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General Category => Yeast and Fermentation => Topic started by: markpotts on May 29, 2015, 02:27:25 PM

Title: Sulphurous / Egg Smell In Starter
Post by: markpotts on May 29, 2015, 02:27:25 PM
Just looking for a few opinions.
I usually use a vial of White Labs or a WYeast smack pack to make a 1 litre starter and then pitch this in to my wort or split it in to 3 parts for storage. I will then use the splits to make more starters when I have a brew on.

This week I used the dregs of a bottle of my HB to make a small 200ml starter (1040 wort made with DME) and it absolutely stinks of sulphur (eggs). The yeast is Wyeast 1469 and the beer has been bottled for around 5 months. The beer tastes as expected.....no off flavours or infection.

I stepped the 200ml up to 1 litre and whilst the smell is still present it is much reduced.

I'm just looking for some reassurance that the starter is okay to use?
I crash cool and on brewday decant off the liquid and then suspend the yeast in a small amount of the wort I've just made before pitching in to the full batch.

I'm assuming that the sulphur is present due to the small quantity of viable yeast left in the beer and therefore stress put upon it during fermentation of the small starter??

Any further thoughts would be appreciated......thanks 8)
Title: Re: Sulphurous / Egg Smell In Starter
Post by: dmtaylor on May 29, 2015, 03:09:00 PM
Sulfur is very very normal for all fermentations.  Don't worry about it at all, as sulfur ALWAYS disappears with just a little aging, ALWAYS.

Cheers!
Title: Re: Sulphurous / Egg Smell In Starter
Post by: Slowbrew on May 29, 2015, 05:49:19 PM
I was going to say, basically, the same as Dave.  No worries.

Paul
Title: Re: Sulphurous / Egg Smell In Starter
Post by: S. cerevisiae on May 29, 2015, 09:53:10 PM
Many yeast strains throw sulfur (sulphur) when stressed.   If you are using a stir plate, reduce the rotational speed.
Title: Re: Sulphurous / Egg Smell In Starter
Post by: HoosierBrew on May 30, 2015, 01:23:41 AM
Sulfur is very very normal for all fermentations.  Don't worry about it at all, as sulfur ALWAYS disappears with just a little aging, ALWAYS.

Cheers!

+1
Title: Re: Sulphurous / Egg Smell In Starter
Post by: erockrph on May 30, 2015, 01:58:05 PM
Sulfur is very very normal for all fermentations.  Don't worry about it at all, as sulfur ALWAYS disappears with just a little aging, ALWAYS.

Cheers!
+1
+2 - Some strains are more likely to throw off sulfur than others. Lager strains and hefe strains are almost guaranteed to do it (at least IME), but any strain CAN throw off sulfur. It's normal and will clear up over time. I prefer to wait for it to dissipate prior to packaging, but it will clear up even in the bottle/keg given enough time.
Title: Re: Sulphurous / Egg Smell In Starter
Post by: S. cerevisiae on May 30, 2015, 03:44:01 PM
The OP stated that his starter was throwing H2S.   H2S production with most lager yeast strains is normal; however, it's a sign of stress with most ale yeast strains.

Mark, try using 50ml of 5% w/v (1.020) wort next time you attempt to start the dregs from a bottle of bottle-conditioned beer.   Five percent wort is less likely to stress the remaining viable cells, and it is easier to diffuse O2 into 5% w/v wort than it is 10% w/v (1.040) wort.  Old cells need to be babied.

Title: Re: Sulphurous / Egg Smell In Starter
Post by: erockrph on May 30, 2015, 06:14:54 PM
The OP stated that his starter was throwing H2S.   H2S production with most lager yeast strains is normal; however, it's a sign of stress with most ale yeast strains.

Mark, try using 50ml of 5% w/v (1.020) wort next time you attempt to start the dregs from a bottle of bottle-conditioned beer.   Five percent wort is less likely to stress the remaining viable cells, and it is easier to diffuse O2 into 5% w/v wort than it is 10% w/v (1.040) wort.  Old cells need to be babied.

Good catch. I didn't notice that he was making a starter from dregs.

I've changed up my dreg procedure a bit recently with good results (partly based on some things I picked up from your posts about storing yeast under beer). I save about 4 ounces of beer with the dregs in the bottle to be cultured, then add it to 4 oz of normal strength starter wort in a mason jar for my first step. This gives you a half-strength starter, with some of the protective effects of the finished beer (i.e., alcohol and pH). Plus by saving some of the liquid beer, you will not only culture up the cells that have flocced out, but also ones that have remained in suspension and could potentially be a bit more active.

Step one takes a while to really get rolling, but I have noticed much healthier and more vigorous ferments when I step up the starter to pitching quantities using this procedure.
Title: Re: Sulphurous / Egg Smell In Starter
Post by: majorvices on May 31, 2015, 12:35:23 PM
Many yeast strains throw sulfur (sulphur) when stressed.   If you are using a stir plate, reduce the rotational speed.

Isn't it also true that sulfur is generated by the yeast in the growth phase? I have never worried about sulfur aromas from a yeast starter. Ever.

