Sulphur smells with Saflager S23

[Imperial1]

I brewed a Simple Lager about 3 months ago using Saflager W34/70. Everything went to plan (fermentation temp was about 15C) but the smells through the airlock had a distinct Sulphur smell. After fermentation I racked to a secondary and chiled at 5 degrees for 35 days before bottling. Although the beer tastes OK, there is still a subtle sulphur smell when poured. I assumed I did something wrong?

So last week I did a 35l Bock which I split equally into 2 fermenters because it couldn't all fit in 1. In 1 fermenter I pitched Saflager W34/70 again and in the other I pitched M84 Craft Series Bohemian Lager yeast (with the intention of mixing the 2 when racking into my secondary). 8 days later and fermentation has almost finished but the W34/70 again has the sulphur smell whilst the M84 doesn't (it smells brilliant). Both fermenters had exactly the same wort, same fermentation temperature (this time 11 degrees C) and were otherwise identical in all aspects.

Can any body tell me why the W34/70 has that sulphur smell and what I can do about it as it really does detract from the finished product.

 

[giraffe]

34/70 is prone to throwing sulfur when stressed. Make sure you are piching enough yeast, nutrient, and fermenting near the lower end of the range. Long lagering times will clear up sulfur, but thats usually in a secondary where it can off gas. If you kegged, you could scrub the beer by repeatedly running co2 through the beer post, and then releasing the pressure, in bottles that is problematic.

You can also try adding a piece of copper to the brew kettle, or using a copper wort chiller.

 

[Imperial1]

Thanks for the feedback. I am fermenting at 11 C and pitched 1 packet (11g) of 34/70 in 17l of Wort. The wort was well aerated and I did add yeast nutrient during the boil. I did use a copper coil wort chiller and had excellent hot and cold breaks.Maybe because I pitched the dry yeast directly into the fermenter instead of making a starter was the problem. My OG was also 1.080 so maybe I didn't pitch enough yeast? Once I reach my FG I will rack to a secondary - what can I do to get it to gas off as much as possible as I bottle rather than Keg? I can Lager anywhere between 2C and 7C - which would be best to get rid of the Sulphur smell? I'm interested that the M84 doesn't produce any sulphur smells in the identical environment to the 34/70? Thanks again.

 

[giraffe]

Thats a severe underpitch, thats likely the problem. Lager pitches need to be twice what you pitch in an ale. Id guess 3 packs _rehydrated in water_. Look at mrmalty.com there is a pitching calculator there which hasnt failed me.

Some strains are more prone to sulfur, some are more prone to diacetyl, some are more prone to under attenuating. Im not familiar with the m84 strain in particular, but some are less fussy to work with.

At this point let it sit in the secondary for lagering around 3-4C for 2-3 months. It will likely clear.

 

[pdxal]

Massive underpitch of yeast will cause stress and off flavors. Some varieties of yeast definitely throw a lot of sulfur before cleaning it up as you have found out.
I didn't see mentioned if you did a diacetyl rest. Did you do one? That will help clean up the beer as well.

 

[Imperial1]

Once the gravity had dropped from 1.080 to 1.035 I moved the fermenters from 11C to 18C for 3 days, and racked to my secondary yesterday - gravity down to 1.016. I have moved into a cold room at 4C where I will leave it to lager. It still smells pretty nasty but hopefully will improve as it lagers. The other half of the batch that was fermented with M84 smells and tastes brilliant so I will just have to wait a couple of months before I make a final decision if I can still blend the 2 batches (that was my original plan) or if I should play it safe and at least have half the batch end up drinkable. Interestingly, even though the 34/70 batch still has a sulphur smell it actually tastes pretty good so I remain hopeful. Thanks for the advice.