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  • January 25, 2014
  • Light, Digestible Rieslings from the Saar and Mosel

  • by Martin Kössler

Maximin Grünhäuser Abtsberg.

Editor’s note: In July 2012, Florian Lauer brought Martin Kössler’s article to my attention and asked me to translate an edited version that focuses on Saar and Mosel wines. I finally got around to it. Before publishing it in English, I asked the wine critic David Schildknecht to take a look at a few passages that needed proofreading.

The pH value—the key to health and quality

The pH value is a measure of acidity and basicity in an aqueous solution, such as grape juice or wine. The pH scale is between 0 (very acidic) and 14 (very alkaline). Water is neutral and has a pH value of 7.

In wine, the lower the pH, the more stable and healthier is the wine. The higher the pH, then the lower the acidity, and all the more attention must be paid to the microbiology, the wholesomeness, and the stability of the wine in question.

The pH values in wine worldwide are between 2.9 and 4.0 and depend on the grape variety, growing region, and grape maturity.

On the Saar and Mosel, and especially in the case of Riesling, grape musts are ranked at the bottom of this scale. The pH values are from 2.9 to 3.1; anything higher is the exception.

In the grape, three main acids are dominant: tartaric acid, malic acid, and citric acid. In the must and wine, other acids are produced during the alcoholic fermentation and during the maturation in cask or tank. These include acetic acid, butyric acid, lactic acid, and succinic acid. Their harmonious interaction with the sugar and alcohol content gives us a good wine, plus the feeling of freshness and structure in the month. Together with the extract and concentration of the wine, true wine quality is produced.

With a low pH value, it’s not about “sour wine”! It’s about freshness, as well as a mineral and pleasant mouthfeel. When wine analyses show the acid value, then that is the absolute amount of acidity in grams per liter. But, if we want a concrete statement about the taste, then the pH, as the sum of all six major acids of the wine, is much more meaningful for the assessment of quality.

In the grape, the pH is lowest just before the onset of maturity; with more ripeness, it increases. As the aggressive malic acid is “respired” in the course of ripening, the production of tartaric acid stops, when the cellular tissue of the berry is ripe. From the sensory assessment of this balance (analysis of chewed berries and seeds), the experienced winemaker determines the time of his harvest, which can influence the character and style of his wines—if he has mastered it. The hotter a vintage or the warmer the vineyard, the more readily and profoundly the respiration of malic acid proceeds, which can lead to a relatively mild taste impression.

In the cellar, the pH is most critical to the health of the must and to the clean aroma of the fermentation, because in an acidic environment, bacteria can hardly survive. The pH is an important characteristic for its quality. More and more people report headaches after enjoying wine—especially after consumption of red wine. And even after white wine enjoyment, there are more and more people, especially women, who complain of headaches up to migraines.

One is quick to say that it’s caused by sulfur dioxide (SO2), because “the sulfur in the wine causes a headache.” “Only bad winemakers sulfur their wine”—about no other matters vinous do more rumors circulate or are more false clichés propounded than about sulfur. Alcohol is, after all, a cytotoxin. But complaints, as described above, rarely go back to alcohol alone. They cannot be imputed to the sulfur in the wine.

Since a few years now, it’s become known where the medical conditions come from, and one researches intensively into their origin and effect—they are “biogenic amines.” They are natural ingredients in many foods, especially in ripened cheese, wine, beer (especially in wheat beer), in sauerkraut, and, in high doses, in fish products, and salami. The most common food intolerance that comes from biogenic amines refers to the well-known histamine.

Someone who reacts to histamines is not allergic, but rather is exhibiting a histamine intolerance. Medical statistics have for years registered a significant increase in this specific intolerance, which, besides elevated histamine levels, is diagnosed on the basis of reduced diamine oxidase (DAO). This is a sensitive endogenous enzyme, which can be inhibited by biogenic amines, alcohol, and its degradation product acetaldehyde in its effect. The enzyme in the body causes the removal of the alcohol, the so-called alcohol dehydrogenase (ADH), competes with other enzymes for the required oxygen. In combined intake of alcohol and biogenic amines of the reduction of the alcohol is privileged and the histamine begins to accumulate in the body. Thus, the toxic effect of the alcohol is enhanced by histamine.

