Some Facts About Sulfites

Some Facts About Sulfites

Potassium Metabisulphite is a stable source of sulfur dioxide in winemaking. The use of sulfur compounds is not a recent innovation. The great Dutch shipping empire popularized the use of sulfur in the 16th century by refusing to ship any wines not treated. They insisted on sulphites because sulphite treated wines were the only ones that survived a long sea voyage without turning to vinegar.

Sulphites work by releasing free sulfur dioxide, which inhibits yeast, mold and bacteria. It does this in two ways: one, it kills some of the organisms outright and two, it blocks the surviving organisms ability to reproduce.

Sulphites are also added directly to wine after fermentation, to help prevent oxidation. Oxidation in wine follows the same pattern that you see in the cut edge of an apple- the wine turns brown and takes on a flat 'cardboard' taste. Sulfur binds with the oxygen in the wine and prevents this damage.

Many people worry that they may be allergic to sulphites. True sulphite allergies are very rare. It is more likely that they have a histamine reaction to red wine, or that they have been over exposed to sulphites in the past.

Some facts that might clear up any misunderstanding about sulphites:

Sulphites are a recognized food additive. Their use is controlled by the federal government
All commercially available wines contain sulphites. The legally allowable amount is 70 ppm (Parts per Million)
Nearly all dried fruits and meats contain sulphites. Raisins, for instance, have up to 250 ppm
Sulphites are produced by all grape based wines naturally during fermentation, up to a level of about 10ppm. Even with no addition of outside sulphites, wines will still contain them.

This is not to say that sulphites are totally benign. People with asthma or emphysema should avoid inhaling sulphite powder or the gas that comes off the solution. It can act as a bronchial constrictor, aggravating any breathing problems. Also adding extra sulphites to wine is of no benefit, as it can spoil the flavor, giving it a 'burnt match' smell.

The upshot of sulphite use is this: without sulphites you'd have to drink the wine quickly, before it spoils, probably within a month or two.

ANOTHER EXCERPT:

Sulfites have been used in many
countries for many years. The US requires warning labels on
wines with a certain level of sulfites, because of a very small
percentage of people (mostly asthmatics) who can suffer life-
threatening allergic reactions to sulfites. Many other countries
do not require this warning label, which might account for your
confusion. In other words, the sulfites are present in the
European wines sold in Europe; they just aren't necessarily
listed on a warning label.

Sulfites occur _naturally_ in wine at low levels. You will NOT
find an entirely sulfite-free wine. However, there are wineries
that do not _add_ sulfites to some of their wines. Some of these
have sulfite contents that are below the labelling threshold
(<10ppm) so they do not carry the warning label. However, even
some wines with no added sulfites can have levels of 15-20ppm!

Although the maximum legal levels of sulfites in many countries
are around 300-350ppm, in practice, the levels are much lower --
say around 20-50ppm. These levels are also much lower than the
levels found in many foods. For example, dried fruits have a
legal limit of 2,000ppm. You'll also find higher levels of sulfites
on fast food french fries and salad bars.

The reason I mention this is that it is important to be sure that
you actually do have an allergy to sulfites (have it tested by
a physician), and not to some other component of wine. Sulfites
are commonly blamed for "wine headaches" for example, when they
are rarely (if ever) the cause -- alcohol and histamine-like
compounds are much more likely culprits. If you are allergic
to sulfites, you will have to be careful of a wide range of
foods -- and some don't always have obvious warning labels.

Unfortunately for some, white wines tend to have higher levels
of sulfites than red, and wines with residual sugar (e.g. most
white zinfandels) have higher levels of sulfites than completely
dry wines.

Finally, please note that wines labelled "Organic" may contain
added sulfites. The only guarantee is to find a label that
actually says the wine has "no added sulfites". Even then,
you should check that the wine doesn't carry the warning
label (which would at least mean that the level was <10ppm),
or check a fact sheet for the wine to find the actual level.
Most producers of "no added sulfites" wines are happy to
provide this type of information.