Cool Brewing Fermentation Bag

The Homebrew Forum

Help Support The Homebrew Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

MyQul

Chairman of the Bored
Joined
Aug 7, 2013
Messages
17,878
Reaction score
7,119
Location
Royal Hamlet of Peckham. London.
I've never had any fermetation control as I don't have room for either a brewfridge or fermentation chamber so when I saw the fermentation bag I thought it would be the perfect solution for me. So after reading all the positive reviews on Amazon and morebeer I decided to buy one from morebeer.com
http://www.amazon.com/dp/B008EKD7CQ/?tag=skimlinks_replacement-20
http://www.morebeer.com/products/cool-brewing-insulated-fermentation-bag.html

First off let me say this thing is HUGE. The dimensions are approx 21"x 26". My Youngs FV and a blow off rig plus 2L pop bottle (more of ths in a bit) fit into it easily. I I could probably fit my Coopers FV (which is about 33L) complete with with krausen collar. In fact I think you can get a 60L FV in there.

Onto the main thing does it do what it says on the tin? The Cool brewing site says:


  • One frozen 1-liter bottle will result in a 2.5 degree F drop below room temperature.
  • One frozen 2-liter bottle will result in a 5 degree F drop below room temperature.
  • This method is scalable all the way up to around a 30 degree F drop below room temperature!
The ambient temp in my brewing corner is 22C-23C (even though it's the middle of December!) so having bought some liquid yeast for the first time too - which is why I wanted the fermentation bag in the first place - I planned to aim for 20C. So I reckoned 1x2L ice bottle should do the job.


After pitching the yeast I put the 2L ice bottle in the bag with the FV. The following morning I checked and the temp had duly reached to about 20C. I swapped ice bottles out every 12 hours or so and the bag did indeed maintain a steady temp of about 20C. It been doing that now for four days.

There is a small fluctuation of about 0.5C The lowest it has got is 19.5C (fluctuating from 20C) and the highest is about 20.5C (again fluctuating from 20C), so an overall variation of 1C. Not as good an electronically contolled brewfridge or fermentaion chamber but I can definatley live with that - pretty good for such a low tech solution

I've yet to test the limits of how long you can leave it, the longest I've left it so far is 14 hours with no problems. The cool brewing website says, "A frozen 2-liter bottle typically does not thaw completely in 24 hours so it is easy to maintain a constant temperature drop." After 12-14 hours the 2L bottle has only thawed about 1/2 so I can well believe you could leave it for 24hrs without problem.

The bag itself is made out of some sort of man made material like nylon and feels very sturdy and the inner lining is made out of a vynl material again it feels sturdy. The lining is also obviously water proof as the frozen water bottle 'sweats' and leaves pools of water in the bottlom of the bag but the water hasn't leaked out of the bag and onto the kitchen work surface. If the bottles sweating bothers you the bag is certainly big enough to put a large tray or trug in the bottom and put the FV and water bottles in that to collect the water
Some of the reviews on Amazon complained of the zip breaking and the lining ripping but I understand there is a second version of the bag and I'm pretty sure that is the one I have as everything feels pretty robust.

Now the negatives:

The one big downside is cost. For me to import it into the UK the costs were hideous. For the bag itself plus shipping cost (which was roughly half the cost of the bag :shock:) it was ��£88.86. I then had an import tax charge on top of that of approx ��£21. So it cost me in total about ��£110. If there was a UK distributor I think the bag would probably cost about ��£40

So is it worth it. I think yes. I continually read, consistant fermentaion temps are one of the best things you can do for your brew and as far as function goes this definatley does what it advertises it can do. Without the bag I am unable to use liquid yeast as my brew corner even in the middle of winter is warmer than recommended fermentation temps and this doesn't take into account the added extra temp from the exothermic reaction created during fermentation.

The real test will come during summer but I think the bag will be able to handle it. Cool Brewing claims the bag is able to lower the temp up to 16C lower than ambient with enough ice bottles. T hat being so I think you would even be able to lager using it and I might even have a go.

