Spike CF10 is 17" wide and 35" height, which is 0.43 and 0.89 in meters (sorry, can't handle imperial units). I think this includes ports and stuff; looking at the pictures on the website, I'll say the cylindroconical section actually full of beer is around 0.35 large and 0.50 m high, which makes some sense I guess.

Let's assume the conical and the cylindrical parts have the same height for simplicity. That should give a lateral surface area of about 0.27 m2 for the cylinder and a 0.17 m2 for the cone, around 0.44 m2 total.

The CF10 coil tube is 3/8" ID, so I guess 1/2" OD, 0.0127 m. The circumference is then about 0.04 m, which multiplied by the length of the tube would give the coil surface area.

0.04x = 0.44

Matching the jacket surface area would require 11 meters of coil tube.

Let's say the coil is 0.1 m large (it looks pretty small from the pictures on the website), which gives a circumference of 0.314 m. To make 11 m of tube 35 circles are needed, which gives a height of 0.44. There is some space in between, say as large as the tube itself, so that would be doubled, and is way more than what could fit in the conical.
Still, if I got the math right, it does seem possible to have a coil design reaching the break-even point.

Other factors may be relevant though, like exchange metal thickness and how is the exchange surface distributed in the wort, and possibly something more I am not thinking of... a test with temperature probes in different zones would be interesting.

 

[Vale71]

A coil with 35 windings would give that height only if it were tightly packed. This would unfortunately make it a nightmare from a cleaning/sanitation point of view. A loosely coiled tube (let's say a minimun of 3 centimeters between coils) would then be too tall to fit in the fermenter.

 

[daveerickson]

Interesting analysis, I hadn't considered there could be a crossover point regarding surface area. However, I think there are 2 other factors beyond surface area that impact the cooling ability.

Coils can freeze up at the current surface area/density. You can't get a more distributed surface area than the outside of the vessel.

An insulated jacket should better protect against thermal losses to the environment. This in addition to the surface area increase had me expecting jacketed conicals to more easily drop temp.

Of course, they are also more expensive, so even if they can perform better it may not be worth the cost.

 

[augiedoggy]

I am considering stainless steel conicals for common homebrewing sizes, say in the 5-20 gal range; some use immersion cooling coils (like Ss Brewtech and Spike Brewing) and some are jacketed (like Glacier, Stout, and Brewers Hardware).

At these sizes, what are the differences? Besides price (jacketed is clearly much more expensive) and cleaning (I guess the coil needs some attention), I am curious about cooling performances.

Is temperature stratification a thing at the homebrewing scale? If so, do jacketed conicals solve the issue? Unfortunately, I could not find any tests about this online.
Is there some other difference in how the cooling works with the two systems?
Are glycol jackets more relevant at, for instance, 20 gal rather than 7 gal?

I read some (admittedly few) conical owners here and there complaining about (sometimes considerable) temperature stratification among different zones with immersion coils, especially when crash cooling. I don't know enough of the physics and engineering behind it to be sure whether one approach is superior to the other. I don't know whether jacketed conicals are usually bigger in size because that kind of system is useless at the homebrewing scale, or just because they would be too expensive for our market. Possibly both.

I have both coils in some conicals and jackets on others (I either used blue discharge hose wrapped around the outside and then a jacket of 2 layers of foil bubble wrap over that or the cool zone velco jacket and a ss brewtech conical with the coil and extension as well as 4 110 gallon plastic conicals with the coils inside (50ft 1/2" stainless)
in my case the jackets are LESS expensive by far...

I MUCH prefer the jackets.. way easier to clean the conicals and they just work better. they also insulate better.

For my brewpub, I did just order 3 jacketed (and insulated) 3.5bbl unitanks from sungood so I'll have some true comparisions on a real insulated full stainless jacketed tank soon.

BTW there are pics of my conicals and jackets in my build thread below. I use simple heat wrap on the lower cone part of my jacketed conicals since the heat rises its the better place for it anyway

 

[Bad Bubba]

I have both coils in some conicals and jackets on others (I either used blue discharge hose wrapped around the outside and then a jacket of 2 layers of foil bubble wrap over that or the cool zone velco jacket and a ss brewtech conical with the coil and extension as well as 4 110 gallon plastic conicals with the coils inside (50ft 1/2" stainless)
in my case the jackets are LESS expensive by far...

I MUCH prefer the jackets.. way easier to clean the conicals and they just work better. they also insulate better.

For my brewpub, I did just order 3 jacketed (and insulated) 3.5bbl unitanks from sungood so I'll have some true comparisions on a real insulated full stainless jacketed tank soon.

BTW there are pics of my conicals and jackets in my build thread below. I use simple heat wrap on the lower cone part of my jacketed conicals since the heat rises its the better place for it anyway

Can you lager with the cool zone jackets if you are using glycol?

 

[etk29321]

I agree with augiedoggy. Jackets are much easier to clean and no matter which way you go, insulation is key. The issue I have with most of the really nice looking conicals on the market is they have little to no insulation. Even if my chiller can keep up, they sweat like crazy in our humid air here.

I modified an older blichmann conical with 25ft of copper tubing and then covered it in the foil bubble wrap insulation. That was a really cheap option for me since I repurposed an old immersion wort chiller. I also have one of the cool zone jackets I use around a corny keg. The cool zone jacket works, but I'm planning to move to a copper coil for the keg too just because I can secure it in place and insulate it better.

 

[augiedoggy]

Can you lager with the cool zone jackets if you are using glycol?

yes