2011 Ferments

[Cellar_Rat]

Brian,

This link may be of use. Adding more sulphite than necessary should be avoided. In my case at 50ppm this should have been fine.

http://www.nanaimowinemakers.org/Steps/H2S_Issues.htm

It is interesting that the opening comment on this link is "Reduced sulfur compounds (those formed in the absence of oxygen) are a perennial problem in winemaking"

I am beginning to think this might be 'air phobia'. Wine is a continually moving breathing thing. Lack being able to breathe causes problem's commercially with screw caps. Is it the problem here?

[SiSandrine]

CuSO4 on order, hopefully the local HBS will have some ascorbic acid

Pete - In case they don't if you have holland and barrett they sell Vitamin C powder (pure ascorbic acid).

[DerekSmith]

What a thread, and some great links on H2S - feels like I have been reading for days...

A have a bit more info that might help to fill in the 'cause'

I have made wines for many years, yet never had the foul H2S adorn any of them.

Then last year, I made red from home grown grapes but fouled up by mistakenly adding Sulphite + Sorbate at the start (lack of ATD, I looked at the pack and saw sulphite and completely missed the sorbate) consequently, I had a hell of a job getting it started, and when it eventually took off, I was greeted with the stench of garlic which gradually abated through the ferment.

The white grape I made had no such misfortune, fermented well and turned into a wonderful drop of paint stripper (I had picked too soon in an attempt to beat the birds). However, despite the acidity, not a hint of H2S.

This year I cured the bird problem, but closing up the tunnel meant that humidity was too high and rot started to attack the bunches, I hung on as long as I dared - the skins were yellowing and stalks starting to brown with good brown seeds, so I harvested with a crush brix of 20.8%.

I hand sorted the bunches to eliminate any rot and sulphited at crush (just as I did last year). I pitched a really strong starter of K1-V1116 and fermented on the skins (just as last year) for 2 days.

At this point the only differences between this year and last year was that this year -1. I had allowed the vine to over produce, -2. the grapes were overripe and -3. I was using K1-V instead of a generic 'Red Wine' yeast.

At 2 days I pressed. One DJ full of free run and the second was half free run and half press juice. The ferment continued rapidly and five days later ended abruptly. My records show -

20 Sept - 16:00 - ferment nearly stopped.
DJ No.1 - 0.988 -- refract 5.9% -- 20.6C - est 12.7% abv
DJ No.2 - 0.986 -- refract 5.8% -- 20.6C - est 13.3% abv
taste fresh but spritzy and too warm to get full effect - nicely sharp.

On 18 Oct they were both clearing nicely, so I decided to rack - and as the song goes - then it hit me...

DJ No.1 was heavy with the stench of rotten eggs, and DJ No.2 was many times worse: i.e. the press juice had produced more H2S than the free run juice.

I splash racked them both and gave them both a vigorous stirring with a copper tube before sulphiting quite heavily.

The stink has faded considerably to the point where I can start to make out the smell of the wine. If they continue to improve I might even taste them soon.

I had read 'somewhere' that overripe grapes are prone to low nutrient content, but even so, I had thought that two days on the skins would have been enough to feed the yeast, but I am guessing the combination of overripe grape with a killer yeast K1-V1116 was enough to turn the yeast cannibal on its own lees.

Anyone else have any thoughts?

Derek

[DerekSmith]

Reading the two interesting papers that Steve (NorthernWiner) posted, suggested to me that the 'recipe' for H2S development is probably set in place early on - certainly by the time the crush starts its serious ferment. The paper by Angela Lee Linderholm made it clear that the formation of sulphide is an essential part of a yeasts metabolism and that it will be being produced throughout the whole of the ferment. A multitude of conditions in the wine however, seem to influence the ability of the yeast to hang onto this vital metabolite, and in some conditions large quantities of it can be lost into the wine to complex with numerous other components.

In the acidic (i.e. low pH) wine, some of the released sulphides are converted into H2S gas which is very volatile and easily swept out on the CO2 and into the headspace, giving us the tell-tale stink that all is not well.

