How Do I Know Whether Reused Yeast is Infected? - Home Brew Forums
Register Now For Free!

Home Brew Forums > Home Brewing Beer > Fermentation & Yeast > How Do I Know Whether Reused Yeast is Infected?

Reply
 
Thread Tools
Old 06-20-2011, 03:36 PM   #1
hiphops
Recipes 
 
Jun 2010
New York City, New York
Posts: 296
Liked 5 Times on 5 Posts



I am going to attempt my first brew with reused yeast: Wyeast 1056. I used it in a pale ale and want to brew an IPA with it. The yeast has been in the fridge in a sealed container for about 2-3 weeks now.

My brewing plan is to pitch that yeast into starter at least 24 hours before brewing and then brew up my new IPA.

Maybe I'm just being a worrywort but how will I know whether this yeast is infected? I'd hate to pitch infected yeast and not know about it until a few months later after eventually drinking my new brew. Are there any telltale signs (i.e., smell, lack of activity in the starter, etc.) I should look out for before pitching it into the new beer?

Thanks all.
__________________
Swim - bike - run - repeat
Indict - convict - affirm on appeal - repeat
Brew - bottle - drink - repeat

 
Reply With Quote
Old 06-20-2011, 04:47 PM   #2
MalFet
/bɪər nɜrd/
HBT_LIFETIMESUPPORTER.png
 
MalFet's Avatar
Recipes 
 
May 2010
NYC / Kathmandu
Posts: 8,632
Liked 1474 Times on 975 Posts


Your best bet would be to taste the spent starter. If it tastes infected, then your yeast sample is the likeliest source. If it tastes normal, it's unlikely that you'll have any infection in your beer.

 
Reply With Quote
Old 06-20-2011, 06:25 PM   #3
ThePearsonFam
Recipes 
 
Feb 2009
Scarborough, Maine
Posts: 884
Liked 14 Times on 11 Posts


Actually, the spent starter will prolly taste bad regardless due to O2. I'd pour the yeast into the starter and then take a small taste of the actual yeast from the container you poured FROM. The yeast should smell and taste good.

 
Reply With Quote
Old 06-20-2011, 07:49 PM   #4
MalFet
/bɪər nɜrd/
HBT_LIFETIMESUPPORTER.png
 
MalFet's Avatar
Recipes 
 
May 2010
NYC / Kathmandu
Posts: 8,632
Liked 1474 Times on 975 Posts


Quote:
Originally Posted by ThePearsonFam View Post
Actually, the spent starter will prolly taste bad regardless due to O2. I'd pour the yeast into the starter and then take a small taste of the actual yeast from the container you poured FROM. The yeast should smell and taste good.
There's a world of difference between oxidized beer and infected beer, and that difference should be readily apparent.

Tasting the contents of the storage container will detect contaminants if they had already wrecked havoc on the sample, but there's no way a taste-test will pick up on a small infectious colony living in a larger population of dormant yeast. As soon as that small infection gets pitched, however, it may quickly out compete the yeast.

 
Reply With Quote
Old 06-20-2011, 07:59 PM   #5
ReverseApacheMaster
Registered User
Recipes 
 
Jul 2009
Keller, Texas
Posts: 4,882
Liked 254 Times on 196 Posts


if it formed a pellicle or firm-filmy bubbles, it's infected

 
Reply With Quote
Old 06-20-2011, 08:02 PM   #6
MalFet
/bɪər nɜrd/
HBT_LIFETIMESUPPORTER.png
 
MalFet's Avatar
Recipes 
 
May 2010
NYC / Kathmandu
Posts: 8,632
Liked 1474 Times on 975 Posts


Quote:
Originally Posted by ReverseApacheMaster View Post
if it formed a pellicle or firm-filmy bubbles, it's infected
Yeah, that would be a hint

...of course, just because there isn't a pellicle doesn't mean that it's not infected.

 
Reply With Quote
Old 06-20-2011, 08:05 PM   #7
jlpred55
Recipes 
 
Aug 2008
Posts: 423
Liked 4 Times on 3 Posts


I reuse yeast all the time, lots longer time frames than that. I make a starter, pitch the yeast, then taste the oxidized (yuck) fermented starter. If it is infected you can smell it! If it is infected you can definately taste it.
__________________
Kegged: Millenium Galaxy IPA, German Pilsner. Apricot Blonde Ale, ACE Witbier, ACE American Wheat.
Bottled: Smoked Red Rye, Old Tanglefoot Barleywine, Tripel, Dubbel, American Farmhouse Ale

 
Reply With Quote
Old 06-21-2011, 10:36 AM   #8
ThePearsonFam
Recipes 
 
Feb 2009
Scarborough, Maine
Posts: 884
Liked 14 Times on 11 Posts


I agree that there's a world of difference between oxidized and infected. I would definitely taste the starter if it were from a vial or pack, but it's reused. If the cake is infected, then you'll most likely smell and taste it by sampling the yeast too. Either way works for reused yeast.

 
Reply With Quote
Old 06-21-2011, 01:02 PM   #9
BelgianKing
Recipes 
 
Jan 2011
Buffalo, NY
Posts: 69
Liked 4 Times on 4 Posts


ive read on here that your starter will have a sour like taste to it and it doesnt taste good either. I have never tasted my starter before but just a heads up.
__________________
Primary:Chicken Livers IPA x10gal
Secondary:
Bottled: Milk Chocolate Stout,Dr. Spock's Bock 001,Dr. Spock's Bock 002

Yeast Bank:1056 3rd Generation

2011 gallons= 61

 
Reply With Quote
Old 06-21-2011, 01:35 PM   #10
ThePearsonFam
Recipes 
 
Feb 2009
Scarborough, Maine
Posts: 884
Liked 14 Times on 11 Posts


Starters don't taste good because of oxidation. The goal is to grow yeast cell counts, not make beer, so we intentionally allow O2 into the process. The result is more yeast and a bad taste...

 
Reply With Quote
Reply
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Reused Yeast & Primary Time Question... BradleyBrew Fermentation & Yeast 4 06-19-2011 02:11 AM
Is there a way to know yeast infected before pitching? Cabbie Fermentation & Yeast 9 06-08-2011 06:04 PM
Saved yeast infected??? mattmuir Fermentation & Yeast 5 06-03-2011 11:08 PM
Reused Yeast on over 150 batches Haputanlas Fermentation & Yeast 40 04-14-2011 08:02 PM
Infected Yeast? baer19d Fermentation & Yeast 2 01-16-2010 05:02 PM


Forum Jump