Slight Sulfur During Primary

Winemaking Talk - Winemaking Forum

Help Support Winemaking Talk - Winemaking Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Countrygent

Member
Joined
Oct 9, 2018
Messages
38
Reaction score
22
Location
British Columbia or Washington State
Just a slight sulfur odor appeared on day 3 primary fermenting my Winexpert Eclipse Stags Leap Merlot. I had made three tweaks from what came in the kit: used RC-212 yeast instead of the supplied EC-1118; put only one half of the supplied oak sawdust in, but put it in a nylon brewers bag with the supplied grape pack, plus about half a gallon of Pinot Noir pomace from a pressing of frozen must I had made last week (and frozen the pomace immediately). I started with supplied bentonite as recommended, although what a clumpy mess, next time I might dissolve it in a blender.

The Pinot Noir pomace had been fermented with Assmanhaussen yeast, co-inoculated with White Labs liquid MLF at Brix 5 as they recommend. I wonder whether I co-inoculated this ferment with either or both of the yeast and/or MLF through the pomace, which had only been in the freezer until it was gelled, not frozen solid.

Starting SG 1.10, the ferment was active pretty quickly, incredibly jammy, fruity smelling on days 1 and 2 after pitching ... but on day 3 at about 1.07 SG a definite sulfur smell, not overpowering but there. I did a few things immediately: 1. Fed Fermaid K in two small feedings about 18 hours apart, at half the recommended rate, the second at SG 1.05; turned down the temperature in the room from 72 to 69 (the ferment looked a little overactive and the bag of grape skins was holding in heat - it was hovering just around the low 80’s), 3. Decided the pomace experiment might not be helping in the bag having so much mass, not gassing the sulfur I could smell in it and also holding down heat and gassing-off, so removed it and pressed, then threw in some oak cubes. 4. Sanitized a small pitcher and gave the fermenting juice a few minutes of dipping and pour back to try and aerate it somewhat.

Now on day 5, still a very slight sulfur smell, slower ferment, SG down to 1.03, temp 76.

I intend to bulk age with oak cubes for a couple of months, will probably skip the sorbate but when the primary stalls out at an appropriate SG below .997 will treat with Kmeta and follow the prescribed fining/clearing/racking recommendation.

Have read as much as a I could find on H2S. Seems to me I have taken the initial steps to try and get a handle on it, now best to wait even though the slight sulfur smell is still there, until I rack to secondary and treat with Kmeta, after which I can decide if copper, or reduless, or other steps are required. I know there is always a risk of mercaptans forming, and the batch being faulted beyond recovery. On the other hand, others have often cured H2S in secondary successfully.

What I don’t know or have sufficient winemaking experience to judge is whether I am getting in a knot over some innocuous H2S gassing off during primary that isn’t that unusual and will just pass. Or whether I should be taking more aggressive counter-measures sooner.

I had a prior H2S problem in another red wine ferment with too much heat and leaving the gross lees too long and that wine is probably unrecoverable although I set some aside to see what age does to it after going through some of the more drastic copper steps - it really stank at its worst. This is a fraction as much, although much earlier in primary.

Any experience/thoughts appreciated. And yes, I know by chucking that pomace in there I was into uncharted territory and might have stressed out the yeast and the kit-designed balance for fermenting, that coupling that with using RC-212 instead of the EC-1118, and potentially starting a co-ferment with MLF might have played into that. Just trying to crayon outside the lines?
 
I primarily make kits. I have only encountered a H2S smell once, and, like yours, it was slight. In my case, I simply fed more nutrients and aerated the must (like you did). The smell dissipated and the resultant wine was fine.

I have a bigger concern for your procedure, namely, that you introduced MLB to a kit wine. I have no first-hand experience, but Tim Vandergrift says that doing MLF on a kit wine "will end in tears."
 
I primarily make kits. I have only encountered a H2S smell once, and, like yours, it was slight. In my case, I simply fed more nutrients and aerated the must (like you did). The smell dissipated and the resultant wine was fine.

I have a bigger concern for your procedure, namely, that you introduced MLB to a kit wine. I have no first-hand experience, but Tim Vandergrift says that doing MLF on a kit wine "will end in tears."

I’m not suggesting that “one trial makes a rule”, but I did ferment a kit wine on skins from one of my VP41 coinoculated grape batches in ‘16. I ran chromo tests on the kit wine along with the grape wines, it never budged off of its very bright malic spot. Left it in the carboy for a year to make sure it was stable and bottled it with no issues. It’s one of my best kit wines.

Hopefully, the OP’s wine will enjoy the same fate.........
 
I’m not suggesting that “one trial makes a rule”, but I did ferment a kit wine on skins from one of my VP41 coinoculated grape batches in ‘16. I ran chromo tests on the kit wine along with the grape wines, it never budged off of its very bright malic spot. Left it in the carboy for a year to make sure it was stable and bottled it with no issues. It’s one of my best kit wines.

Hopefully, the OP’s wine will enjoy the same fate.........

I agree, one trial does not make a rule, but that is a very interesting (and useful) data point. I also hope the OP has similar outcome!
 
Thanks guys ... to the extent there might have been an MLF introduction hopefully when I sulfite at first racking it gets snuffed, or if I see any torpedoes firing later in secondary I’ll feed as an MLF and I’ll leave it in the carboy for a good long run of bulk aging. Maybe Santa will bring me a chroma kit if I promise to follow instructions better next year. As for tears ... from Tim’s point of view I don’t see much upside for him suggesting tweaks to his products - don’t they want to deliver as promised and minimize risk, not be criticized for leading risk-takers on? And I do appreciate they engineered the ph, TA, sulfite etc.,. Not to be thrown out of whack by me. If I did start an MLF my understanding is I might have to punch the ph back down with an acid addition. We’ll see. No tears here if I made an error, I’ll try and man up. I’ve made worse mistakes. Luckily I seem to forget most of them after a few years. Lol. Rookie errors? Geoff
 
Sounds like you have it under control, whenever I swap RC212 into a kit, I always add a half dose of Fermaid as 212 has a much higher nutrient demand as compared to the EC1118 normally supplied.
 
That is reassuring.

As soon as I smelt sulfur I hustled out to the local wine and brew store for some Fermaid. I agree with you, if I pitch RC-212 as a substitute again I will feed it nutrients at onset of ferment and 1/3 depletion as with grape musts.

Geoff
 

Latest posts

Back
Top