Screw top wines being ruined by sulphidisation?

Hi Rod,
This only applies if the sulfide problem is a H2S problem and the H2S has not yet interacted with the alcohol. But if any source of sulfide present in the wine has interacted with the alcohol and transformed into mercaptans and disulfides swirling the wine glass and aerating the wine doesn’t really “cure” the wine of its sulfide problem. If mercaptans or disulfides are now the cause of the problem the only way to treat the wine is with a poisonous solution.

Salute

What ever happened to the Australian Wine Research Institute's investigation of the relative performance of 14 different wine closures, which considered a range of physical, chemical and sensory parameters?

I have not seen new data in ages....

Thoughts?

Millions of bottles of wine sealed with screw tops rather than corks could be ruined by the smell of rotten eggs, experts have discovered.

Tests suggest that more than one screw top bottle in 50 sold in Britain could be affected by the problem, a chemical process called sulphidisation. The figures throw into doubt claims by the wine industry that screw tops are safer and more reliable than corks.

The annual International Wine Challenge event tested tens of thousands of wines from around the world including around 9,000 with screw caps. It found 2.2 per cent of screw top bottles suffered from sulphidisation and other problems connected with the wine not breathing.

The effects leave a whiff of sulphur, likened by some to burning rubber, rotten eggs, burnt matches or stink bombs. Around 100 million screw top bottles of wine a year are sold in Britain and the figure is rising as it becomes a popular alternative to cork.

Almost 90 per cent of New Zealand wines now arrive in screw top bottles. Warren Adamson, the UK director of the New Zealand Wine & Grape Industry, said: "This is the first time any official figures have come out with regard to the screw top's sulphide problems. These are helpful for our producers. However New Zealand wines were only 1.7 per cent affected, below the average."

But a wine taster Martin Isark said: "Although the smelly problem is a small percentage, with over a hundred million screw top wines hitting our shelves that's potentially a big stink."

The NZ winemakers have retaliated to this article and versions of it that appeared in our newspapers. They say "the cap criticism stinks". They say that "accusations that screwcap bottles can cause wine to smell like rotten eggs have been labelled a beat-up driven by supporters of the traditional cork sealed bottles."

Two articles are at the following links ....
Marlborough Express and
The New Zealand Herald ...
where both had poorly reported regurgitations of the original article the day before.

Petter Godden of the Australian Wine Research Institute is quoted in the Herald article. He says
" ...winemakers here (in NZ) are doing an excellent job of controlling excessive sulphides which are produced during fermentation." He says the issue was a beat-up by the cork lobby and close associates of it and an orchestrated campaign to undermine the use of screwcaps and potentially damaging to the New Zealand industry where up to 90 per cent of wines used screwcaps.

In the Marlborough Express article, John Forrest is quoted. He says
.... cork sealed wines still had twice the problems with sulphur as screwcapped wines, and the figures quoted confirmed that.
"Twice as many cork bottles would turn into stink bombs than screw caps," he said. The presence of sulphur smells was a wine making fault rather than a closure problem, and "transitory unstable sulphides" in the wine, which most people would not notice. It could be helped by decanting the wine he said.

And it's true, sulphides in wine was a problem long before screwcaps came along.

Personally, from the very beginning, I believe that the “experts” knew that screw caps might have some problems. Someone in the wine industry (sorry I don’t remember who) said (something like this) - that it’s great to have an alternative enclosure, but we are not letting science (or our understanding of what goes on inside a bottle of wine) catch up to this “new and innovating” technology. Being a passionate amateur winemaker it’s the “science part” that interests me the most.
Some people here like to distinguish faults and make a distinction between winemaking fault and enclosure faults. From the time my shipment of grapes are delivered to the end of my driveway to the day I bottle the wine and seal it with an enclosure, every decision that is made, every technique or operation that is performed as far as I’m concerned is a winemaking decision. If someday, (I hope just like Howie) I grow my own grapes than I’ll also tack on to this list, every decision that is made in the vineyard, every technique or operation performed in the vineyard is also a winemaking decision. The only time that I would consider it an enclosure fault is if for some reason “beyond my control” the enclosure failed to do the job it was suppose to do.
Yes it is true that sulfides have been a problem way before screw caps. And IMO will always be a concern of a winemaker. But the trick is to keep it at “bay or check” (How many times have you heard the phrase “checks and balances” when it comes to winemaking - this is what it is all about). In my previous post I talk” about the sources of sulfides in wine. One source of sulfide is decomposing yeast cells, and eventually during a wines life it’s going to see some time on its lees or sediment. How much time? All depends, it’s a winemaking decision.

Salute

The presence of sulphur smells was a wine making fault rather than a closure problem, and "transitory unstable sulphides" in the wine, which most people would not notice. It could be helped by decanting the wine he said.

