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Cool Brewing Fermentation Cooler Bag
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Control your fermentation temperatures with Cool Brewing's simple, yet innovative, insulated fermentation bag. This is the 2nd generation Cool Brew bag, which has made cold fermentations even easier!  Fermenting your homebrew at the right temperature is one of the critical factors in making good beer. Let the temperature get too warm, and your beer will taste 'rough' as the soft malt and vibrant hop flavors dissapear!  Typically an advanced homebrewer would want to get a spare refrigerator or even a MoreBeer! Cooled Conical to control fermentation temperatures, both those options either take up a lot of space or can cost a fair amount of money.  The Cool Brewing Bag allows the apartment brewer, those who have space constraints, or the brewer on a budget a great option to control fermentation temperature and make great beer.

Cool Brewing's Fermentation Cooler is designed specifically to accommodate standard 6.5, 6 or 5 gallon fermenter. You freeze a 2 liter soda bottle with water, or similar, and place in the fermentation bag with your fermenting carboy.  Also works great with the Ss BrewTech Brew Buckets!

The typical desired ale fermentation range is on average around 62-72° F.  For a typical 5 gallon batch (1) frozen 2-liter bottle should lower wort temperature around 5 degrees, while using (2) 2-liter bottles will lower wort temperature around 11 degrees for 24-36 hours. Of course your exact results might vary but you can adjust the amount of ice you use as you go. The manufacturer has found they can cool the wort temperature up to around a 30-35° drop from ambient room temperature.  On the flipside, add a Fermwrap and temperature controller to the setup, and you've got a heated fermentation temperature accurate to within 1° F!

The Cool Brewing Fermentation Cooler is sealed, insulated and 100% waterproof so it will efficiently and neatly keep your temperatures in check.  When you’re done, the Cool Brewing Fermentation Cooler easily folds up for storage until the next brew day!

 Cool Brew Features:

  • Up to twice as efficient and cleaner then homemade swamp coolers
  • Much less expensive than custom kegorator or keezer set up's that cost $100's of dollars.
  • Cool Brewing Cooler will work with multiple sized fermenters.
  • 100% waterproof so will not leave condensation.
  • It folds up for easy storage when not in use or travel.
  • Will work great in condos and warm climates where you need a swamp cooler even for Ale’s!
  • Contains the mess of any fermentation blowouts
  • Inner dimensions: 20.5"D x 25.5"H
Item # FE530
Shipping Eligible for Free Shipping Program
Availability California - In Stock
Pennsylvania - In Stock
Weight 5LBS
Community Q&A

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Why did you choose this?
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It was highly recommended by a home brewer.
carlos t on Feb 19, 2018
It was highly recommended by a home brewer.
carlos t on Feb 19, 2018
california weather
Jeff I on Jan 22, 2018
california weather
Jeff I on Jan 22, 2018

4.5 / 5.0
35 Reviews
5 Stars
4 Stars
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1 Stars
Great bag.
It works. Helps avoid volcanoes and keeps temp where it should be.
February 8, 2018
2 months ago
Great Insulation
Works as it should! Lowers my ambient temps by 10-15 degrees. I even uses it in addition to a recirculating cooling jacket to keep a keg cold and force carb before I had my keezer built. Its water proof too!
January 23, 2018
2 months ago
I have been using this ferm bag for 2.5 years after using a tote with iced bottles to control temp. Initially, I filled the ferm bag with water and added iced bottles. That caused rapid cooling and some buffering of temp changes. It also cause condensation on the outside that was not desirable when sitting on carpet. Over time, I have stopped the use of water, but I found it less efficient due to an air gap between the iced bottles and carboy.

Currently, I add bubble wrap around the inside wall of the ferm bag and between carboy and bag's top. This keeps bottles tight against carboy and significantly increases efficiency.

I sit the bag on a few wood slats to avoid condescension issues. I also cold crash using the bag. With the addition of a bedspread on the outside, I can reach 36 degrees. It is a good product to start with and can be improved using additional insulation.
October 20, 2017
Perfect when using with Speidel Plastic Fermenter - 30L (7.9 gal)
So yea, works great here in Sacramento during the summer, swapping out frozen 2L bottles. Just like everyone else who loves this.

What I really like is that it is perfect with the Speidel Plastic Fermenter - 30L (7.9 gal). The height of the Speidel airlock is about the same height as the zipper on the Cool Brewing bag. The top of the airlock is actually a cap actually "floats" on top. When I zip the Cool Brewing bag shut, it pushes the air lock cap down a bit, making it harder for the gas to release.