So overall I give it 4 out of 5. One star less because it's so expensive to import



Being a luddite I don't have a smart phone or digital camera so I've posted some photo's from the web

index.jpg


cool brew bag MAIN1.jpg
 
Last edited by a moderator:
This is exactly the same prinicple of something i designed last year, only I used a plastic dustbin from B and Q (£8.99 i think). I also bought 20 ice packs from the Poundland.
1, Find somewhere in your freezer to keep 20 ice packs (you will get away with 16)....3 for 99p
2, Place fermenting vessel inside dustbin.
3, wedge 8 icepacks in the gap and fill with water.
4, check temp and change ice packs when needed.
5, bit of time faffing about, but what do you expect for less than £20.00
 
This is exactly the same prinicple of something i designed last year, only I used a plastic dustbin from B and Q (�£8.99 i think). I also bought 20 ice packs from the Poundland.
1, Find somewhere in your freezer to keep 20 ice packs (you will get away with 16)....3 for 99p
2, Place fermenting vessel inside dustbin.
3, wedge 8 icepacks in the gap and fill with water.
4, check temp and change ice packs when needed.
5, bit of time faffing about, but what do you expect for less than �£20.00

I tried something similar over the summer with my FV in a water bath and 500ml ice bottles. As you say it's a right 'ol faff. I could only maintain the target temp for 4-6 hours. I also had large temp swings which definately isn't good - I actually think its probably better to have a constant temp at a warmer than desired temp then large temps fluctuations.
 
Good review and has got me thinking. I might try constructing a belt to fit round the chronicle ..insulation on the outside with pockets to take frozen ice packs...like a suicide vest but without bombs. the brewmaster bucket would fit in that bag no probes.
 
Good review and has got me thinking. I might try constructing a belt to fit round the chronicle ..insulation on the outside with pockets to take frozen ice packs...like a suicide vest but without bombs. the brewmaster bucket would fit in that bag no probes.

That's why I was asking you about the demensions of the Chronical the other day, as I have and eye for going SS in the FV dept. next year so will be buying the brewmaster bucket
 
If it enables you to extend your brewing year then it's worth every penny in my book. :thumb:


Sometimes things we buy feel extortionate, but if they work out well and serve us well the cost becomes irrelevant.
 
If it enables you to extend your brewing year then it's worth every penny in my book. :thumb:


Sometimes things we buy feel extortionate, but if they work out well and serve us well the cost becomes irrelevant.

I do brew year round but during the summer I'm exremely limited to what yeast I can use and as I say in my OP I've never been able to use liquid yeast as my brewing corner is too warm. So for that alone I think it's worth it
 
Nice review MQ, I'm space challenged as well and whilst I can warm the FV I don't even try to cool it and stick to the hot weather yeasts in the summer but I'm limited to just the two I can use. I'm looking forward to hear how the bag performs in the summer. I'm presuming that to warm the FV you use hot water do they say to use boiling water or hot water from the tap?
 
Nice review MQ, I'm space challenged as well and whilst I can warm the FV I don't even try to cool it and stick to the hot weather yeasts in the summer but I'm limited to just the two I can use. I'm looking forward to hear how the bag performs in the summer. I'm presuming that to warm the FV you use hot water do they say to use boiling water or hot water from the tap?

I think the bag is only really designed for cooling. There's no mention of using the bag to warm an FV on the site
 
Good review. I was thinking there must be something like this on the market. Still waiting for the temp to drop so I can brew my pilsner.
 
I think the bag is only really designed for cooling. There's no mention of using the bag to warm an FV on the site

hot water bottles would work just the same but to heat if needed..

a diy version should be easy to make from a few cheap ground mats, just make sure the seams are air tight otherwise all the cold air will fall out:whistle:
 
Thanks for that review! Very interesting. Personally, I would only be interested in something so I could use lager yeast as I can keep temps quite stable in the house around 20°. However, I wouldn't even have the space for freezing the ice bottles or the dog will need to go hungry lol!

surely there must be a way people could fashion one themselves - i don't think the material cost could be high when you get soft cool boxes as free gifts sometimes (well those were the times anyway). *thinkingcapon*'
 
I've had the bag a few months now. There's a couple of tips I would add to my original review:

1. Have about twice as much 2L ice bottles in your freezer than you need so you can swap out the melted ones.

2. You can leave the bottles for 24 hours before needing to swap them if you want. Although I usually swap mine, once first thing in the morning and once last thing at night. The bottles are only half melted by then but I prefer to do it that way. However when you first put your FV in the bag and put the first bottles in. Swap them after 4-6 hours. This is because it takes more energy to get your temp down to target than to maintain the temp once it's reached it.

