View Full Version : Another sulfur aroma thread

06-17-2011, 05:09 PM
Using the search tool, I read a lot of info here before posting this. But posting anyway to see if anyone can help advise me on my specific mead.

The mead in question was made 13 days ago.

Popped the top today to check to SG and smelled a bit of sulfur smell. Not crazy strong, but definitely present. Took a very small sample and the gravity was .998, down from 1.112. Tasting the sample and swirling in the glass, I didn't pick up any sulfur that I could detect through the mead's aroma at this early stage. The mead seems to have a lot of yeast still in suspension as it looked almost milky.

The recipe for the mead was:

15.87 pounds of acacia honey.
Enough water to reach 5 gallons total approx.
8 grams of Lalvin QA23, rehydrated with 12 grams of Go Ferm.
Pitched at 68, fermented from 68-70F.

3 minutes of pure O2 was used at pitching.
12 hours after pitching, 4.5 grams each of DAP and Fermaid K were added. Stirred vigorously and 3 min. of O2 added again.
When gravity reached 1.096(24 hours after pitching), added 2.8 grams each of DAP and Fermaid K.
When gravity reached 1.070(60 hours after pitching), added 1.8 grams each of DAP and Fermaid K.

36 hours after pitching, added 5 grams of potassium carbonate. I don't trust the litmus papers I have (yeah, I know, buy a pH meter). They're from MoreWine.com. But, these are the readings I had from them:

Must before fermenting: 6.0.
12 hours after pitching: 3.0 (but that's the minimum with these papers).
24 hours after pitching: same, 3.0.
36 hours after pitching, before adding 5 grams of potassium carbonate: 3.5-3.6.
40 hours after pitching, 3.0 again.
60 hours after pitching, 3.0 again.
13 days after pitching, still 3.0.

Initial water had 386 ppm bicarbonate.

So, long thread, sorry, but wanted to post all of the facts. Given that I don't really trust these papers and don't have the money for a pH meter at the moment, should I have used more potassium carbonate? Could that low pH be what caused the hydrogen sulfide? That yeast is listed as throwing off low levels of hydrogen sulfide with proper nutrients. Don't think I underdid the nutrients. Also, I was heavily degassing the must by stirring strongly with a drill attachment up to 1/3 sugar break.

Another question: Is 8 grams of yeast enough? I'm used to pitching much larger amounts of yeast in beer brewing. Would the yeast have been less stressed if I pitched 2 packets, 16 grams total?

For now, what should I do? I don't want to use copper. From what I read, I think it was Wayne that said that removing the mead from the lees can help as they may still be throwing sulfur. So, perhaps I should rack? I'm not fond of the idea of splash racking because of oxidation, so I was thinking of just regular racking to remove from the lees.

We head to the sea mid week next week. So, I was thinking of doing that: racking, then just leaving it until we return home ten days later and see if it's gone. Like I said, it's not crazy strong, so I don't wanna take drastic actions. I saw Medsen recommending yeast hulls. Is that a good idea for this stage? I don't have yeast hulls, but I do have some dry yeast of various sorts. Would just boiling it to kill it and adding that be like adding yeast hulls?

Anyway, advice would be appreciated.

Cheers. (p.s., I'm a patron now, see?!)

06-17-2011, 05:35 PM
Hey Matt,

Thank you for your Patronage, I'm sure you will get every cent's worth!

OK, have you tasted this stuff yet? It's not going to be near finished, but tasting can help you dial it in. When you taste it you're trying to detect any overly chalky or acidic notes. You'll get the acid on the tip and middle of the tongue and the chalk on the sides and cheeks, probably in the front of the mouth as well. You're just looking to see if it is really acidic/tart. 3.0 seems pretty acidic for that honey, but who knows.

Your yeast quantity at pitch time was fine. If the Starting brix is over 26 then I double up and increase my water and Go-Ferm in the yeast slurry accordingly. Did you atemperate prior to inoculating with your yeast slurry?

If it seems acidic, and it's not chemical sharp, astringent, salty or metallic, add a little more K-carbonate and test again. If you can shift that pH toward a less acidic character I think you'll be doing fine.