And it's true, sulphides in wine was a problem long before screwcaps came along.

Spot on, Sue!

Sulphidisation WAS an established problem prior to alternative closures.

According to the Australian Winemaker of the Year in Australia, Addam Eggins, sulphidisation is nothing more than sloppy winemaking, and has nothing to do without the seal. By the way, all the wines Adam makes goes under screwcap.

Adam is also not only one of the "Show Judges" in Australia, but also on the panel that oversees quality control for the industry board, and he teaches/advises other winemakers.

He maintains, in the typically blunt and outspoken Ozzie manner (similar of course to the Kiwi manner ), that if there is a sulphur issue in any wine, it is specifically and solely the fault of the winemaker, not the seal.

He goes on to explain that any competent and experienced winemaker can become aware of the chemical processes involved, and deal with them accordingly.

This issue is not a fault or failure of the seal: it's the fault of the winemaker. The seal does precisely what it is supposed to do.

Hoke - we agree. That's just about what I said in the 3rd post in this thread.

Late at night and looking through some UK sites.......here is an interesting article/an attempt to discuss!! Jamie has posted here quite a few times. He is quoting some stories/reports that were in the UK press. I hope it is OK to post this here as it seems relevent to this thread.

http://www.wineanorak.com/screwcap_defence.htm

Thanks Bob for posting Jamie Goode’s article. I think that the table will be of some interest to the home winemakers who visit here. .

Salute

Thanks Victor, I was not quite sure if I should post or not as Jamie is referring to UK press reports. But it makes interesting/educational reading eh.

I found and dug up this thread because I've encountered a rash of sulphury wines lately -- all screwcapped wines. It is matchstick, which I always take as SO2 - not rotten egg. I've never smelled H2S in wine, not that i know of, actually, other than doctored samples.

I've smelled it at various levels in over half of the screwcapped wines I've had in the past 2 months. That's a lot of sulphury stink!

this week it was Gruve. Gruner Veltliner. I've had it recently in Chat Bonnet Blanc, Henry of Pelham Sauv Blanc, Fat Cat Chardonnay from NZ, and a few others.

I'm concerned. THIS IS NOT MY IMAGINATION -- I had no reason to expect this. I had never read about the problem before, and we barely talked about reductive character in my Sommelier training. I think what's happened is that there's a bunch of screw capped wines on sale here now, and I'm trying them. They've been in the system for a couple of years, sitting in warm stores under the lights. Could this exacerbate the problem?

I agree it is less a problem than TCA, and that sometimes decanting takes care of it, but it really lingers other times.

As I was explained to by a winemaker with awesome technical creds, the winemakers need to use less SO2 in screwcapped wines (or other wines that have a perfect seal). I assume that is because there is a reductive state in there, with not enough O2 to scavenge the excess free S? So the screwcap doesn't cause the problem, I guess, but it is a factor for sure, at least as I understand the chemistry going on there.

It has been years 20 since I took chemistry.

2 days ago i had an 03 Annie's Lane Riesling under screwcap (it is reduced for sale this month at ANBL - our gov't monopoly) -- and I like it, but it has a golden green colour due to age, and some wacky odd smells that are either S related or a combo of Riesling-diesel and whatever else??...combine that with lime and a paraffin/minerally/grassy/floral countenance and it is an interesting drink.I'm sipping some now - 2 days after opening.

i think some folks would return it...

I figured that there had to be some kind of down side to screwcaps to get rid of TCA. I finally ran into someone who then e-mailed me numerous articles concerning the reduction problems with Stelvins. I have a decent backround in chemistry and I still had to read these articles about 3 times to really understand what they were saying. My take was that much can be done in the winemaking process to deal with most of the H2S issues. Most of the data so far deals with the tin/saran liners. They seem to have no OX ingress for the wine. They also talk about a Saranex liner that does have some OX ingress. It would seem that this is closer to a "perfect cork ". We shall see. All I can say is that I have probably had 2000 wines under Stelvin in the last year and less than 1% seemed to have any reductive problems.

I have no idea what I'm smelling in these wines - am I confusing H2S with SO2? I'm confused.

I'd like to see a perfect scientific explanation, but, in searching around, I'm getting varying opinions and explanations that don't jibe.

I found a long explanation about reductive development of wines that totally contradicts everyone else, by Richard Peterson, here:

http://wine.appellationamerica.com/wine ... earch.html

he is over on the right panel -- the comments section

I wouldn't care too much about this if it were not affecting me so frequently -- the sulphury wines I'm getting...

I have no idea what I'm smelling in these wines - am I confusing H2S with SO2? I'm confused.

