Cold Crashing

ccm · June 28, 2013, 7:22pm

I’ve been having issues with over attenuation and still can’t figure out why…any how, I have a stout fermenting right now that’s at the FG I want, but don’t want it to go lower. I’m going to cold crash it to stop the yeast. It’s been fermenting for about one week.

My question is, will cold crashing at this early stage in fermentation stop the yeast from “cleaning up” after themselves?? I’ll crash it for a day or two, then I’ll have to raise the temp back up to 70ish to make room in the fridge for the next batch.

tom_sawyer · June 28, 2013, 7:37pm

Yes it may very well stop all activity, both good and bad. i’d take a taste of the beer to be sure its OK.

You might try using a lower-attenuating yeast. Something like S-04 or one of several British ale yeasts for example.

dobe12 · June 28, 2013, 7:40pm

Not answering your main question, but addressing the underlying question… yeast strain, grist, and mash temp all contribute to either high or low attenuation. Sounds like you may want to mash a little warmer.

ccm · June 28, 2013, 7:44pm

I’ve been having the over attenuation issues with a lot of different yeasts. Even with this recipe and this yeast, I used to get higher FG’s like 1.018-1.020 which I liked. The last time I brewed it it finished at 1.008. It’s at 1.012 now. This last brew I mashed at 155 and didn’t lose more than a couple degrees. I have double checked my thermometer with a NIST certified one, too.

I’m drinking a sample right now and it tastes about what it should. It’s got a bit of a green taste, but that should go away with time.

shadetree · June 28, 2013, 7:54pm

[quote=“CCM”]I’ve been having the over attenuation issues with a lot of different yeasts.[/quote]Check your thermometer to make sure you’re mashing where you think you are.

ccm · June 28, 2013, 8:00pm

I bought a NIST certified thermometer and checked my digital one I use at a range of temps. It checks out.

dobe12 · June 28, 2013, 8:11pm

Post your recipe with yeast used.

tom_sawyer · June 28, 2013, 8:23pm

Mash a few degrees warmer then. regardless of what your thermometer reads, the mash temp is what it is and if you are making a more-fermentable wort then mash warmer. Also mash out and get the wort boiling ASAP. I would limit the time of the mash somewhat as well.

taffin · June 30, 2013, 4:49am

While I haven’t personally tried it, cold crashing and then getting the beer off the yeast before you raise the temp back up should work. Pilsener Urquell halts their fermentation early at about 1.015 (if i remember correctly) to get the profile they want, and I would say it works for them.