No bubbling and Sulfur smell in secondary ferment

[Kcass]

Hi there everyone,

My partner and I have transferred our Shiraz into our carboy for the secondary ferment. It was at the Goldilocks temperature the whole Primsry and was at 1.000 SG when we transferred. It's been in the carboy for 4 days but there is no bubbling, nor is there bubbling in the airlock. We decided to do a hydrometer test (1.000). BUT it is still has the fermenting smell like Sulfur or rotting eggs... we were going to rack again off the lees in a few days but should we be doing it earlier and adding SO2 to clarify, reduce the smell and improve the wine? We had an active and seemingly spot on primary, so we are concerned...

In other words, can it be saved and where did we go wrong?

 

[Yooper]

Hi there everyone,

My partner and I have transferred our Shiraz into our carboy for the secondary ferment. It was at the Goldilocks temperature the whole Primsry and was at 1.000 SG when we transferred. It's been in the carboy for 4 days but there is no bubbling, nor is there bubbling in the airlock. We decided to do a hydrometer test (1.000). BUT it is still has the fermenting smell like Sulfur or rotting eggs... we were going to rack again off the lees in a few days but should we be doing it earlier and adding SO2 to clarify, reduce the smell and improve the wine? We had an active and seemingly spot on primary, so we are concerned...

In other words, can it be saved and where did we go wrong?

Not having bubbling is great- it means the wine is just about finishing. However, sulfur odor is bad. You shouldn't have it at all, even in primary, and it suggests stressed yeast.

The first thing to do is "splash rack"- that is, rack the wine letting it splash into the new vessel so that the sulfur blows off. If it persists, it's time for the big guns (let's hope not!). And some yeast nutrient now (dissolve it in a little water first), and then splash rack and see if it helps. You have to act right away, or the wine will be ruined by H2S.

Look at this page by an expert (scroll down) to see how to correct H2S (hydrogen sulfide) before it's too late: http://winemaking.jackkeller.net/qa.asp

 

[Kcass]

Thanks Yooper.

I've read elsewhere, that we need to wait for MLF to finish before adding anything. Given our wine is at SG 1.000, is it okay to proceed with the splash rack, wait until tomorrow to see if still smells, and then would you add copper sulfate, or kmeta/campden tablets?

We wouldn't want to add yeast nutrients if it has finished fermenting, but we can add ML nutrients to help it settle?

Cheers,
Em

 

[Kcass]

I don't think that link is working for me?!

 

[LedBoots]

I don't think that link is working for me?!

Copied the text from the site

How to Treat Hydrogen-Sulphide

Hydrogen sulfide does much more than impart off-smells and flavors to wine. Hydrogen sulfide can be detected by smell in quantities as low as 2 parts per billion. It can usually be dissipated during the first 2-3 weeks after its production begins by racking and aerating the wine. After several weeks, it tends to react with other components in the wine to form less volatile mercaptans, which themselves can be further oxidized to disulfides. These latter compounds are almost impossible to remove from wine by stripping methods, and their presence in the wine makes it undrinkable. Both mercaptans and disulfides have a notable skunk-like smell.

Hydrogen sulfide is usually formed after fermentation has concluded and detected when the wine is racked. If the hydrogen sulfide has not sat in the wine too long, it can be treated with a maximum measure of 0.5 ppm of copper, the amount contained in 0.75 ml of a 1% solution of copper sulfate pentahydrate added to a gallon of wine. The hydrogen sulfide should be gone within two days and the wine can be treated normally. However, it will take about 3 rackings, 20-30 days apart, to remove all excess copper from the wine. If not removed, the copper itself can taint the wine.

The amounts of copper sulfate pentahydrate used are so small, and the risks to fatally damaging the wine by adding too much are so real, that it is impractical to treat small amounts (less than 5 gallons) of wine. The preferred treatment is still to add sulfur dioxide in the form of potassium metabisulfite solution (see Measuring Additives in Winemaking) and then rack the wine with plenty of aeration to drive off the H2S.

A proprietary compound called Sulfex can also be used to treat hydrogen sulfide formation. It comes as a 10% slurry in water and is added to wine at the rate of 0.5-5 grams per gallon. It is insoluble and settles out without leaving any traces in the wine if subsequently racked properly at least twice. I have never used it but have heard it works well.

 

[Yooper]

Thanks Yooper.

I've read elsewhere, that we need to wait for MLF to finish before adding anything. Given our wine is at SG 1.000, is it okay to proceed with the splash rack, wait until tomorrow to see if still smells, and then would you add copper sulfate, or kmeta/campden tablets?

