Sulphur...

[JohnM]

I posted this on another website, so might as well post it here too.

I was very bored yesterday and was thinking about sulphur in whisky... Anyway, very unscientifically, I looked at the amount of posts on whiskymag mentioning sulphur/sulfur year by year. Obviously if there's a topic specifically about sulphur you're going to have more posts, and I didn't really look to see if some of the occurrences were quoting previous posts... so it all probably means nothing. Nevertheless...

First mention was once in 2002

2003.............. 4
2004...............4
2005...............16
2006...............32
2007...............80
2008...............169
2009...............79
2010 to April......23

Another thing I didn't take into consideration was web traffic on the site year by year.

So, pretending my stats are in some way relevant for a moment, the discussion on the subject seems to have taken off in 2007. So were there more sherry cask whiskies released as time went on, were distilleries releasing more tainted casks to satisfy the demand or are people imagining there's more sulphur-tainted casks out there since Jim Murray brought it up (whatever year that was)?

This probably isn't statistically significant. Maybe there was just more web traffic, maybe people were just discussing Jim Murray's editorial, maybe...

[DavidH]

Fascinating. What's the connection between sherry casks and sulphur?

I've heard a couple of times recently (eg at the Barry Crockett tasting) that sulphur is a natural product of distillation and the point of the copper in the stills is to create copper sulphate that can be siphoned off. But that's pre-maturation. Does sherry put it back in?

And would anyone like to describe what they mean by "sulphur"? Is it a hint of burning match, rather than a rotten egg aroma?

[JohnM]

Fascinating. What's the connection between sherry casks and sulphur?

I've heard a couple of times recently (eg at the Barry Crockett tasting) that sulphur is a natural product of distillation and the point of the copper in the stills is to create copper sulphate that can be siphoned off. But that's pre-maturation. Does sherry put it back in?

And would anyone like to describe what they mean by "sulphur"? Is it a hint of burning match, rather than a rotten egg aroma?

The Spanish government at some stage banned the bottling of sherry abroad, so the casks for whisky had to be exported sans sherry. To stop them going off, some are treated with sulphur and this can get through to the whisky. They burn some kind of sulphur candle within the cask.

[JohnM]

... I think it can come across as either the burnt match or the eggy sulphur, according to what I've read. Maybe only one of these is associated with cask treatment.

[JohnM]

Actually, doing some further reading, I think some ex-sherry casks are sulphured anyway. A sherry maker might do it before using the cask again, or someone else using the cask. But they're not that interested in what was in the cask before, so they would rinse it out if they were using it themselves, eliminating the sulphur influence.

And the char on bourbon barrels can extract the sulphur from the spirit in early stage maturation.

[DavidH]

I'm learning a lot here...

But back to your question. You need a control term to graph alongside your sulphur data. How about "caramel"? that would show how much of the peak is due to people just becoming interested in discussing every tiny aspect of whiskey. It should track with Jim Murray's influence too.

[IrishWhiskeyChaser]

Yes Sulphur is a strange one ... There are 2 types as ye both refered to.

However the Sulphur found from the distilation process should not be overly pronounced as any distiller worth their salt would not have let it through in the first place and if they did it would of been on the light side. It is reckoned that this type of low level sulphuring gives whisky it's meaty charachteristics which can be an added bonus for some.

However the second sulphuring effect can be very prominent and comes from the casks and will only be found after tasting during the maturation period. Mainly found in sherry casks but can be any wine cask that has been treated. Wine producers need to sterilize casks before shipping to distilleries and use sulphur candles to do this. They need to sterilize to prevent any bacteria growing in the cask which is a particular problem for wine casks in transit. Sulphur candles are still one of the best ways to do this but I am unclear whether it is from a candle used too long or the distillery not cleaning the barrel well enough to prevent over sulphuring of the whiskey.

Burnt matches is the most obvious sign and eventhough I don't mind a slight taste, the more intense this taste becomes it actually ruins the whisky. I find that most Distillery releases have very low levels of this but Independent releases sometimes can have higher levels and is usually only noticable in small batch or single cask releases.

I have one theory on this though ... and it is only a theory so open to correction. Over the last decade the whisky industry has seen enormous growth for single malts especially single cask and small batch versions. Therefor there has been strain on stocks therefore some distilleries maybe scraping the barrel so to speak to fullfill demand. Due to this Independent bottlers are getting less and less opertunity to pick and choose and can't even buy from some distilleries anymore. Therefor they release what they have and some are unfortunately less than favourable in taste being overly sulphured.

For example I went through a phase of getting loads of Glenrothes and adored all the Distillery releases I had but found that many independent bottles I got were obviously sulphured.

[IainB]

You might also want to correllate the presence of sulphur with the presence of volcanic ash in the atmosphere. Just a thought.

On a more relevant point, they do regularly say that the copper in the still removes some of the traces of sulphur and for that reason even continuous stills have copper heads. Against that isn't there one canadian distillery where all the equipment, including some pot stills, are stainless steel and from what I've read they don't seem to have much of a problem.

As regards the casks, I wonder why it only seems to come up in the context of sherry and not other wine casks such as madeira, port etc.

[JohnM]

Yes, I think the copper in the stills fixes the sulphur in the distillate into copper sulphate.

[Willie JJ]

I have one theory on this though ... and it is only a theory so open to correction. Over the last decade the whisky industry has seen enormous growth for single malts especially single cask and small batch versions. Therefor there has been strain on stocks therefore some distilleries maybe scraping the barrel so to speak to fullfill demand. Due to this Independent bottlers are getting less and less opertunity to pick and choose and can't even buy from some distilleries anymore. Therefor they release what they have and some are unfortunately less than favourable in taste being overly sulphured.

I think this is a good point Adrian. I think it was also made worse by the fact that from the end of the 70s until the mid-90s the industry was reducing output and capacity. That has meant that in the last few years demand for malts has increased (both for singles and for blending) as supply of 10yo+ malts was falling. I think that has had a detectable effect in the quality of some of the whisky that has reached the market.