H2S is hydrogen sulphide. It smells like rotten eggs - or, if you ever visit New Zealand, it's the smell that permeates through the active thermal regions that tourists flock to, e.g Rotorua. Once you've smelt it, you will never forget it.

I don't get H2S with wines that are reduced (screwcap or not). It's more of a 'struck match' smell.

OK I'm glad to hear that -- this is what I've always thought

so these articles talking about H2S in screwcap wines -- I think they must be full of s**t

and what are we actually smellign when we smell struck match? SO2 vapur? pure S gas

I think there's some confusion here - the struck match is a classic descriptor of reduction - which is not the same as SO2. Reduction refers to the presence of a whole slew of volatile sulfur-containing compounds - H2S is the stinky rotten eggs one, that's really bad, but fortunately rare - then there are mercaptans, disulfides and so on. The struck match is the one I most commonly encounter in wine. It's a classic white Burgundy character.

I think there's some confusion here - the struck match is a classic descriptor of reduction - which is not the same as SO2. Reduction refers to the presence of a whole slew of volatile sulfur-containing compounds - H2S is the stinky rotten eggs one, that's really bad, but fortunately rare - then there are mercaptans, disulfides and so on. The struck match is the one I most commonly encounter in wine. It's a classic white Burgundy character.

a whole slew of volatile sulfur-containing compounds? that's too vague for me

so what compounds, exactly, are we smelling, then? If it is not SO2? I thought mercaptans only happened much later on in the aging process when there is nothing left to scavenge, so more complex S compounds form? And it REALLY stinks, like skunk farts

struck match seems like such a pure, single, repeatable, smell -- I always thought it was one specific compound, and since burning is oxidation, I figured it was SO2 vapour...or dust???

i should clarify, too, why I'm so interested in the chemistry

i'm a metallurgical engineer by trade - I stopped 10 yrs ago to become a wine writer

but i worked 12 yrs in a steel mill - where i was VERY FAMILIAR WITH THE SMELL OF S!

we spent a lot of effort removing it - even adding it sometimes

a melt shop smells like hell would smell if it existed

i also know the smell of iron oxide very well - not just rust, but the smell when molten steel hits air and gives off various oxides that end up in slag

Am I the only one who thinks that sulfur is a good thing?

It kills the bacteria, and it gives you an extra layer of protection against the threat of premature oxidation.

[Of course, I guess there's the question of whether a properly screw-capped wine can oxidize prematurely in the first place, but maybe that's a different discussion.]

Some of my favorite producers, who make some of the most ageworthy wines in the world, like Manfred Prum & Toni Bodenstein, leave massive amounts of sulfur in their wines.

I've had old Prum and it is amazing...wish i could buy it here in Atlantic Canada

i guess by 10 yrs S is a non-issue!

i went on a Sommelier trip to Germany last year for the VDP fest in Mainz, and we did a tasting of top trocken wines with a minimum of 10 yrs age....wow!

Hi Craig,
If you scroll up the page a little bit, you will find a post by Bob Parsons who cross references a very well written article and it does include a table that you might find interesting.

Here’s another link
http://www.etslabs.com/scripts/ets/page ... pageid=350

Salute

That's a nice article, thanx! I missed it because I arrived late in this thread.

So it sounds like ethyl mercaptan is the only matchstick smelling compound.

This article says ethyl mercaptan is rare.

I think they are wrong when it comes to screwcaps wines. Based on my last 2 months of work, I think it is VERY COMMON!

Hi Craig,
Here’s the article Bob Parsons cross posted and I was referring too;

http://www.wineanorak.com/screwcap_defence.htm

Most wine drinkers do not have the chemical background that you have. So if one experiences a wine with a “high concentration” of mercaptans or thiols, terms like “burnt matches“, “burnt rubber”, “sewage” or “rotten egg” (which most people are familiar with and can relate too) will most likely come up.

Salute

Am I the only one who thinks that sulfur is a good thing?

It kills the bacteria, and it gives you an extra layer of protection against the threat of premature oxidation.

[Of course, I guess there's the question of whether a properly screw-capped wine can oxidize prematurely in the first place, but maybe that's a different discussion.]

Some of my favorite producers, who make some of the most ageworthy wines in the world, like Manfred Prum & Toni Bodenstein, leave massive amounts of sulfur in their wines.

Nathan,

The problem may be, with respect to screwcaps, if there is too much SO2 in the wine, then oxygen starvation could cause reduction. It's not an issue of sulfur dioxide additions being a good or bad thing.

Um.



Not that I'm gloating, mind you....but I told you so.

I sincerely apologize in advance for being right....then getting the boot from this BBS for saying so. What an idiot I was.


Not that I'm bitter, mind you.








Sorry! What was I thinking?