Yeast Starter Acetone Smell

Help Support The HomeBrew Forum:

Brew_DD2

Mint Choc Chipster
Joined
May 20, 2015
Messages
2,210
Reaction score
1,428
Location
Dundee
Hello Folks.

Just took a whiff of a starter I put on the stirplate last night (first step) and there is a distinct aroma of acetone/pear drops. The yeast in question is Imperial L17 and the starter is from a couple of tablespoons from my last batch using this strain (almost a year ago).

So what do we think? Too warm, too old, too oxidised, or too infected?

I am planning to go to the next step of the starter and see if the smell goes.

Worth a try? Or ditch it while I'm ahead?
 

JonBrew

Landlord.
Joined
Jun 5, 2014
Messages
677
Reaction score
354
Location
Perth, Scotland
If you have time to spare I'd personally let it finish out then re-assess. Check the gravity for full attenuation, smell and taste the starter beer. I wouldn't toss the starter at this stage based on smell alone.
 

Northern_Brewer

Landlord.
Joined
Oct 5, 2019
Messages
1,448
Reaction score
1,237
there is a distinct aroma of acetone/pear drops. The yeast in question is Imperial L17 and the starter is from a couple of tablespoons from my last batch using this strain (almost a year ago).

So what do we think? Too warm, too old, too oxidised, or too infected?
Although I don't know that specific yeast, I'd be 80% certain you'll be OK with it. Acetone/pear drops generally points to a stressed or incomplete fermentation, and is usually due to fusel alcohols or ethyl acetate. Fusels generally mean that the yeast is much warmer than it wants to be, ethyl acetate can be due to various things including just not having time to clean up after itself - Beaujolais Nouveau often gets quite pear-droppy as it's rushed from the tanks into bottles in order to hit the release date.

So you'll probably be OK, I'd probably do a second starter with not too-extreme a jump up - or do a same-size starter within the recommended temperature range, starting with maybe 15-20% of your current starter.

But have a backup in case it doesn't get better.
 

the baron

Moderator
Staff member
Moderator
Joined
Oct 13, 2013
Messages
3,764
Reaction score
2,284
Location
castleford
I know grain is not that expensive but hops can be and more so your time the average brew is anywhere between 4 and 6 hours, in my world if it smells of acetone/pear drops that is a inherent well known brewing issue, down the drain for me and no time wasted on a wing and a prayer it will be ok
 

Brew_DD2

Mint Choc Chipster
Joined
May 20, 2015
Messages
2,210
Reaction score
1,428
Location
Dundee
I'll step up the starter. Any whiff of acetone and it's gone. Cheers folks.
 

Brew_DD2

Mint Choc Chipster
Joined
May 20, 2015
Messages
2,210
Reaction score
1,428
Location
Dundee
Well, I left it on overnight and the smell has largely gone. I've stepped up the starter, so I'll wait and see. Any whiff of pear drops come tomorrow, and I'll be brewing the Wookey Jack clone instead.
 

JonBrew

Landlord.
Joined
Jun 5, 2014
Messages
677
Reaction score
354
Location
Perth, Scotland
Well, I left it on overnight and the smell has largely gone. I've stepped up the starter, so I'll wait and see. Any whiff of pear drops come tomorrow, and I'll be brewing the Wookey Jack clone instead.
What are you planning on using the L17 in?
 

Brew_DD2

Mint Choc Chipster
Joined
May 20, 2015
Messages
2,210
Reaction score
1,428
Location
Dundee
My house German Pils. Cashmere/Hallertau Blanc German Pils. Absolutely fantastic. Even if I do say so myself.
 
Top