Sulfites and Sulfides

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From the course by University of California, Davis

Wine Tasting: Sensory Techniques for Wine Analysis

136 ratings

University of California, Davis

Wine Tasting: Sensory Techniques for Wine Analysis

136 ratings

With its roots in ancient cultures as early as 6,000 BC, wine has long been part of the human experience. Today, increasing worldwide interest in wine and its complexities and varieties has created an international market valued at $304 billion annually. For the learner who is just getting started in the study of wine, this course will help you take the first steps toward understanding the physiological process of wine tasting. The first module will explore types of wine and help you set up your own tasting. You’ll also begin to build a sensory vocabulary. In module 2 you will review classic wine types of the world and set up flights of specific wines. Later we’ll examine the various faults and defects that can appear in wine as well as techniques for spotting problems. In week 4 we’ll delve into the complex world of wine and food pairings, and its “seven deadly sins.” The course will culminate in a peer review project in which you will apply the knowledge and sensory techniques you have developed throughout the course to assess a specific wine.

From the lesson

Common Wine Faults

Is there something wrong with this wine? This week we’ll examine the philosophy behind what actually constitutes a fault in wine. We’ll identify the most often-encountered faults and explain how to recognize them as well as determine what caused them. We’ll also examine the Old World and New World sensibilities toward some of these faults, and discuss how some so-called faults may really be attributes that contribute to a wine’s complexity. We’ll differentiate between a fault and a defect and examine the range of classic faults and their origins. You’ll learn techniques for spotting problems and create wine defect sniff standards to practice fault recognition.

Common Wine Faults Introduction1:10

Common Wine Faults7:19

Beauty is in the Nose of the Beholder4:58

Oxidation Faults4:33

Reduction Faults3:54

Oxidation and Acetic Acid Faults10:11

Sulfites and Sulfides4:06

Microbial Faults6:10

Common Wine Faults Summary6:17

Meet the Instructors

John Buechsenstein
Wine Appreciation Faculty
UC Davis Division of Continuing and Professional Education

[MUSIC]

As we've talked about, a lot of aromatic faults in wine relate to sulfur.

Some of them we call sulphites, and some of them we call sulphides.

And I thought of an interesting way to show you the difference.

Sulfites are used as a preservative in wine.

Actually, many people are of the opinion that you really can't make good wine

without sulfites.

We've been using them for hundreds and hundreds of years.

And sulfites come in the form of sulphur dioxide,

either as a gas or in a powdered form that can be added to wine.

And it's really, really a good thing to add sulfites to wine.

But sometimes sulfites are slightly in excess.

And it's when we smell them

that we say that they could be called the wine fault or a borderline wine fault.

Sulfides on the other hand, and I'm extenuating that word sulfides with the D.

So S U L F I D E S, are completely different form of sulfur.

Sulfides the most common ones that we smell,

are hard boiled egg or old eggs or rotten eggs.

Sometimes we can smell them in caramelized onions or garlic.

Or some sulphides we smell when we have first opened a can of canned corn.

And those are not very pleasant.

But just as a simple illustration let me show you a simple difference

between sulphites and sulphides.

So sulfites, or sulphur dioxide is a combustion product

between elemental sulphur and oxygen.

So if I were to take a couple of wooden matches and light them.

[NOISE] And forget to hold my breath [LAUGH]

that pungency that explodes out towards

you after you light a match is sulfites.

It's elemental sulfur burning in the presence of oxygen and creating SO2 gas.

And you're all familiar with that.

So now you know what sulfites smell like.

When you pick up a glass of wine that maybe has been recently bottled, and

to which sulphur dioxide was recently added,

and you say there's a little sharp pungency in there.

That's probably sulfites that you're smelling.

Or of course, someone could have made an error and added too many in the winery.

And then you can smell that pungent smell.

But here's what you do next.

Take these two burnt matches and

stick them in a wine glass, and put a little cover on them.

And let that wine glass sit for a couple of hours, and then come back to it.

So here I am, pretending that a couple of hours have elapsed.

And I'm going to come back to my glass and smell them.

And what do I smell.

I smell a little bit of charriness.

But more importantly, I smell a burnt sulphur smell.

So that's no longer that burst of sulphite

SO2 gas that we got when we first lit that match.

This is now a lingering residual smell of burnt sulfur.

Actually, sometimes people smell that at very, very low levels in wine and call it

gun flint, or a flintiness, or a minerality in wine.

[SOUND] But now you know what a burnt sulfur smell smells like in wine.

And we can find this in wine.

And it is called a reduction fault or a sulfur reduction odor fault.

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