So far I haven't discoved any drawbacks to the brewbag. I've fermented down to 15C to do a pseudo lager from about 18C/19C but I think I could go all the way down to 12C to do a proper lager if I wanted to, given enough ice bottles
 
I want automatic control, don't mind the idea of having to replace ice packs every two or three days, but don't want to have to monitor daily. I want to be able to live 6 miles away and return every few days to collect mail and mow lawn, and if required swap a ice pack.

I know my fridge/freezer does the job fine, but it will not last for ever so keeping an open mind to replacements so I know where I am going when it does finally fail. When hunting due to this thread I noted a kit
Cooling-Cooling-system-DIY-Pro-refrigeration-system-kit-heatsink-Peltier-cooler-TEC1-12706.jpg
it seems they have a pump and a peltier unit and it can pump cool water to where you require cooling. Now that idea looks promising. I realise with the old Hotpoint fridge/freezer I am using it was already piped up. There was a cold water unit built into the door which was connected to the mains water, I would not have taken too much to have adapted this system to have cooled a fermentor alongside the unit. The plus with cold water and a pump is you can use thermostatic control for the pump and cooling device so you can set up and walk away. Be it ice packs, a fridge, or a peltier device, the use of a pump means automatic control.

However as to room, still can't see how using another insulated container and some Heath Robinson set up really saves room? All it does is make it more flexible where the room is taken up.
 
Now the warmer weather is here, just to update the thread a bit. Get er brewed sells the bags (remember the 5% forum discount too :thumb:)

http://www.geterbrewed.com/cool-brewing-bag/?sl=en

I tried the bag with just a 5L FV in their recently and even though the bag absolutely swapped the FV I found it even more effective and only had to use half the usual amount of ice
 
Hi MQ, I'm considering one of these. What's the lowest temp you've ever got to? Also I'm guessing to properly lager something you'd basically need an empty freezer for all the bottles of ice? Might be a touch inconvenient. :-)
 
What's the lowest temp you've ever got to? Also I'm guessing to properly lager something you'd basically need an empty freezer for all the bottles of ice? Might be a touch inconvenient. :-)

Personally I've got it to about 8-10 degrees C. it took alot of frozen water bottles probably about 10l worth and some frozen ice cream tubs (filled with water - not ice cream!) I tend not worry about cold crashing. During fermentation I just have a couple of 2-2.5l water bottles on rotation that keeps temps stable.
 
I got mine down to 10ºc the other week when it was super hot by chucking several ice bottles in.. I am not a big one for crashing either.. tbh the yeast was super flocculant so I kinda wish I hadn't now as I really didn't need to.

Once fermentation is going I can keep it at 18ºc with 1 or 2 x 2L ic bottles.. just rotate morning and night.
 
I want automatic control, don't mind the idea of having to replace ice packs every two or three days, but don't want to have to monitor daily. I want to be able to live 6 miles away and return every few days to collect mail and mow lawn, and if required swap a ice pack.

I know my fridge/freezer does the job fine, but it will not last for ever so keeping an open mind to replacements so I know where I am going when it does finally fail. When hunting due to this thread I noted a kit
Cooling-Cooling-system-DIY-Pro-refrigeration-system-kit-heatsink-Peltier-cooler-TEC1-12706.jpg
it seems they have a pump and a peltier unit and it can pump cool water to where you require cooling. Now that idea looks promising. I realise with the old Hotpoint fridge/freezer I am using it was already piped up. There was a cold water unit built into the door which was connected to the mains water, I would not have taken too much to have adapted this system to have cooled a fermentor alongside the unit. The plus with cold water and a pump is you can use thermostatic control for the pump and cooling device so you can set up and walk away. Be it ice packs, a fridge, or a peltier device, the use of a pump means automatic control.

However as to room, still can't see how using another insulated container and some Heath Robinson set up really saves room? All it does is make it more flexible where the room is taken up.

When the fridge freezer packs up just get another one second hand for £20.
Simples :)
 
Back
Top