*Ss Brewing Technologies Giveaway - Enter Now!*

Home Brew Forums > Home Brewing Beer > Fermentation & Yeast > Acetaldehyde pt II
Reply
 
LinkBack Thread Tools
Old 07-15-2010, 01:39 AM   #1
winvarin
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
winvarin's Avatar
Recipes 
 
Join Date: Apr 2009
Location: Edmond, OK
Posts: 1,089
Liked 49 Times on 45 Posts

Default Acetaldehyde pt II

I posted a thread here a couple of weeks ago. I had a blonde ale that got dinged for acetaldehyde at a recent competition. I was pretty sure that my issue had been a combination of low fermentation temps making the beer ferment slower along with pulling the beer too soon. It was my first temp controlled ale and I used to be on a standard schedule of a 1 week primary, a week in secondary than straight into the keg or bottle.

Works ok mostly, if you're fermenting at room temp. But in a 60-65F fridge, not so much. I am pretty sure I burned myself again.

I had an IPA that had just hit the keg about the same time I got my scoresheets back on the blonde. I had done it with the same schedule. A week on the yeast in the primary, rack to the secondary and into the keg.

About 2 weeks in keg, I tasted it tonight. The hops cover up some of the flavor, but the taste that I finally learned was the green apples of acetaldehyde is there in this beer too. It's not overpowering. It's not horrid. But it is present.

Now I need to figure out how to make sure history doesn't repeat with the saison and porter I have fermenting now.

The saison should be OK. It's 17 days into primary and at about 70ish% attenuation. I am going to pitch a little WLP001 or Safeale 05 this weekend and try to dry it out some more. I figure the extra yeast and another 10 days or so in primary should help combat the acetaldehyde monster.

My porter is an odd duck though. It's 10 days in the primary now with a double-pitch of WLP001. I have been fermenting at right around 65F (the digi thermometer I have in it ranges from 61F-71F throughout the day. It's in a fridge in a hot garage with a controller). But 10 days in, I am still getting a bubble every 3 seconds through my blow off rig. Is that normal for temp controlled ferments? I was planning on 3 weeks in the primary then a week of dry hop in the same primary before kegging.

I have not taken a gravity reading but I still have about 1/2 inch of krausen. Is 001 known to ferment this slow at low temps? SHould I kick it up or just leave it at its current temp and wait it out?

__________________
winvarin is offline
 
Reply With Quote Quick reply to this message
Old 07-15-2010, 02:06 AM   #2
Hypnolobster
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2010
Location: litchfield, oh
Posts: 72
Liked 3 Times on 1 Posts

Default

1 week in primary really isn't quite enough. Let it sit for a week and a half to 3 weeks. When they start to slow down, you can increase the temperature to keep the yeast active.

The porter is likely pretty much finished. I'd increase fermentation temperatures to increase yeast activity to get them to clean up after themselves. Krausen on top after 10 days is a little weird, but it depends on a lot of factors. If you let it sit where it is for another few days it won't be a bad thing, but I would personally increase the temp.

__________________
Hypnolobster is offline
 
Reply With Quote Quick reply to this message
Old 07-15-2010, 08:34 AM   #3
944play
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jul 2008
Location: Santa Rosa, CA
Posts: 2,733
Liked 35 Times on 32 Posts
Likes Given: 56

Default

If you're just leaving the fermenter in a fridge that's set to 65, the beer will be much warmer than that during the most active part of the ferment; then, just as the yeast are getting pooped out and the sugars are almost exhausted, the beer temp drops to your setpoint, putting your beasties into hibernation before they can finish metabolizing acetaldehyde into ethanol.

If you don't have a way to control the beer temp more directly, just set the fridge a couple ticks below the lower bound of the recommended range for whatever strain you're using. Watch for the kraeusen to start to fall, or beer temp to peak, then increase the setpoint a few degrees over the next couple days. Then, as the mind control crustacean says, leave it on the yeast a while, then cold crash and keg!

Had a bottle of Bud the other night....

__________________
OD: ?
Pri:-
Keg: Simple AIPA (2-row, Chinook, Cascade, WLP090)
944play is offline
 
Reply With Quote Quick reply to this message
Old 07-15-2010, 04:09 PM   #4
winvarin
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
winvarin's Avatar
Recipes 
 
Join Date: Apr 2009
Location: Edmond, OK
Posts: 1,089
Liked 49 Times on 45 Posts

Default

Quote:
Originally Posted by 944play View Post
If you're just leaving the fermenter in a fridge that's set to 65, the beer will be much warmer than that during the most active part of the ferment; then, just as the yeast are getting pooped out and the sugars are almost exhausted, the beer temp drops to your setpoint, putting your beasties into hibernation before they can finish metabolizing acetaldehyde into ethanol.