So do we have here an opportunity of an early indication of trouble to come?

If we can detect H2S in the carbon dioxide stream early in fermentation, then we have at least a chance to try to correct the situation before significant levels of sulphide compounds have a chance of being built up in the wine.

A very simple check for the presence of H2S is Lead Acetate paper, which turns grey and then black in the presence of H2S. By putting a strip of this paper into the stem of the airlock, we could see if, or how quickly, it turned black, and we might be able to use this as an early indicator of a problem.

Has anyone heard of this approach before, or have any thoughts on the idea?

Derek

[NorthernWiner]

It is interesting that the opening comment on this link is "Reduced sulfur compounds (those formed in the absence of oxygen) are a perennial problem in winemaking"

I am beginning to think this might be 'air phobia'. Wine is a continually moving breathing thing. Lack being able to breathe causes problem's commercially with screw caps. Is it the problem here?

I saw this post a few days ago but haven't had time to reply (I've been on holiday. Isn't it funny how vacation time seems to be more hectic than day-to-day work?)

As you point out, reduction refers to the absence of oxygen, but lack of oxygen isn't always intentional on the part of the winemaker. You may be diligent about punchdowns and aerating your must, but H2S can still form in the bottom of the fermenter where the lees don't really see much "action." I once got some good advice once from a fellow home winemaker who suggested that punch downs should also include stirring up all the nasty stuff from the bottom to give them some air contact at the surface. I do that and it seems to work. Or maybe I've just been fortunate not to have had too many issues with H2S.

[NorthernWiner]

If we can detect H2S in the carbon dioxide stream earl in fermentation, then we have at least a chance to try to correct the situation before significant levels of sulphide compounds have a chance of being built up in the wine.

A very simple check for the presence of H2S is Lead Acetate paper, which turns grey and then black in the presence of H2S. By putting a strip of this paper into the stem of the airlock, we could see if, or how quickly, it turned black, and we might be able to use this as an early indicator of a problem.

Has anyone heard of this approach before, or have any thoughts on the idea?

I've never heard of this approach, but then again, I do all of my red wine fermentation in open top containers. Well, more or less open top. I usually loosely fit a lid or towel over the top to keep insects and dust out.

My wife has a better nose than I. She is usually the first to point out when something might be getting a little stinky. In that sense, she is my early warning H2S detector.

[DerekSmith]

When I punch down, I vigorously stir the whole fermenter, but I do this to remove any temperature gradients top to bottom. The consequence though is that although I am careful to exclude air by covering the cap and covering the fermenter, I will inevitably be introducing a little oxygen and 'life' into the lees every time I p.d.

The idea though that the lees is anaerobic and so is 'rotting' is no more apt than the fact that the wine is also anaerobic and so by the same definition is also 'rotting'. Perhaps a larger difference is that the wine is moving so nutrients are easily diffusing, while in a static and possibly stratified lees, the opportunity for nutrient diffusion may be much reduced, leading to the over production of sulphide and its conversion into H2S by the low pH of the wine?

Whatever the cause, we should remember the paper by Angela Lee Linderholm and the statement that sulphide is an essential metabolite of yeast - they make it all the time - it seems that in certain circumstances they fail to fully utilise it before it diffuses out into the wine.

Derek

[Cellar_Rat]

Might be worth racking between runs?

[DerekSmith]

My wife has a better nose than I. She is usually the first to point out when something might be getting a little stinky. In that sense, she is my early warning H2S detector.

Thanks Steve,

Thanks to your wife's 'better' nose, you may have answered the questions that the lead acetate paper idea was aimed at i.e. 'Are stinky wines, stinky early in their lives?' and 'Is the early stinkyness masked by the H2S being vigorously scrubbed out by the escaping CO2?'

The fact that your wife's superior nose can detect H2S in problem wines in vigorous ferment suggests that the answer to both these questions is YES.

This agrees with Linderholm's assertion that all yeasts have to make sulphide to live and to be able to fight off the toxic effects of the anaerobic fermentation byproduct - alcohol.

