About Sulfites (SO₂)

 
What are Sulfites?

Sulfite is a word used to describe several forms of sulfurous acid salt, including sulfur dioxide, potassium metabisulfite and sodium metabisulfite. Natural sulfur commonly occurs in the vicinity of volcanoes and hot springs. The manufactured sulfites used in winemaking are generally made from the residue of natural gas and petroleum crude.

Though there is evidence that sulfur has been used in winemaking since the days of the Egyptians and the Roman Empire, most data suggests that the “blue smoke” in accounts of winemaking was the burning of sulfur that was used in the cleansing of storage vessels before they were filled with wine and that sulfur was not actually added to the wine.

It wasn’t until the after World War II that the Germans initiated the practice of using the cleansing abilities of sulfites as a major ingredient in the wine to guard against microbes, stabilize color, and help prevent oxidation as they moved their winemaking into a more mechanized production.  As the wine industry has evolved over the last 50 years into a “better wine through chemistry” approach, this procedure has now been embraced by most commercial wineries and wine educators and is embedded in the training of contemporary winemakers.

Very few winemakers have the skills to make wines without added sulfites. It is only a few pioneers in winemaking, or those of us with old family traditions and techniques that continue to have the knowledge to make high quality wines without the added sulfites.  And with high standards, meticulous sanitation, and attention to details, we continue to follow this tradition that is deeply rooted in our family history.

What do sulfites do?

Due to its reactive nature most of a sulfite molecule joins other substances in the wine. This part of the sulfite is called “bound” sulfite, and since it is bound up it usually can’t be detected except at high levels. A smaller part of the sulfite molecule can’t find anything to join and wanders freely through the wine, ready to bond with traces of air or other substances or organisms. It is this free sulfite that can be more easily smelled and tasted or cause a sulfite reaction.

For most measurements the bound and free sulfite fractions are added together to get what is called a “total” sulfite level in the wine. These are measured in parts per million abbreviated as “ppm”. Although the legal limit in the US is 350ppm most wines with added sulfites are in the 50-200ppm level. Since some sulfites are naturally occurring in the grape the federal law requires the label to state CONTAINS SULFITES if the wine has more than 10ppm.

Why Sulfites Are Used To Kill Yeasts and Contaminants

Wineries with large productions normally take in grapes from multiple vineyards and from various regions. Many of these grapes are machine harvested which can cause them to be split or damaged in the vineyard. The resulting slurry of juice and grapes and vineyard debris can spend hours in a truck in hot climates traveling long distances and can quickly start growing unwanted organisms.  Sulfites added at the crusher once at the winery either inhibit or kill the wild yeasts, bacteria, and microbes. This then allows the introduction of a commercial wine yeast that is resistant to sulfites to complete a rapid and uncontaminated fermentation.

All of our grapes are carefully handpicked from the small vineyards of dedicated growers and the undamaged fruit is immediately delivered to us within hours in refrigerated trucks. The quality and freshness is equal to or better than most table grapes that you can purchase in the fruit section of your local supermarkets.  The grapes bunches are all individually inspected by hand and any imperfections are discarded so that only the highest quality fruit is used. No microbes or bacteria are allowed into the process at the start, so there is no need to inoculate with a killing agent. Grapes are immediately crushed and the fermentation is started in small containers where they are monitored several times a day.  Once the conversion of sugar to alcohol is well under way the natural antiseptic action of the alcohol content of the wine will not allow human pathogens to survive.

Sulfites are also widely used to reduce oxidation (i.e. “browning” from exposure to air). Large hose runs and huge tanks of wine can expose the wine to oxygen during racking and bottling. Barrels and tanks must be kept full to minimize air exposure. This is very labor intensive for large wineries and may be difficult to do if they have a thousand barrels of wine.

We use inert gases (nitrogen, argon or CO₂) to keep our settling tanks full for a few weeks and then wine is moved in a closed system with gravity from the tanks to barrels that are purged with inert gas before filling. When wine is racked we use a very expensive specially designed piece of equipment that pressurizes the barrel with nitrogen and allows the wine to flow freely out the hose and into the next gas filled barrel. This system is very slow and expensive but minimizes contact with oxygen and keeps the wine structure from being disturbed by going through a pump. 

