# Warmer constant temps vs fluctuating cooler temps for fermenting?

**URL:** <https://forum.homebrewersassociation.org/t/warmer-constant-temps-vs-fluctuating-cooler-temps-for-fermenting/17254>\
**Category:** Ingredients\
**Created:** [July 27, 2014, 12:10pm UTC](https://forum.homebrewersassociation.org/t/warmer-constant-temps-vs-fluctuating-cooler-temps-for-fermenting/17254 "2014-07-27T12:10:04Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![ynotbrusum](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/ynotbrusum/32/10316_2.png) [@ynotbrusum](https://forum.homebrewersassociation.org/u/ynotbrusum)\
**Post date:** [July 28, 2014, 6:48pm UTC](https://forum.homebrewersassociation.org/t/warmer-constant-temps-vs-fluctuating-cooler-temps-for-fermenting/17254/21 "2014-07-28T18:48:22Z")

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That’s the deluxe model, Jim, the “Super Cool Brewing Bag”!

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**Author:** ![klickitat\_jim](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/klickitat_jim/32/6601_2.png) [@klickitat\_jim](https://forum.homebrewersassociation.org/u/klickitat_jim)\
**Post date:** [July 29, 2014, 5:47am UTC](https://forum.homebrewersassociation.org/t/warmer-constant-temps-vs-fluctuating-cooler-temps-for-fermenting/17254/22 "2014-07-29T05:47:01Z")

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Righteous

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**Author:** ![beerlord](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/beerlord/32/12231_2.png) [@beerlord](https://forum.homebrewersassociation.org/u/beerlord)\
**Post date:** [July 30, 2014, 3:54pm UTC](https://forum.homebrewersassociation.org/t/warmer-constant-temps-vs-fluctuating-cooler-temps-for-fermenting/17254/23 "2014-07-30T15:54:30Z")

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> [@ynotbrusum](#):
>
> I bought one after seeing it at the NHC, but anything similar would work, too:
> 
> [http://www.cool-brewing.com](http://www.cool-brewing.com)

I have 2 of these now and in my 78 degree house in the summer, 2 quart frozen bottles keep my temps 65-66 by changing them out every 12 hours or so. Last fall, while still warm in my area, I was able to keep temps right at 60 with 4 bottles going after a few days to reach that temperature.  
This week, I put one bag inside the other to see what would happen and my fermenter did fit and 1 quart bottle keeps it at 68 changing every 12 hours.&nbsp;  
For me the trick is to chill my beer (with a pump&nbsp; and ice after using tap water in the chiller) to 65 to get started. Then when fermentation gets going and wants to go above 70, I’ve already had 2 frozen jugs in place to keep things below 70.  
I’ve used them almost 2 years now.

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