Author Topic: Help: Rotten egg flavour  (Read 8943 times)

Offline Manolo

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Help: Rotten egg flavour
« on: December 15, 2007, 11:40:24 AM »
I just brew a stout beer today. I has been a long day of work...

I prepared a yeast starter to get my yeast ready while I'm waiting for the wort to cool down.
I made the preparation with a 200 cl of wort from the mash before the boiling step.

I just had a look to the preparation a moment ago. The yeast is a the botton of the glass, though is a top fermenting yeast. The worst of all, there is an awful and unbearable smell of rotten eggs.

According to some forums on the net, it could be either yeast autolysis, the byproduct of some yeast natural reactions or an infection. I do not really know what to think. Anyway, I've just thrown the preparation down the sink and used some yeast I had left from another beer. I rather not risk a day-long work.

Do you have any ideas about where this rotten egg smell could come from?

Thanks

Manolo

brew_boy

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Re: Help: Rotten egg flavour
« Reply #1 on: December 17, 2007, 12:41:39 PM »
Manolo,
The BJCP Exam Study Guide offers the following:
Sulfury/Yeasty
These flavors, not to be confused with DMS, have the aroma and taste of rotten eggs, shrimp or rubber. The compounds responsible for these flavors originate from sulfur-containing amino acids such as cysteine and methionine. Possible sources include yeast autolysis, bacterial spoilage and water contamination. These flavors can be quite putrid and are not desirable in any style. In the same family are sulfitic flavors, which recall the aroma of a struck match. They are usually due to the overuse of antioxidants, and while rare in beer, are quite common in wine and cider.
Good luck,
Les

Offline Andrewqld

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Re: Help: Rotten egg flavour
« Reply #2 on: December 20, 2007, 03:14:22 PM »
Some lager yeasts will throw a slight sulphury/rotten egg gas aroma as part of their metabolism by products, this aroma is usually cleaned up by the yeast as it continues to work. If you used an Ale yeast then it is more likely an infection and I would ditch the lot.

Cheers
Andrew

Rick

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Re: Help: Rotten egg flavour
« Reply #3 on: December 23, 2007, 09:00:29 AM »
Quote
I prepared a yeast starter to get my yeast ready while I'm waiting for the wort to cool down.

Just a side note: if you made the starter the same day you pitched it, it wasn't a starter.  A starter requires a few days prior to pitching to allow the yeast to get started; i.e., go through some of the initial multiplying phase.

Rick

Offline billpet

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Re: Help: Rotten egg flavour
« Reply #4 on: December 29, 2007, 07:49:30 AM »

I made the preparation with a 200 cl of wort from the mash before the boiling step.


If you are saying that you did not boil the starter wort at all, that could be a problem. When making a starter (or activator on brew day) you need to boil then cool the wort before adding the yeast.

Without boiling, the wort was probably full of wild yeast and maybe some bacteria.

-Bill

Offline Manolo

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Re: Help: Rotten egg flavour
« Reply #5 on: December 30, 2007, 07:14:04 AM »
Thanks all of you for your information. Fortunately, I threw the infected yeast away and used another yeast I had from another beer. The secondary fermentation seems to be all right. I have recently tasted the wort and there is no sign of infection (i.e.: no traces of an acid unpalatable taste) and the gravity decreases at a normal pace.

Based on your information, this is what I'll do next time 48 h prior to my brew: I'll prepare some wort (say 200 cl) with a spoon of extract powder. I'll boil it for about 30 min. and pitch the yeast once it is cold enough. I guess that's a safer way to make an efficient starter.

What do you think ?

Cheers,

Manolo
« Last Edit: December 30, 2007, 09:50:32 AM by Manolo »

malangon

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Re: Help: Rotten egg flavour
« Reply #6 on: January 02, 2008, 10:56:29 AM »
I had this happen to me as well once.  The odor was so sharp it made me jolt away from the package.  Wyeast responded and I spoke with one of their microbiologists about it.  It's fine, you just need to give the yeast a little bit of time to rejuvenate and throw off the odors.
 
I too threw mine away and Wyeast actually sent me a new activator pack even though I was the idiot.  Great company.
 

brew_boy

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Re: Help: Rotten egg flavour
« Reply #7 on: January 02, 2008, 01:22:48 PM »
Manolo,

You might want to use a little more DME in your starter.  Jamil Zainasheff has posted several dicussions about making a proper starter and his recommendation is that you use a 10-to-1 ratio of final water volume to DME, or 10 ml of water for 1 gram of DME.  So in your case, a 200 cl starter would be 2,000 ml total so he suggests 200 grams of DME.  I've used this ratio for about 6 months, preparing my starter about 24 hours before brewing, and have had great success.

Here is the link if you'd like to read more: http://www.mrmalty.com/starter_faq.htm

Good luck,

Les

 

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