If you don't have a way to control the beer temp more directly, just set the fridge a couple ticks below the lower bound of the recommended range for whatever strain you're using. Watch for the kraeusen to start to fall, or beer temp to peak, then increase the setpoint a few degrees over the next couple days. Then, as the mind control crustacean says, leave it on the yeast a while, then cold crash and keg!

Had a bottle of Bud the other night....
The controller for the fridge my porter is in is set at 70F. The digi thermometer has a "hi"/"lo" functions that records the temp range it hits. The thermometer has registered temps between 71 and 63. Most of the time when I look at it and the fridge is turned off, it's reading 65F-68F.

The krausen had hit as high as the neck of the bottle, but has receded to where it is just the half inch of foam on top. You think I should push the whole thing up to 72-74F on my controller now?
__________________
winvarin is offline
 
Reply With Quote Quick reply to this message
Old 07-15-2010, 04:47 PM   #5
ksbrain
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2007
Location: Mystic, CT
Posts: 1,018
Liked 11 Times on 11 Posts
Likes Given: 2

Default

Where's your temperature probe? I tape mine to the side of a fermenter "insulated" with a folded up paper towel, and it tracks with the stick-on thermometer on the side of the fermenter.

__________________
ksbrain is offline
 
Reply With Quote Quick reply to this message
Old 07-15-2010, 05:18 PM   #6
winvarin
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
winvarin's Avatar
Recipes 
 
Join Date: Apr 2009
Location: Edmond, OK
Posts: 1,089
Liked 49 Times on 45 Posts

Default

Quote:
Originally Posted by ksbrain View Post
Where's your temperature probe? I tape mine to the side of a fermenter "insulated" with a folded up paper towel, and it tracks with the stick-on thermometer on the side of the fermenter.
Mine is rolled up and sitting on a shelf, about 3 or 4 inches above the fermenter
__________________
winvarin is offline
 
Reply With Quote Quick reply to this message
Old 07-15-2010, 05:32 PM   #7
weirdboy
HBT_LIFETIMESUPPORTER.png
Feedback Score: 4 reviews
Recipes 
 
Join Date: May 2009
Location: Los Angeles
Posts: 7,974
Liked 431 Times on 352 Posts
Likes Given: 60

Default

You might consider investing in a temperature controller like the Johnson A419ABC-1C.
Just plug the fridge into the controller, and your controller into the fridge. Crank your fridge up to the max setting at let the Johnson figure out when to turn it on. Min maintains temps quite well and runs the fridge a lot less than if I use the built-in thermostat.


Also you really do want the probe to be stuck to the side of the fermenter if possible, and insulated from the surrounding air. Even better is if you can get a waterproof probe and stick it inside the fermenter...

__________________
weirdboy is offline
 
Reply With Quote Quick reply to this message
Old 07-15-2010, 07:09 PM   #8
winvarin
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
winvarin's Avatar
Recipes 
 
Join Date: Apr 2009
Location: Edmond, OK
Posts: 1,089
Liked 49 Times on 45 Posts

Default

Quote:
Originally Posted by weirdboy View Post
You might consider investing in a temperature controller like the Johnson A419ABC-1C.
Just plug the fridge into the controller, and your controller into the fridge. Crank your fridge up to the max setting at let the Johnson figure out when to turn it on. Min maintains temps quite well and runs the fridge a lot less than if I use the built-in thermostat.


Also you really do want the probe to be stuck to the side of the fermenter if possible, and insulated from the surrounding air. Even better is if you can get a waterproof probe and stick it inside the fermenter...
I am using the Johnson dial controller and currently have it set at 72F
__________________
winvarin is offline
 
Reply With Quote Quick reply to this message
Old 07-15-2010, 07:43 PM   #9
HokieBrewer
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2008
Location: Greensboro, NC
Posts: 1,075
Liked 27 Times on 24 Posts
Likes Given: 25

Default

I have the same issue on a brown ale fermented with US-05, which is very similar to 001. About 12 days in primary, fermentation is basically done, but I still have 1/2 of bubbly krausen mess on top. Weird.

__________________
HokieBrewer is offline
 
Reply With Quote Quick reply to this message
Old 07-15-2010, 07:44 PM   #10
TonySwank
Feedback Score: 0 reviews
Recipes 
 
Join Date: Apr 2009
Location: Houston
Posts: 80
Liked 2 Times on 1 Posts

Default

I've read that the acetaldehyde flavor can disappear with age but does cooling/carbing the keg pretty much keep it in the beer?

Last batch tastes like cut grass, undrinkable. Usually leave 3-4 weeks in the primary but pulled off after 1 week this time. It's a light brown ale (OG 1.042) and already hit the FG so thought it might be ok. Never experienced this before but sounds like acetaldehyde is the culprit.

__________________
TonySwank 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
How to pitch yeast to absorb acetaldehyde? JollyToper Fermentation & Yeast 4 11-17-2010 12:37 PM
Vienna Lager acetaldehyde help... r2eng Fermentation & Yeast 4 04-15-2010 11:52 PM