Mittwoch, 21. Oktober 2009
Montag, 5. Oktober 2009
A look at sulphur in wine
Sulphites in wine are an essential part of the winemaking process. Increasingly, however, they are being blamed for causing adverse reactions in wine drinkers. Jeanri-Tine van Zyl investigates.
Using sulphur to preserve and prevent spoilage is not a modern trend. The Oxford Companion to Wine (OUP, 2006) notes that the mention of sulphur (referred to as brimstone) dates back to Biblical times - in the first book, Genesis, it is used in an act of doom on Sodom and Gomorrah. But the ancient peoples quickly realised that God's weapon could also be put to beneficial use - of which the preservation of perishables, such as wine, emerged as a most important discovery: "The operation of fumigating wine with sulphur is performed by kindling rags of linen dipped in melted brimstone, and suffering the steam to enter a cask filled... with that liquor," notes Beckmann and Johnston et al. in A History of Inventions and Discoveries (1846) on the use of sulphur dating back to Roman times.
In fact, the addition of sulphites in the preservation of solids and fluids has been so effective that their use is yet to be bettered in the modern wine trade. However, this longstanding method of preservation is now being challenged by the increasingly health conscious consumer, a new generation who are taking note of the additives in products and their effects. Points of concern are the impact of sulphites on those suffering from allergies, or sulphite intolerance, on the one hand, and the effect of sulphites on your state of being the morning after, with many tipplers questioning the role this additive plays in their hangovers.
A contentious issue
Delving into the subject proves to be contentious - a winemaker, who wishes to remain anonymous, admitted to it "not being good for you" but then quickly noting that sulphite levels in dried fruit, amongst other consumables, are much higher than those found in most wines. Sulphites do present a level of toxicity - but most of us are not particularly sensitive to its use in small concentrations and the adverse effects associated with such compounds can primarily be linked to those suffering from allergies, or asthma.
In contemplating the issue, it's important to be clear that there is no such thing as a sulphur-free wine as sulphur naturally forms during fermentation. Used as an anti-oxidant and anti-septic, extra sulphur can be added to freshly picked grapes in the form of metabisulphite (which is also found in other consumables such as fruit juices and dried fruit) at the beginning of the production cycle, but sulphur levels are also adjusted during production. The reason for this is twofold. Free sulphur reacts with oxygen to prevent the oxidation of wine, keeping it fresh and preventing browning, while bound sulphur in wine inhibits the growth of unwanted microorganisms, acting as a disinfectant.
Gains and losses
But how to address the consumer anxieties without it having a negative impact on wine? Neil Patterson, cellarmaster at Franschhoek wine farm L'Omarins is keen to explore alternatives. Though he admits he's on unchartered territory scientifically, he questions sulphur as the sole protector of wine, and is a proponent for no-addedsulphur wines. A sufferer of sulphite intolerance himself, Patterson relates how the area around his eyes turns into a red rash when he drinks a wine high in sulphur content. "I'll look like a panda," he says in explaining why he stands personally to benefit from producing wines that are generally lower in sulphur content. Last year, Patterson experimented with making a no-added-sulphur Chardonnay, aided by new purification technology Surepure.
This invention, in lay terms, makes use of UV radiation to inactivate microbes that can lead to wine spoilage. But although this can reduce the bound sulphur component, enough free sulphur would still be needed to prevent oxidation. "Oxidation remains a problem," notes John Loubser from top Constantia winery Steenberg, where the Surepure technology has also been tested.
This is reiterated by Jeff Grier from Villiera in Stellenbosch, where a no-sulphur added Cap Classique, Brut Natural, is produced. "The main problem happens at bottling, when wine is exposed to oxygen - Surepure doesn't really help with that." In the end you can produce a wine with no added sulphites, but the maturation period will be shortened, says Grier.