This produces a louder pop/gurgle when the pressure equalizes and the gas eventually escapes. I find this beneficial, especially when fermentation slows. I know it's still going instead of trying to determine if it's just slow, or has stopped all together.

Before using the bag, gas still being produced would just seep slower, and silently without the force of the zipped bag pressing the airlock cap down. Using the bag, two weeks into fermentation, periodically I can still hear a "pop" (longer between intervals, naturally) telling me it's still going.
September 16, 2016
Was skeptical. Dual use giant cooler.
I use ferment buckets (FE361 -- tap the lids down with a mallet btw) for 4 week ale primary and there is plenty of room for ice around the sides and the top -- the insulated bag is huge. I could probably pack 20+ liters of ice around my buckets if needed. About 1 L of ice per -1F. I use an Oneida candy thermometer to help keep my temperature in range.

April 23, 2016
Lagered in So Cal
I do keep mine inside of a 55 gal drum for added insulation. I've packed with with frozen 1 liter bottles to cold crash down to 38ish. In early Sept., in So Cal, I lagered a dunkel with no problem. Kept it at 36 for 3 months. Just swap out frozed water bottles. Easy.

Cleaning is as simple as turning it inside out and taking a hose to it.

I ferment outside and temps, inside the bag, swing +/- 4 degrees when outside day to night temps swing +/- 20 degrees.
April 9, 2016
Good Product but has short commings
Good product but .... too floppy the bag will knock the airlock out of the carboy hood, little too short - can't accommodate some air locks with 6.5 gal carboy, wish it had more insulation.

March 14, 2016
Works great for me!!
Pretty much what everyone else says about this is true, except the bad stuff. I've had no problems with liner tearing or leaking. I just brewed my first beer using this and when I transferred to secondary fermentor for clearing I took a little sampling. The beer had a very clean taste which makes me wish I would had one sooner. Living in Vegas it's impossible to have a good fermentation temp without some sort of setup. Room I had my fermentor in was around 72 and using a couple of 2 liter bottles kept my temps 10 degrees colder. Definitely recommend this product.
September 11, 2015
how did I ever get along without this?!
I had been scouring the internet for a method to construct a cost effective method of temperature control that would work in my limited space; then I came across this gem. It works so well, so very very well. I use 2 - 3 one liter bottles of frozen water to maintain temps, depending on the stage of fermentation, but 2 is where I'm usually at. Only changing out the bottles roughly every 24 to 36 hours, again depending on the stage of fermentation. I did a fruit add to a secondary recently and had a small overflow, which was contained without a drop leaking out. If you're on the fence about purchasing, I can not recommend this product enough. It's worth every penny!!!
June 23, 2015
Nice Simple Solution To Controlling Temperature With Constrained Space
I'm fairly new to homebrewing (6 months, 12 batches), but after fermenting an early batch at room temperature during the winter, I quickly learned how important temperature control is to the flavor/quality of your brew... Don't get me wrong, the beer was good after it aged out and some of the harshness subsided, but I knew that it wasn't something I wanted to worry about again. As such, this was one of my early "expansion" purchases, and I'm really glad I gave it a shot.

I own a house, but with several pets and an almost-kindergartner running around, there isn't a lot of space for me to set up a fermentation chamber. Honestly, I'm lucky that my wife lets me have my "man cave" downstairs with a beer fridge and a converted fridge for my keg system. Trying to add a chest freezer or another fridge for the sole purpose of temp control just ain't happening (nevermind that I'm on a budget). And, since I live in Western NY, the temperature fluctuates like crazy no matter what season it is.

The Cool Brewing Bag is a simple idea, and it works nicely. The bag is large enough that I've been able to fit both 6-gallon and 5-gallon plastic carboys in it at the same time (it's tight, and not much room to move them, but it works), and I still had room to fit a couple two liters of frozen water. The insulation isn't thick, but the heavy canvas keeps the light out, and it keeps the cold in enough that the bottles last a day or so before having to be changed. Using it, I've been able to keep my brews at pretty much whatever temp that I like, and with the AC on the last month or so, I haven't even needed the bottles; the cooler alone drops the temp a couple degrees, so my most recent batches are chugging along at 66-68 (room temp is about 68-70 (perfect my my Pale Ale and IPA). In fact, I liked it enough that I bought a second one one day when it was on sale.

Bottom line: Don't expect miracles, but if you tend to your beer every day (I often visit just to peek at it anyway), this is a great way to get into the temp control game. Hell, I think this winter I'm even going to try lagering in one... Maybe some day, I'll build a chamber, but for now, this was $60 well spent (again, it was on sale).
June 8, 2015