Kegconnection Complete Starter Kit and More Giveaway!


Home Brew Forums > Home Brewing Beer > Fermentation & Yeast > Fermentation vs. Clean-up

Reply
 
LinkBack Thread Tools
Old 08-06-2009, 12:28 AM   #1
MBM30075
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2009
Location: Roswell, GA
Posts: 221
Default Fermentation vs. Clean-up

I've been tracking some various ideas on this website and have a couple of questions.

About a week ago, I did an American IPA kit. I replaced the Danstar Nottingham yeast in the kit with a SafAle US-05 (seemed more in line with the style, plus I've had great results with US-05). Fermentation went wild for several days then slowed down appreciably.

Now, the batch is still in primary and the blow off solution is still in place. Every couple of minutes I still get some bubbles.

My question is this: Is this still active fermentation or is it a by-product of the yeast cleaning up after itself?

Don't worry, I'm not in a hurry to rack it off; I'm just curious. I have an English Bitter in clearing right now, and it's not going anywhere until I have a keg free, then I'll rack the IPA into that carboy.

Anyway, I'm just curious, what exactly do people mean by the yeast "cleaning up after itself?" I think I've read that it produces a cleaner, clearer, better-tasting beer, but why? Is it taking proteins out of solution? Something else?

Thanks to anyone who can shed some light on this .

__________________
MBM30075 is offline
 
Reply With Quote Quick reply to this message
Old 08-06-2009, 12:49 AM   #2
menschmaschine
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2007
Location: Delaware
Posts: 3,278
Liked 31 Times on 26 Posts

Default

When the yeast run out of sugar to eat, they begin to metabolize ("eat") compounds they produced earlier in fermentation. This includes sulfur compounds, they turn fusel alcohols into esters, etc. After they finish with this, they go dormant. This is what is meant by "cleaning up".

As for your bubbles every few minutes... you really need to check the gravity. If the FG is about where you expected it to be, it's done... to really check this, you could check it a couple days from now and if it's still the same gravity, then you know it's done. Recently fermented beer also tends to have CO2 coming out of solution. So, if your beer is finished, that would explain your airlock bubbles.

__________________

END TRANSMISSION

menschmaschine is offline
 
Reply With Quote Quick reply to this message
Old 08-06-2009, 12:51 AM   #3
david_42
Feedback Score: 0 reviews
 
david_42's Avatar
Recipes 
 
Join Date: Oct 2005
Location: Willamina & Oak Grove, Oregon, USA
Posts: 25,651
Liked 133 Times on 126 Posts

Default

Slow bubbles can also be due to a low-pressure weather system moving in.

__________________

Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"

"I would like to die on Mars, just not on impact." Elon Musk

david_42 is offline
 
Reply With Quote Quick reply to this message
Old 08-06-2009, 12:59 AM   #4
MBM30075
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2009
Location: Roswell, GA
Posts: 221
Default

I'll check the gravity when I rack to secondary. It'll be another week at least, so the yeast will have plenty of time to finish eating all of the sugar they want. I've never had a problem with US-05 attenuating properly, and since this batch has acted normally the whole way around, I'm not worried about it.

I'm assuming that allowing the yeast to keep working until they go dormant themselves is a good thing? That is, I want them to eat the compounds they produced, right? How long would it be until I have to worry about autolysis, if at all?

Thanks!

__________________
MBM30075 is offline
 
Reply With Quote Quick reply to this message
Old 08-06-2009, 02:00 AM   #5
menschmaschine
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2007
Location: Delaware
Posts: 3,278
Liked 31 Times on 26 Posts

Default

Quote:
Originally Posted by MBM30075 View Post
How long would it be until I have to worry about autolysis, if at all?
Under typical circumstances, it's a long wait for autolysis. However, depending on the temperature at which the beer is stored and depending on the beer style, decaying yeast cells and primary trub can cause off-flavors. This is more noticeable in cleaner beers (e.g., light lagers). The typical ale can sit on the primary yeast for 3 to 5 weeks w/o much problem though.
__________________

END TRANSMISSION

menschmaschine is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
The top came clean off Hugh_Jass Beginners Beer Brewing Forum 13 04-19-2009 02:47 AM
Oxi Clean Ernie3 Beginners Beer Brewing Forum 14 11-14-2008 09:10 PM
Clean Clean Yeast uwmgdman Recipes/Ingredients 6 04-06-2007 04:46 AM