The Great Bottle Opener Giveaway

Home Brew Forums > Home Brewing Beer > Beginners Beer Brewing Forum > what are some causes of under attenuation?

Reply
 
LinkBack Thread Tools
Old 05-10-2010, 03:47 AM   #1
jigidyjim
Feedback Score: 0 reviews
Recipes 
 
Join Date: Mar 2009
Location: Oakland, CA
Posts: 695
Liked 3 Times on 3 Posts

Default what are some causes of under attenuation?

After 15 batches, I have my first batch that missed the yeast's attenuation range (got 62%, range min is 68%). Maybe or maybe not also important, it was all my first all-grain batch, and I didn't get great efficiency (~50%).

At any rate, I'm curious to learn what some causes of under attenuation are, so I can figure out if I did something wrong or not. Are there things under my control that affect attenuation?

The beer tastes great, so I'm happy with it, but due to my efficiency and under attenuation, it's only going to be 3% ABV. I guess that just means I get to drink twice as many each night

__________________
jigidyjim is offline
 
Reply With Quote Quick reply to this message
Old 05-10-2010, 03:52 AM   #2
hfd73
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2009
Location: Houston
Posts: 30
Default

What was your OG and FG? also what temp did you ferment at?

__________________
hfd73 is offline
 
Reply With Quote Quick reply to this message
Old 05-10-2010, 03:54 AM   #3
JonK331
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
JonK331's Avatar
Recipes 
 
Join Date: Nov 2009
Location: Fremont, CA
Posts: 2,100
Liked 28 Times on 28 Posts
Likes Given: 6

Default

1. Underpitching
2. Aeration/oxygenation
3. Temperature
4. Amount of unfermentables

Not necessarily in that order.

__________________
JonK331 is offline
 
Reply With Quote Quick reply to this message
Old 05-10-2010, 03:59 AM   #4
alcibiades
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2009
Location: Stafford, Virginia
Posts: 728
Liked 14 Times on 11 Posts

Default

ive had underattenuation that I know was due to a temp drop at high krausen...

__________________
alcibiades is offline
 
Reply With Quote Quick reply to this message
Old 05-10-2010, 04:01 AM   #5
jigidyjim
Feedback Score: 0 reviews
Recipes 
 
Join Date: Mar 2009
Location: Oakland, CA
Posts: 695
Liked 3 Times on 3 Posts

Default

OG was 1.04, FG was 1.14. I think that makes my attenuation closer to 65% not 62%, but I still have the general question. Fermentation was mid 60's (65-68).

I made a starter of wlp004, before pitching, so given my low OG, I'd be surprised if I under pitched.

Aeration I suppose is a potential point - I don't really do much to aerate, aside from that when I pour in the wort I pour through a strainer, and I shake the carboy up a bit during the process... although for this batch I didn't spend as much time on that step as normal. Hmmm...

What sorts of things control the amount of unfermentables? For example there was 12-16 ounces of espresso in there, would that have an impact in a 5 gallon batch?

__________________
jigidyjim is offline
 
Reply With Quote Quick reply to this message
Old 05-10-2010, 04:53 AM   #6
JonK331
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
JonK331's Avatar
Recipes 
 
Join Date: Nov 2009
Location: Fremont, CA
Posts: 2,100
Liked 28 Times on 28 Posts
Likes Given: 6

Default

Keep in mind that the attenuation listed by the manufacturer is optimal. When I started oxygenating my attenuation went up quite a bit. I've heard that the fish pump with sanitary filter + aeration stone works great as well.

__________________
JonK331 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
attenuation too low? lflesh Beginners Beer Brewing Forum 9 04-15-2009 08:07 AM
attenuation nutcase All Grain & Partial Mash Brewing 4 04-14-2009 09:55 AM
94% attenuation dsdrake219 Cider Forum 5 04-11-2009 01:57 PM
Need....More....Attenuation! FishinDave07 Mead Forum 11 07-24-2008 07:19 PM
92% attenuation! the_bird General Techniques 4 06-29-2007 11:25 AM