Whodini krausen! Disappeared, then re-appeared!

[Brew-Dog]

*Posted this earlier today and only got one response, so I'm posting it here in the fermentation and yeast section. Hoping to get a little insight. Mods, feel free to delete this thread if it's not allowed to be in more than one place.


Anybody have any experience with getting two different krausens from the same batch? I’m still pretty new to brewing, but this seems a little odd to me.

On Friday, I decided to brew a half batch (2.5 Gallons) of Graff (it’s a cider with malt and hops). I followed the recipe (https://www.homebrewtalk.com/f81/graff-malty-slightly-hopped-cider-117117/) pretty closely, and used US-05 yeast.

OG was 1.06. It was my first time using dry yeast and I pitched the whole packet. It said to sprinkle the yeast into the fermenter. Since I was sprinkling it into a carboy, most of the yeast was landing in the same place, so I pitched a little, gently shook the carboy to help spread the yeast, and then pitched a little more and continued the process until all the yeast was pitched. According to my temperature strip, the wort temp was 77f.

Within two and a half hours a small krausen began to form. It looked kind of greenish grey. By that time, the temp was 75f.

Other brewers had said that they got a pretty big krausen with this recipe and the need for a blow off tube, but mine wasn’t that big.



By Sunday, most of the krausen had fallen (except for the small ring around the outside) and the cider was noticeably lighter in color. The temp has remained steady at around 68-70f.

This morning (Tuesday), I took a look at it and to my surprise, a new krausen had formed! This one looked a little thicker and much cleaner/creamier.

I’m not worried, I actually laughed when I saw it. I decided to name this batch Whodini Cider. I’m just curious about what the heck is going on. Is something like this normal? What does it mean?

Was I not suppose to shake the carboy when I added the dry yeast? I didn't rehydrate the packet because I read opinions for and against it, so I figured it would be fine without. Keep in mind I also used a whole packet for a 2.5 gallon batch. According to Mr.Malty, this was the amount I was suppose to use.

 

[daksin]

I'd never had this until last week. Racked a IIPA over to dry hop and now it's back to rocking. Very unusual for me.

 

[winvarin]

Did you change the temp or agitate it in any way? Move it? Rock the carboy, etc?

I am finishing out a lager right now that the yeast has been stubborn in giving up the last few points. In order to keep the yeast active, I bumped the temp up a few degrees and was rocking/swirling the fermenter twice a day.

The yeast woke back up and formed a nice, thick krausen while I was doing that. I also got the beer to terminal gravity.

Your first krausen likely had some break and hop matter in it which gave it the color. Chances are that your second krausen formed after a lot of that other stuff had settled into a more compact layer at the bottom of the fermenter.

 

[Revvy]

Somehow it got agitated or the temp wasn't as steady as you think and fermentation wound down, but then the yeast either warmed up and started again, finding the sugars that were missed the first time. Or the fermenter got jarred and the yeast got kicked up and found the rest of the sugars.

Not exactly strange...especially to folks who rack too early and the agitation of racking over re-woken the yeast.

 

[Brew-Dog]

Did you change the temp or agitate it in any way? Move it? Rock the carboy, etc?

Temperature has stayed the same since Sunday (before the new krausen formed), however, I did have to move the carboy over a couple feet on Sunday when I was doing some bottling. I tried to keep the agitation to a minimum, but it must have kick-started the yeast again. In hindsight, I'm guessing this was a good thing?

I am finishing out a lager right now that the yeast has been stubborn in giving up the last few points. In order to keep the yeast active, I bumped the temp up a few degrees and was rocking/swirling the fermenter twice a day.The yeast woke back up and formed a nice, thick krausen while I was doing that. I also got the beer to terminal gravity.

Congrats! I can imagine it would be a pain in the butt to invest that much time in a lager without getting the desired gravity.

Your first krausen likely had some break and hop matter in it which gave it the color. Chances are that your second krausen formed after a lot of that other stuff had settled into a more compact layer at the bottom of the fermenter.

I was guessing the original colour of the krausen had to do with hop matter. I think I'm chilling my brews quickly enough, but still have to learn more about cold breaks.

 

[Brew-Dog]

Somehow it got agitated or the temp wasn't as steady as you think and fermentation wound down, but then the yeast either warmed up and started again, finding the sugars that were missed the first time. Or the fermenter got jarred and the yeast got kicked up and found the rest of the sugars.

Thanks for the info! For future reference, is it a good idea to agitate the fermenter if you think that your fermentation hasn't been vigorous enough? If I hadn't moved the carboy and unknowingly re-started the yeast, I would have assumed that the fermentation was finished before it had reached its potential. I suppose I probably would have also had a disappointing FG.

 

[cageybee]

when I dry hop, I get what I think is a Psuedo-krausen....just hops all bloated and floating. it's not a product of fermentation activity. I wonder if that's all you saw....followed by a "real" krausen formed by real fermentation activity.

 

[winvarin]

For future reference, is it a good idea to agitate the fermenter if you think that your fermentation hasn't been vigorous enough?

Only your hydrometer can say. I usually try to chill (ales and lagers) to a couple of degrees below my desired fermentation temp. Then I set my fermentation fridge controller to my desired fermentation temp and allow the yeast activity to bring the temperature up.

As fermentation slows, I slowly bring the temp up 2-3f above my fermentation temp (ales) or 7-10f (lagers). This helps the yeast remain active enough to clean up any undesired flavors and aromas and get to FG easier.

But I always take at least one hydro reading before moving to secondary for dry hop or straight into the keg. If I have not hit my anticipated gravity, I will either rouse the yeast or keep it warm (or both).

But let your hydrometer guide you. It is much better at measuring fermentation progress than your eyes are.

 

[Brew-Dog]

I usually try to chill (ales and lagers) to a couple of degrees below my desired fermentation temp. Then I set my fermentation fridge controller to my desired fermentation temp and allow the yeast activity to bring the temperature up.

As fermentation slows, I slowly bring the temp up 2-3f above my fermentation temp (ales) or 7-10f (lagers). This helps the yeast remain active enough to clean up any undesired flavors and aromas and get to FG easier.

But I always take at least one hydro reading before moving to secondary for dry hop or straight into the keg. If I have not hit my anticipated gravity, I will either rouse the yeast or keep it warm (or both).

Thanks for the advice. Next time I'll try to chill the wort a couple degrees below room temp and then pitch. If fermentation is lacking after a few days, I'll move the carboy out of the basement and upstairs where it's a few degrees warmer. Temp is pretty steady in the basement and main floor.

 

[Brew-Dog]

when I dry hop, I get what I think is a Psuedo-krausen....just hops all bloated and floating. it's not a product of fermentation activity. I wonder if that's all you saw....followed by a "real" krausen formed by real fermentation activity.

I think there was definitely some hop particles in there, but probably not too much. It was only a 2.5 gallon batch with 0.25 oz of hops (I know, barely any).