Climate change has led to earlier maturity with better-ripened grapes in large parts of Europe. This leads to a more rapid degradation of the malic acid in the grape and thus to higher pH values. This favors the activity of harmful bacteria, especially the “malolactic fermentation,” on behalf of lactic acid bacteria, which is standard for red wine, but is increasingly practiced, actively or passively, in white wines. Formerly, the threshold of pH 3.4 at which proliferation of these bacteria sets in was almost never reached. Today, there are hardly any red wines with lower pH values, and even many white wines lie higher. These bacteria are the main producers of harmful biogenic amines.

Digestible, low histamine wines are now found mainly in the cooler growing regions of Central Europe. One of the few remaining areas is the relatively cool Saar and Mosel region, which is guaranteed to have the worldwide lowest pH with its stony slate soil. ♦

Edited by Florian Lauer of Weingut Peter Lauer in Ayl.

Translated by Lars Carlberg. David Schildknecht—without taking a position on the merits of Kössler’s case—was kind enough to offer me selective assistance with this translation.

Photograph of Maximin Grünhäuser Abtsberg.

Martin Kössler studied engineering in material science. Over 30 years ago, he became a wine merchant from a conviction of pursuing a taste concept based on his scientific background and dealing with the question: "Why does the wine taste so?"

  • In the 19th century, there are a number of German books by various authors, especially doctors, who explain the special health benefits of Mosel wine. I’d like to write an article about this at some point. All of them highlighted Mosel wine’s pronounced acidity and lightness.

    As for the photo, I chose a shot of Maxmin Grünhäuser Abtsberg, because Martin and Florian’s article only mentions the Saar and Mosel. They assume, of course, that you know that the Ruwer, like the Saar, is a subregion of the Mosel. This was no different from before the appellation Mosel-Saar-Ruwer in 1909, which only became officially required on labels in 1936. It was later shortened back to Mosel in 2007. (In the 19th century, the Saar was often mentioned as a distinct part of the Mosel, whereas the Ruwer tended to be grouped under “Mosel.”)

    Martin is a fan of Grünhaus, but tends to favor Herrenberg more than Abtsberg.

    • Andrew Bair says:

      Thank you both for the article, Martin and Lars. Chemistry was never my strongest subject in school, so I appreciate the well-written, ably translated article (thanks too, David).

      • Andrew: You’re welcome. Actually, you should thank Florian Lauer, who rewrote Martin’s essay with a focus on Saar and Mosel wine. Chemistry wasn’t my strongest subject either. I translated the article; David helped me with a few difficult passages.

        By the way, I came across this article on Palate Press: “Not tonight, I have a wine headache…” It supports Kössler’s point that biogenic amines and alcohol are what cause most headaches from wine.

  • Kyle Wilson says:

    Generally speaking, does a lower pH in a wine correspond with a lower pH in the soil? I understand their are a number of contributors to the final result of a wines pH: exposition, slope, climate, elevation etc. But is there an underlining parallel that exists between these low pH soils and low pH wines?

    • On my last day of viticultural school in Bernkastel-Kues, I asked one of my teachers if there was a direct correlation between a lower pH in the soil and a lower pH in the wine. He doesn’t believe that there is one. In his opinion, the more important factor is the climate. He also says that the term “mineral” to describe Mosel Riesling from slate is a euphemism for “sour.” He claims that a wine from a chalky soil is more minerally than one from slate.

      Johannes Weber of Hofgut Falkenstein says that other factors also play a role in raising the pH value of a wine, such as leaf removal and skin contact.

      Johannes had pH levels below 2.9 (including wines at 2.7 and 2.6) in the 2016 vintage. With such a low pH (3 or under), sulfur dioxide is more effective and lower amounts can be used in the wine.

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