Did I miss the current gravity?

Enquiring minds want to know,



06-17-2011, 05:56 PM
SG is .998 at the moment (OG was 1.112). Still has yeast in solution, but I'd guess it's pretty close to done. Should I be adding potassium carbonate this late in the game? Thought it was for earlier on.

I did taste it. I wasn't looking for a chalky tasty exactly, just sort of sampling, so I couldn't say. I'd have to taste it again to give a more accurate comment on that.

The brix was over 26, right? Wouldn't 26 = 1.104? This was 1.112. So, should I have used more than 8 grams of yeast?

I did adjust the temp in the rehydrating solution. Added 200 ml or so of must and let it sit for 15 minutes. Then pitched.

Thanks for the help Oskaar. Sure I'll get my money's worth on the site. Already have even before I paid!

Chevette Girl
06-18-2011, 10:14 AM
Any time you need to adjust the pH is an appropriate time to add potassium bicarbonate. It's possible that the acidity is what caused the yeast to make stink in the first place (which is pretty amazing considering the bicarb already in your water!), but since they're mostly done now at .998, adding the potassium carbonate now would be mostly for taste, in case it's tasting too acidic. Although fixing the pH might prevent any remaining yeast from expressing their displeasure by releasing any further stink... If you're lucky, the sulphur will come out with a little aeration/agitation like it did for my pumpkin mead, I ended up splash-racking it into a carboy and then leaving the airlock off for a day or two, stirring it every few hours... If you give your must a good stir and the smell goes away or lessens significantly and then only comes back slowly, it means whatever's causing it is volatile enough to come out so it'll probably be fine with a little airing out. Also boiling up some bread yeast and dumping that in might absorb some stink. I think that helped a little with mine, but it was airing it out that really fixed it. There's a small risk of oxidation (mine seems not to have oxidized perceptibly) but I'll take that taste over sulphur any day.

06-18-2011, 10:56 AM
Thanks Chevette Girl.

What I'm thinking of doing is flushing a demijohn with CO2 and splash racking into that. Seems to me the point of the splashing is just to splash and shake that hydrogen sulfide out, not to get actual O2 into the mead. So, I figure that might be a good compromise. I took another smell last night and it's not so pronounced. The first smell was after the fermenter was closed for ten days, so I guess it built up and was released a touch when I popped that lid. We'll see.

Thanks for the pointers.

I won't be adjusting the pH at the moment. I was talking about whether I should have used more potassium carbonate earlier on rather than just the 5 grams, not adjusting for taste. This one's going to have sour cherries in it, figure I'd adjust the taste at the end, not this early on.

Chevette Girl
06-18-2011, 11:49 AM
Yes, in this case the splashing is to dislodge the sulphur compounds, not to introduce oxygen (since mine was still degassing at the time I wasn't worried anyway), flooding the dj with CO2 sounds like a good plan :)

If you're expecting your remaining live yeast to do something with the cherries when you add them, I'd recommend testing the pH shortly after you add them, the cherries may well raise the pH a bit and provide some amount of buffering, but if the pH stays under 3.0, I wouldn't be too surprised it gets stinky again, I don't think you under-fed it so my first suspect would be the pH.

From what I have read (here and several wine reference books), most yeasties don't like a pH lower than 3.2, and with your strips you don't know for sure how much lower than 3.0 your is... but no, you probably didn't want to add much more initially than you did, ideally you'd add some at the beginning of your fermentation, then wait till it goes down too low again, then add some more, lather, rinse, repeat to maintain a healthy environment for your yeast. You don't want to add TOO much up front because yeast do prefer an acidic environment (which is why a lot of wine recipes add acid up front), just not THAT acidic. And each step where you adjust pH, you don't want to change it TOO much as sudden changes may also tick your yeasties off.

And here's the grain of salt: although I did study biological processes just like this in university, I haven't managed to get my own pH meter calibrated yet and my local brew shop only started carrying the strips AFTER I bought the meter, and so I have never checked the pH of a single batch of my own creations. But when you rule out everything else, blame what's left... :rolleyes:

Good luck with your must! And if it smells less every time you open it up, you're probably going to be just fine as long as you give it a good agitation before you head out (have fun!).