I also would say that if it was an ale yeast and there was excessive sulfur in the fermentation I may be concerned, and I have found that there are some times when sulfur was so excessive that it could not be removed, especially in weissbier strains.
Title: Re: Sulphurous / Egg Smell In Starter
Post by: dmtaylor on May 31, 2015, 02:39:18 PM
I've heard that a penny or two in the fermenter or in the glass will knock out excessive sulfur.  Haven't tried it myself.  I did have a batch one time that took several months for the sulfur to disappear.  It was a pilsner.  Once the sulfur was out, MAN, that was a great beer!  It usually goes away in a few days or a couple weeks.  Rarely it takes a lot longer.  But as I said before, in my experience, it ALWAYS goes away with age.  Very  rare to have it take longer than 2-3 weeks, and usually it is just days / a week.
Title: Re: Sulphurous / Egg Smell In Starter
Post by: HoosierBrew on May 31, 2015, 03:04:11 PM
I've heard that a penny or two in the fermenter or in the glass will knock out excessive sulfur.  Haven't tried it myself.  I did have a batch one time that took several months for the sulfur to disappear.  It was a pilsner.  Once the sulfur was out, MAN, that was a great beer!  It usually goes away in a few days or a couple weeks.  Rarely it takes a lot longer.  But as I said before, in my experience, it ALWAYS goes away with age.  Very  rare to have it take longer than 2-3 weeks, and usually it is just days / a week.

Mine always goes away too, Dave. But I've always used a copper IC, in reference to the penny/copper thing. As for ales, the sulfur from wit or weisse strains is usually dissipated after a couple weeks for me. Not long for lager strains either.
Title: Re: Sulphurous / Egg Smell In Starter
Post by: brewinhard on May 31, 2015, 09:38:20 PM
+1 to getting them mostly with hefe strains.  Even with vigorous fermentations there can sometimes be a noticeable amount of sulfur left behind. 
Title: Re: Sulphurous / Egg Smell In Starter
Post by: S. cerevisiae on June 01, 2015, 03:05:56 AM
Isn't it also true that sulfur is generated by the yeast in the growth phase? I have never worried about sulfur aromas from a yeast starter. Ever.

While there are S. cerevisiae strains that throw sulfur, S. cerevisiae yeast strains usually only throw sulfur when stressed.  A particular Burton ale strain throws sulfur, but that's because it is not really an ale strain.   It's a lager strain masquerading as an ale strain.


Title: Re: Sulphurous / Egg Smell In Starter
Post by: markpotts on June 01, 2015, 08:29:29 AM
Thanks for the input guys and the reassurance.
I didn't get a chance to brew this weekend......but the sulphur smell in the step up starter has gone.
Appreciate the shout on the lower gravity starter s.cerevisiae :)
Title: Re: Sulphurous / Egg Smell In Starter
Post by: erockrph on June 01, 2015, 07:23:40 PM
Isn't it also true that sulfur is generated by the yeast in the growth phase? I have never worried about sulfur aromas from a yeast starter. Ever.

While there are S. cerevisiae strains that throw sulfur, S. cerevisiae yeast strains usually only throw sulfur when stressed.  A particular Burton ale strain throws sulfur, but that's because it is not really an ale strain.   It's a lager strain masquerading as an ale strain.
Mark, do you know of any biology behind why weisse/wit strains tend to pump out a lot of sulfur compared to other S. cerevisiae strains? To me, they're worse than many lager strains with the H2S production.
Title: Re: Sulphurous / Egg Smell In Starter
Post by: HoosierBrew on June 01, 2015, 07:30:04 PM
Mark, do you know of any biology behind why weisse/wit strains tend to pump out a lot of sulfur compared to other S. cerevisiae strains? To me, they're worse than many lager strains with the H2S production.

+1.  I've never used a lager strain that's as sulfury as 3944 or 3068. Glad that dissipates quickly.
Title: Re: Sulphurous / Egg Smell In Starter
Post by: S. cerevisiae on June 01, 2015, 08:24:46 PM
Mark, do you know of any biology behind why weisse/wit strains tend to pump out a lot of sulfur compared to other S. cerevisiae strains? To me, they're worse than many lager strains with the H2S production.

The jury is still out on whether or not strains such as W-68 (Wyeast 3068) are truly S. cerevisiae or if they belong to their own Saccharomyces species.  On one hand, W-68 top crops like a domesticated yeast, and shares many genetic markers with S. cerevisiae.  On the other hand, it produces flavors and aroma compounds that are more common with non-S. cerevisiae yeast strains. This weirdness is not without precedence.  If you view the graph on page 1617 of the following publication: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2556262/pdf/1610.pdf, you will see that the Duvel strain that Wyeast sells (GSY161 in the paper) groups with NCYC 361, which is a Saccharomyces diastaticus strain.
Title: Re: Sulphurous / Egg Smell In Starter
Post by: dmtaylor on June 02, 2015, 01:22:33 AM
I am of the belief that German hefeweizen strains and Belgian strains are very very closely related.  Perhaps all are in a new unidentified species, since they are indeed so unique compared to others.