Another situation however, confirms for us that it is not the yeast which is the problem, but the media it is growing in.

This year I made up one large starter bottle of K1-V and pitched it into three musts. The first was crushed red grapes from my poly-tunnel crop, the second was crushed white grapes, also from the poly-tunnel, and the third was a crush of red Italian Merlot grapes. In all of these three brews, the K1-V will have made sulphide in order to survive, indeed, in the Italian Merlot, It would have had to have made much more because the sugar level and the final alcohol level was so much higher. Yet despite this, only the white wine went stinky, and in hindsight, I recollect that after I pressed it, the white had a none too pleasant 'nose' to the evolving gas, while the reds both smelled of sweet ethanol.

So, it is not the yeast, but something in or missing (or both) from the must, and this imbalance is present right from the onset of fermentation.

One further thing we know is that this effect did not come from the lees, it was present throughout the fermentation but was being 'washed out' by the vigorous purging of CO2, but when the ferment ended, the H2S collected because it had no CO2 to purge it out any more. This suggests that a CO2 purge through an airstone as fermentation draws to an end might sweep out residual H2S from the final struggling throes of the dying yeasts as their food gives out and they are progressively poisoned by alcohol.

Finally, we know that whatever the troublesome agent was, it was present (or absent) to a greater extent in the pressed juice than it was in the free run, because my second DJ was far stinkier than the first (free run) DJ. This at first face is counter intuitive, because I have always found that the yeast ferments much better on the skins - I assumed this to be because the skins contained easily available nutrients - but perhaps not?

Perhaps simply the white was lacking in nutrients because the grapes were overripe? And had I paid attention to my nose and added nutrient when I first detected a 'whif', my white would not have become the mess it is today ? ?

Derek

[robwrx]

A weird one for you!

So after much deliberation I decided to try MLF on my Grapefest Merlot and Sangiovese and at the beginning of October I pitched the MLB.

Nothing happened. For two weeks nothing happened and I figured the conditions hadn't been right and assumed the attempt had failed. I was concerned that the wine was still on the gross lees and had not had any sulphite added since the 5ml per 5 litres pre ferment, so I vacuum racked and added potassium metabisulphite. There had been no airlock activity for sometime and no sign of bubbles whatsoever.

Twenty days since introducing the MLF and following racking and adding 5ml per gallon pot met I've got small bubbles rising in the jars and collecting in the necks. I'm pretty sure it is not CO2 as two lots of vacuum racking should have degassed the wine quite well so I can only assume it is MLF taking place.

Any thoughts?

Rob

[NorthernWiner]

Sounds like MLF to me.

[Cellar_Rat]

Derek,

I am sorry if you have already mentioned this, but was nutrient added to the white? You might benefit from Yeast available nutrient testing - I am not sure how complex this test is though - is it something can do at home?

[robwrx]

Sounds like MLF to me.

It seems rather weird to me that having spent two weeks in theoretical ideal conditions nothing happened but after racking and adding SO2 the MLB decided to start doing it's thing.

Also, I kept a good record of what got inoculated and what didn't and I have a half gallon jar of merlot that appears to be going through MLF without my adding any bacteria. Is this possible?

[NorthernWiner]

...I have a half gallon jar of merlot that appears to be going through MLF without my adding any bacteria. Is this possible?

It's absolutely possible. Just like yeast, lactic acid bacteria are in the air all around us. Commercial ML bacteria is a fairly recent innovation, having only become available in the last few decades. In the thousands of years prior to that, MLF "just happened" without any intervention on the part of the winemaker.

[robwrx]

It's absolutely possible. Just like yeast, lactic acid bacteria are in the air all around us. Commercial ML bacteria is a fairly recent innovation, having only become available in the last few decades. In the thousands of years prior to that, MLF "just happened" without any intervention on the part of the winemaker.

Thanks for the info Steve. I thought I had read somewhere that MLF could happen spontaneously but I wasn't sure.