Medsen Fey
06-20-2011, 03:03 PM
Could that low pH be what caused the hydrogen sulfides
...should I have used more potassium carbonate?

I think it is possible. There has been much study done on yeast producing H2S, and pH has not been found to be a major factor in the studies. Still, yeast behavior varies quite a bit between strains, and even the same strain will have different behavior in different musts, so there is a lot of room for questions. Of course, meads have hardly been studied at all.

In my experience, I have run into some batches that were producing sulfur odors that didn't improve with more nutrient, but did get better when I brought the pH up to a less stressful level. That is strictly anecdotal and not any kind of a trial. However, it makes me believe that during active fermentation, if sulfur odors are being produced and the pH is low, it may be helpful to bring the pH up a little.

Don't think I underdid the nutrients.
Following hightest's SNA yields about 150 ppm nitrogen for the yeast. To me that is a little on the low side, especially for a must with a gravity of 26 Brix. I think providing 50% more than you did might have made a helpful impact.

Another question: Is 8 grams of yeast enough?
Since you aerated, that is enough yeast. The fact that fermentation completed supports that.

For now, what should I do? I don't want to use copper. From what I read, I think it was Wayne that said that removing the mead from the lees can help as they may still be throwing sulfur. So, perhaps I should rack? I'm not fond of the idea of splash racking because of oxidation, so I was thinking of just regular racking to remove from the lees.

I saw Medsen recommending yeast hulls.

The first thing I would do is a splash racking. That will agitate off some of the volatile H2S. Just as importantly, it will add some oxygen to the mead. Yeast/Lees are very reductive in nature and that promotes the development of sulfur. Some oxygen to raise the redox potential will actually lessen the chance of sulfur odors. This is why they do battonage for lees aging. The oxygen may also activate some of the phospholipids in the yeast membranes making them bind sulfur compounds more readily.

You don't have to worry about it oxidizing a traditional mead. They are not easy to oxidize in the first place, and with it still being cloudy with yeast, you won't have a problem. So I allow it to have some aeration with racking.

If that doesn't clear the odor, I'd treat with copper. I typically rack with a copper scrub pad attached, but you can stir with some copper tubing, or if you want to be precise, you can use copper sulfate. While you have a cloudy mead, any excess copper will bind to yeast and precipitate out.

If you read the thread hydrogen sulfide a thorough review (http://www.gotmead.com/forum/showthread.php?t=13256&highlight=sulfide) (Patron's area) you'll see some other strategies mentioned. Yeast hulls can help, but I wouldn't use boiled yeast as that is adding a lot of other stuff than the hulls. I'd use the yeast hulls. If you can get it, a yeast-hull-based product called reduless, is specifically made for this purpose. Kieselsol, a fining agent also can work. Personally, I've found copper to be quicker and easier in most cases.

06-21-2011, 10:19 AM
Thanks everyone! All good advice and I'll make sure to refer to the other thread about hydrogen sulfide as well in the future if I have a problem.

For the time being, though, I'm not going to do anything at all. I checked on the mead 2 more times just to see if I was smelling anything and the sulfur smell is gone. Can't find a trace of it. With everything to do to get ready to leave on vacation, I also just didn't have any time to clean the demijohn I was going to use, which would have required some soaking. Just ran out of time. But I'm not worried. Like I said, the sulfur smell isn't there. I think what happened before, is it built up a little as I didn't pop the top for 10 or 11 days. And, it wasn't very strong even then, just a slight touch of it.

Anyway, we'll see when I get back on July 2nd what's going on. I'd rack it if I had had the time to deal with everything, but I just didn't. Had a deadline today and had to work some long days to make it and just ran out of time. Relax, don't worry and drink some homebrew while letting the mead age, I say.

Thanks again, everyone. Cheers!

07-10-2011, 04:42 PM
So, racked this mead onto 7 kg of sour cherries today and took a sample. No trace of sulfur at all. Not in the fermenter, not in the glass. Great!

The mead tastes surprisingly good for 5 weeks old. Not too hot. Pretty mild but not boring.

Anyway, no worries. Everything's good.