Bottling is all done by hand with the bottling tank being filled with gas before the wine is added and each bottled is then hand filled with nitrogen before it is filled with wine and immediately corked.

Are Sulfites a Problem?

There is a lot of confusion about the health effect of sulfites. And there really have not been any definitive studies done on this issue. Getting a headache after drinking wine is usually the result of one of three factors: sulfites, amines, or overindulgence. We all know when we’ve had too many, but the cause of a throbbing head after one glass of wine has been the subject of just a few studies. White wines with their lighter colors will oxidize much more quickly and readily than reds and therefore will normally contain more sulfites to protect them from oxygen. Sweeter wines, with some unfermented sugars still present, will usually contain significant amount of sulfites to keep the yeast from fermenting those sugars after bottling.  Reds, in general will have tannins from the grape skins and oak barrels that contain polyphenols that act as an anti-oxidant and protect the wine from oxidation and help to stabilize the color. 

Allergic Reactions

A very small number – about 1% to 2% -- of people will have an allergic reaction to sulfites, which can consist of nasal congestion and sneezing, skin hives or wheezing and difficulty breathing. People who have asthma and/or allergies to aspirin are particularly sensitive to sulfites and could even have a serious reaction. Thus in 1986, the FDA passed regulations requiring companies to list on product labels sulfating agents that occur at concentrations of 10 parts per million (ppm) or higher. Wines without added sulfites must be tested by an independent laboratory before “no added sulfites” can be noted on their labels.

Red Wine Headache

Tannins
Some people may find that they can drink white wines but are getting headaches from the red wines. This may very well be a sensitivity to tannins. Tanins are the favonoids in wine that tend to make your tongue feel ‘dry’ after a sip. A few small scale studies show that tannins cause the release of serotonin, a neurotransmitter. High levels of serotonin can cause headaches and that may happen to people especially those who also suffer from migraine headaches. But tannins are also present in some very common foods such as tea, soy, and chocolate and most people do not get headaches from them.

Histamines
A more common culprit may be the histamines.  Since histamines are naturally occurring in the grape skins, the longer grape skin contact during fermentation of red wines can make the histamines 20-200% higher in red wines than in whites. This can cause some problems for people, particularly those with allergies or asthma. But reds will also contain more histamines, which are naturaly occuring in the grape skins. Th histamines can be concentrated in red wines because of the longer grape skin contact during fermentation. If you are having problems with red wines and not white wines it may very well not be a sulfite problem.

Prostaglandins
Some early research also points to prostaglandins - substances that contribute to pain and swelling, as a possible source of the 'red wine headache'.  You may find that you can drink some reds but not others. Try different grapes, from different growing areas. Keep a journal of how you react. You will probably know after half a glass and within about 15 minutes if you are going to have a problem. Some studies suggest that if you take one aspirin BEFORE you drink or taste wine it may keep the swelling from starting.

Can you tell the difference?

We believe that the natural wines taste better. Wines without added sulfites have bright, clean, fruity flavors, earthy characteristics, spicy herbal essences, and traces of minerals from the vineyard soils. We add nothing but grapes, yeast, and a malolactic fermentation starter. We do not fine or filter our wines or manipulate sugars and acids. We rely on our relationship with our growers to give us grapes picked at their perfection.

Unfortunately some winemakers can be excessive in their use of sulfites, which has the effect of masking delicate flavors, assaulting the nose, and causing headaches and allergic reactions to those especially sensitive. We think that excessive sulfite use embalms wines, diminishes its bouquet, suppresses the fruit flavors, and can leave unpleasant bitter aftertastes.

Even moderate sulfite use can have a sterilization effect that in essence kills delicate fragrances and flavors and deadens the taste of wine by destroying the vitality of its living natural yeast and organisms.

Wine without sulfites is still alive. The raw grapes are alive at harvest and the yeasts are alive and they continue to grow during fermentation. And without the fining and filtering you are receiving all the benefits of the yeast, and the nutrients and minerals of the original fruit. It isn’t necessary to improve on the natural processes of fermentation, and human interference is best kept to a bare minimum to create a clean and delicious healthy product.

Copyright 2007 · Lost Mountain Winery ·  Sequim, WA