But given that the vast majority of wine is consumed within days, if not hours, of purchase is that really a problem? Producing wine without added sulphur is a fraught exercise, as no-added sulphur wines can be highly volatile. "We did research on producing a no-added sulphur Chenin Blanc, it tasted great in the tank and the day of bottling, but two weeks after bottling the wine goes darker and looses fruit," says Grier. Also, wines which haven't been subjected to added sulphur will react to oxygen quicker once opened and should therefore not be subjected to "airing practices" such as decanting, for example.
A QUESTION OF AGE
On the point of maturation, Patterson admits to playing it "safe" with L'Omarins' first no-added- sulphur wine to be released being a Rosé in the farm's new Protea range - as no-one buys a Rosé to cellar. While Grier is not convinced that there is a sure-fire way to cut out the use of sulphur without hampering aging, he thinks that the pressure coming from consumers for lower-sulphur wines has some benefits. When a winemaker produces a lowersulphur wine, he needs to be more aware of practices that might introduce harmful components to the wine. As Grier says, "if you know you can't just fix any problem by adding sulphur, then you become more mindful of your winemaking techniques." Clean cellars, healthy fruit and hands-on production are key.
"Good housekeeping becomes of utmost importance," echoes Patterson. And without revealing names, he alludes to this being difficult to achieve at certain mass-production plants where large volumes make it difficult to keep an eye on "triggers" that might cause need for added sulphur - such as ullage in tanks that can cause oxidation if not treated with additives.
But apart from putting emphasis on more diligent winemaking practices, Grier adds that more naturally produced wines retain more original flavour, and as grapes for lower-sulphur wines are often picked at lower pH levels, chances are that these wines will also be lower in alcohol - which is advantageous given the backlash that high alcohol wines are increasingly attracting. The bottom line, however, is that lowersulphur wines are going to be shorter lived.
Does this introduce a conflict between the average consumer who wants a wine to go with his TV dinner tonight and the serious collector? No, says Grier. Château Petrus is not going to change its recipe to suit the market whims for example, but lower sulphur wines are going to become a big issue. Says Patterson: "Some might say lowsulphur wines are a trend or a fad, but I believe it is the start of the future".
What to drink?
There is no clear recipe to follow. White wines usually have higher doses of sulphur dioxide, with Sauvignon Blanc, especially those with green pepper nuances, being notorious for this additive.
Red wines and bubbly are known to have lower amounts whilst Noble Late Harvest contain very high doses of sulphur dioxide. It has become compulsory in both South Africa and the European Union for wine labels to contain the wording "contains sulphites" or "contains sulphur dioxide" for wines that contain more than 10 milligrams per litre of SO..
The maximum amount of added sulphur is 160 mg/. in normal wines and up to 300 mg/. in NLH wines. Unfortunately law does not dictate exact amounts be printed on labels.
Are you allergic to sulphites?
Consumers should make a clear distinction between headaches and hangovers. If you are sensitive to sulphur, a headache is most likely to be triggered within hours of consumption, whilst a hangover is only felt the following day. Alcohol, causing dehydration, rather than sulphites, are the cause of hangovers. According to Dr Harris Steinman from the Allergy Society of South Africa, most common indications that you might be suffering from sulphur allergies include coughing, followed by shortness of breath, wheezing and a tight chest. Some consumers may experience a runny nose and, uncommonly, a rash. Dr Steinman also notes that asthma sufferers are particularly sensitive to added sulphites and should therefore be aware of consumables that contain sulphur dioxide such as wine, dried fruit, fruit juices and so forth.
A sulphur trigger should also not be confused with allergies to other compounds found in wine. Many individuals are also affected by histamine in wines. "Some individuals, and up to 45% of Asian individuals, cannot metabolise the alcohol and therefore will become sick on drinking wine, which is an enzymatic problem," says Dr Steinman, adding that few individuals may actually be allergic to alcohol. The degree of reactions may also vary as those caused by an enzyme problem can be dose-related: "It is possible that an individual's reaction will vary, for example, if he or she ate something containing sulphites that used up some of the enzyme, then drinks wine before the enzyme is replenished, then he or she could have a reaction at a lower dose than usual."