We wouldn't want to add yeast nutrients if it has finished fermenting, but we can add ML nutrients to help it settle?

Cheers,
Em

MLF hasn't started yet, I assume. Have you added any sulfites at all to the wine at this point?

 

[jgmillr1]

You've likely got a couple issues going on.

First, sounds like you are smelling H2S from stressed yeast. The splashing method risks oxidizing your wine and is not well controlled. You should deal with this sooner rather than later because the these sulfides can be treated easily now, but if you wait they can form disulfides and mercaptans that are more cumbersome to remove. Your best bet is to get the copper sulfate solution and carefully measure out the right amount. For a 1% copper sulfate solution, add 3.7mL to 5 gallons to get 0.5ppm Cu in solution (copper is toxic in high concentration and this is the legal limit allowed by the TTB). Stir or swirl it in thoroughly. The reaction is almost instantaneous. Wait for a day for any residual H2S odor in the carboy to dissipate, pull a sample and see if it still stinks. Add the same amount of copper sulfate again and repeat daily until the odor is gone. The reacted copper in solution will form copper-sulfide black specks that will settle and be left behind on the next racking.

Second, your yeast got stressed from insufficient yeast nutrient. Some strains are more needy than others (RC212 and Montrachet, for example). They are struggling and the fermentation is sticking as they split open their own yeast cells for nutrients, thereby generating the H2S. Next time, be sure to add yeast nutrient at about 1/3 and 2/3 through the fermentation to support the yeast's needs. If there is much sugar left to ferment at this point, you could add a little DAP, say about 0.3g/L, and give it another week or two to complete. Don't want to add too much yeast nutrient at this stage because if the yeast can't use it, something else will! If it is a fully stuck fermentation, you could restart the fermentation with a strong finisher such as EC1118.

Be careful about starting malolactic while there is still sugar present since this can result in some acetic acid (vinegar) being produced. Don't add any sulfites until malolactic is done.

Cheers!

 

[Kcass]

Hi there,

So we splash racked last night and this morning the smell has largely gone!

Should we wait for add MLF nutrients and wait to add sulphites? Or should we add sulphites immediately to avoid oxidation?

We added sulphites before the primary ferment, but not since then.

Is it safe to restart the fermentation? We are sitting at SG1.000 and we really want it at .998 before bottling right? Is the wine certainly 'stuck' if it doesn't move below this mark? I'm assuming this is something we want to get onto ASAP to avoid spoilage?

Sorry for so many questions. This is a fascinating process and we are ejoying the challenge. We also VERY MUCH APPRECIATE your communication.

Em

 

[Yooper]

Hi there,

So we splash racked last night and this morning the smell has largely gone!

Should we wait for add MLF nutrients and wait to add sulphites? Or should we add sulphites immediately to avoid oxidation?

We added sulphites before the primary ferment, but not since then.

Is it safe to restart the fermentation? We are sitting at SG1.000 and we really want it at .998 before bottling right? Is the wine certainly 'stuck' if it doesn't move below this mark? I'm assuming this is something we want to get onto ASAP to avoid spoilage?

Sorry for so many questions. This is a fascinating process and we are ejoying the challenge. We also VERY MUCH APPRECIATE your communication.

Em

The wine may go as low as .990 so you have some time. Degassing/splash racking may be enough to keep the yeast happy since the sulfur seems to be dissipating.

If you're planning on MLF, don't sulfite yet. If you're trying to avoid MLF, you can sulfite now.

Did you press the grapes yourself or buy them already crushed? Just curious- it really doesn't matter but I'm wondering about why the fermentation wasn't healthy.

 

[Kcass]

We started from fresh grapes, crushed them with sanitised hands and a sieve and then pressed them with muslin cloth. We transferred them from primary ferment with a siphon, whereby we had to suck the wine through a few times. That's the only thing I can think of that we've done out of line.

The temperature has been great, acidity, etc all been fine. But the smell has gone.

I'm assuming it's not worth restarting the ferment to get it down to .998?!

 

[Yooper]

We started from fresh grapes, crushed them with sanitised hands and a sieve and then pressed them with muslin cloth. We transferred them from primary ferment with a siphon, whereby we had to suck the wine through a few times. That's the only thing I can think of that we've done out of line.

The temperature has been great, acidity, etc all been fine. But the smell has gone.

I'm assuming it's not worth restarting the ferment to get it down to .998?!

It should keep fermenting now, so wait about a week and check the SG again if you're worried.