Over the past few years, the popularity of natural wines has grown significantly. At the same time, no other term in the wine industry has caused as much controversy in recent years as natural wines. The reasons for this development are attributable to the fact that no clear definition of natural wines and no governing body exist to this day to uphold any standards. In my opinion as a winemaker, the term has often been used by the industry as a marketing vehicle to convey trendiness, often without communicating a full understanding of its meaning to consumers buying natural wines.
Natural Wines vs. Conventional Wines
To better understand how natural wines may differ from conventional wine, I will touch on some key concepts that are a requirement for natural wines and then address one of the big controversies around natural wine: the addition of sulfites during the winemaking process. I will also address why less interference is not always better.
Natural Winemaking Process
First, one of the key tenets of natural wine is the belief that grapes destined to become natural wine must come from either organic or biodynamic vineyards and need to be hand picked during harvest, as opposed to machine-harvested. Secondly, these grapes are then fermented with native yeasts, often leading to a slower and gentler fermentation process.
Next, unlike conventional winemakers, producers of natural wines aim to minimize additives during winemaking. These additives include industrial yeasts, yeast nutrients, acids, sulfites, and a whole gamut of fermentation products that can reduce a wine’s shortcomings before it ends up in the bottle. Finally, conventional winemaking often includes adding fining products to adjust the wine shortly before bottling, followed by sterile filtration – practices not found in natural winemaking.
I previously worked at various wineries in Napa and Sonoma County, some that adhered to very limited interference during winemaking while others adhered to the same manipulation regimen year after year to minimize vintage variation and to appeal to the mass consumer market. As a result, I am a strong proponent of natural wine practices and believe that, in most cases, less is more. I also believe that such an approach will lead to wines with a strong character of their origin, especially in California Pinot Noir.
Most importantly, I consider the omission of synthetic pesticides in vineyards due to the growth in organic and biodynamic farming practices, the most beneficial outcome of the natural wine movement. In the United States, this is particularly relevant because a 2019 study by Nathan Donley comparing pesticide use in the United States to that of other countries found that the US used over 70 different pesticides that had been banned in the European Union. The study attributed this statistic to deficiencies in the US pesticide regulatory process. The Environmental Protection Agency (EPA), as the decision-making body, has largely relied on pesticide manufacturer’s self-governance associated with pesticide cancellations.
Fortunately, the prevalence of organic and biodynamic wines has increased in many wine regions throughout the world, not just in the United States. Behind this growth stand many independent producers that produce low intervention, organic wine on a small scale and with minimal additives.
Sulfides and Natural Wine
While I also believe that the use of native yeast results in wines that better reflect their vineyard’s terroir, I sometimes feel that the use of sulfites in the context of natural winemaking is often misunderstood by consumers. Sulfites, historically used in winemaking for their anti-bacterial and antioxidant properties, appear now to be the most important wine ingredient to avoid at all costs among many consumers.
Sulfides and Wine Consumers’ Health
Where does this sulfite aversion stem from and what does science say about sulfites in wine and their potential impact on health? According to WebMD, the use of sulfites ass additives in the food and beverage industry increased significantly in the 1970s and 1980s, when restaurants used sulfites to ensure that their salad bars remained looking fresh. In the years that followed, a small percentage of the population encountered severe reactions to this additive, resulting in the FDA banning the use of sulfites on fresh fruits and vegetables.
While this ban occured several decades ago, the FDA estimates that approximately one percent of the population lives with a sulfite sensitivity that can cause an adverse reaction. People impacted include individuals with sulfite-sensitive asthma and those suffering from a condition called sulfite oxidase deficiency. Sulfite oxidase is an important enzyme in the human body that breaks down ingested sulfites. The remaining ninety nine percent of the population has no problems with the ingestion of limited amounts of sulfites.
Yet adverse reactions to wine consumption, particularly red wine consumption, is often blamed on the addition of sulfites among consumers. However, if sulfites in a bottle of wine were the cause, then drining white wine should lead to even greater adverse reactions, since white wine usually has far greater amounts of this wine additive included to limit any potential oxidation in bottles.
Biogenic Amines in Wine
Research into the cause of headaches, watery eyes, and similar adverse reactions from wine consumption now seems to indicate that biogenic amines in wine might be the real culprit. Biogenic amines (BA), according to Jamie Goode, are “present in all fermented food and drink” and are “produced from amino acids via enzymatic activity in living organisms like microbes.” Histamine is the most well-known of the group of BA compounds and, per Jamie Goode “is produced when microbes remove carbon dioxide from the amino acid histidine.” Ingested in excessive levels in wine, histamine can lead to the above mentioned reactions.
Sulfites in Winemaking
From a winemaking perspective, the importance of sulfites, as an antibactial and antioxidative agent cannot be stressed enough – if delicious, high quality wines without any obvious flaws are the desired outcome. Some consumers may not know that sulfites occur naturally during fermentation and are therefore always present in all wines. The complete omission of any sulfite addition during winemaking, moreover, can lead to many wine faults in the bottled wine.
Among the most problematic faults is a mousy character. The occurrence of a mousy taint, an off-flavor reminiscent of caged mice, has dramatically increased with the rise of more and more natural wines, many produced with no added sulfites or insufficient sulfite additions prior to bottling. According to the Australian Wine Research Institute, the compounds responsible for the off-flavor have been identified as: 2-ethyletrahydropyridine, 2-acetyltetrahydopyridine and 2-acetylpyrroline and there is currently no known treatment to remove it from affected wine, except for blending it with non-impacted wines. Most lactic acid bacteria and some spoilage yeasts are capable of the production of this taint. New research has indicated that excessive exposure to oxygen may also cause the mousy taste in wine.
Complicating things further, mousy off-flavors, unlike other wine taints that could be present in unsulfured natural wine, are not perceptible as an aroma in wine. The compounds identified above only become aromatic at neutral or higher pH levels. Therefore, only swirling the affected wine in one’s mouth and mixing it with saliva, thereby raising the wine’s pH leads to the extremely unpleasant taste.
Sulfite Use in Low Intervention Winemaking
So where does one draw the line of sulfite use in the context of natural winemaking? For example, in the European Union, the sulfur dioxide limits are 100mg/L for organic red wine and 150mg/L for organic white wine, respectively. In contrast, in the United States, for wines to receive the term organic wine on the bottle label, the grapes must not only be farmed organically in an organically certified vineyard, they also must not receive any sulfur dioxide at all during the winemaking process (10mg/L from natural occurring sulfur dioxide is accepted). There does not seem to be any clear-cut answer to this question, since even the numerous organic certifying bodies in winemaking regions throughout the world require different limits.
Our Point of View
For the production of our low intervention wines, we employ the minimum effective sulfur amounts necessary. In sum, while we attempt to create minimally manipulated wines from organic vineyards, we also believe that consumers prefer to drink a delicious, high quality wine without detectable flaws.