Wine + Sustainability with Elizabeth, Vol. 3

For many years, sulfites have been a topic of much discussion and debate amongst wine drinkers and producers. One could say that it is one of the most polarizing topics in wine. Today we are breaking down what sulfites are and what their role is in winemaking.

Sulfites and Headaches, Debunked.
Currently, there is no medical research data showing that sulfites cause headaches. A number of studies have been linked sulfites and asthmatic responses (symptoms include hay fever and hives), but few of these address sulfites in wine.

According to Clark Robert Smith, winemaker and a recognized leading authority on the enhancement of wine structure, “There is no such thing as a sulfite allergy. SO2 is too small a molecule to be recognized by a T-cell, and the human body produces a gram per day of sulfites.  There are other sorts of possible sensitivities such as a deficiency of sulfite oxidase enzyme in the liver, but these are exceedingly rare and to my knowledge have only been demonstrated in five U.S. citizens. For these people, the tiny amount of sulfites in a wine is the least of their worries.”

If you suspect that sulfites are causing your headaches, try eating some dried apricots. If this doesn’t result in a headache, than sulfites are probably not the culprit. Dried fruits typically have 2000mg of sulfites. Meaning that a 2-ounce serving should contain about 112mg of sulfites. The levels of sulfites in wine average 80mg per liter or about 10mg in a typical class of wine.

Other factors that can lead to headache from wine:
– Dehydration from alcohol and sugar present in wine
– Histamines and Tyramines
– Tannins

To avoid headaches you can incorporate any number of the following methods:
– Drinking less wine
– Drinking wine with food
– Hydrate and drink plenty of water, alongside wine

The History of Sulfites
When did the use of sulfites in wine begin? Some have said that this practice had been in use as far back as ancient Roman times, but in actuality, widespread use of sulfites is a relatively recent thing.

The earliest references of sulfites being added to wine have been found in German texts from the Middle Ages and relate to barrel sterilization and not to wine preservation. What we do know is that by the end of the 18th century, the burning of sulfur wicks, a practice developed by Dutch traders, to shield and stabilize wine in barrel, manly for transportation purposes, was commonplace.

The use of sulfites, as we know it today, began in the late 19th century. Sulfites became readily available at the time when the first oil refineries appeared, alongside the petrochemical industry.

What are Sulfites?
Sulfites or sulfur dioxide is a fruit preservative widely used in dried fruits, as well as wine. It is also produced by the human body at the level of about 1000mg per day.

Yes, all wines contain sulfites. Yeast naturally produce small amounts of sulfites during fermentation, usually up to 20g per liter, although it could be higher, depending on the strain.

In winemaking, there are three common forms of Sulfur:
– Sulfur, S: Elemental sulfur is present in proteins and used on grapes to prevent rot.
– Sulfides, H2S and mecaptans are the rotten egg and skunk smell produced when yeast and bacteria reduce S to H2S, in other words, reduced sulfur.
– Sulfites, SO2 (sulfur dioxide) and all its forms. In other words, oxidized sulfur. There are 3 forms of sulfites in wine: Molecular sulfur dioxide (SO2), Bisulfite (HSO3) and Sulfite (SO3).

For more information about the differences between sulfites and sulfides, check out these videos from UC Davis: Sulfites and Sulfides.

In wine, sulfites exists in two different states, free and bound. The three forms of sulfites mentioned above, exist in the free state. The bound state is when these forms combine with compounds such as phenols, acetaldehyde and sugar.

Why are Sulfites used?
Sulfites are a common winemaking additive that can take the form of a gas, liquid, powder, or tablet. They may be used at any stage of wine production: as the grapes come into the winery, when the grape juice and wine ferment, or when they are being moved around or bottled. Because of their antimicrobial properties, sulfites are often used at the beginning of fermentation to stun or eliminate wild yeasts and bacteria carried in on the grape berry, so that the winemaker can inoculate his/her chosen strain. Sulfites are regularly used to sanitize equipment and stabilize wine at bottling. Their antioxidant properties shield wine from contact with oxygen and destroy those enzymes that cause a browning of the grape juice (similar to a sliced apple that has been exposed to the air).

Some natural or sustainable growers will not add any sulfites at all, others will add a dash at most, generally at the bottling stage. IF they do add any sulfites it is usually because of commericial realities such as releasing a wine early, trouble with a vintage, worries about transport or storage.

The use of sulfites differs from country to country and is influenced by culture. In Germany, Austria, and even France, the use of sulfites is a lot more tolerated today, than in Italy.

  • Since 1988 the US and since 2005 the European Union (EU) require any wine containing more than 10mg per liter to state, “contains sulfites.”
  • In the EU, the legally permitted amount of sulfites for a wine, per liter, is 150mg for red, 200mg for white, and 400mg for sweet wine.
  • In the US, the legally permitted amount of sulfites for a wine, per liter, is 350mg.
  • Certified Organic wine in the US cannot contain any added sulfites, while Organic EU winemakers can.
  • Vitners who add elemental sulfur to grapes on the vine can call them organically grown, but winemakers who add sulfites to organically grown grapes anytime during the winemaking process can’t.