It’s not about the brunette, whom Lyu Hanabusa shot for Mark Williamson’s Willi’s Wine Bar vintage 1993 poster, but rather an observation about skin contact (or, pre-fermentation maceration) for Mosel Riesling. Admittedly, this is another geek posting about a technique (Maischestandzeit) that has so many facets and will only be covered here on a superficial level, but deserves a closer look.
It’s common practice in the region, especially for sweet wines, with botrytis-affected grape bunches, to be pressed without any maceration. Many producers in their sixties or seventies always did it this way. Some critics argue that skin contact (click on our glossary and scroll down for the definition) has become à la mode on the Mosel. And surely, they’re right that some wine-makers are following a trend here. Yet, macerating Mosel Riesling before pressing is a traditional method of handling the grapes before fermentation begins in order to extract from the grape skins aromas, phenols, and potassium, the latter helping to buffer acidity. Obviously, many wine-makers, especially those focusing on high-residual-sugar wines, handle their grapes differently, that is but putting them directly in the press with or without crushing the grapes beforehand, and if crushed, then without maceration.
Looking at some old archive photos of the Mosel Valley in Karl-Josef Gilles’s Das Moseltal Zwischen Koblenz und Trier 1920-1950, crushers are shown placed on top of open-wooden vats that were carried on horse- or ox-drawn wagons at the foot of steep hillside vineyards and then the crushed grapes were brought back to the winery for pressing. The grapes often macerated an entire day or even longer on their skins, pips, and juice. The winegrowers would then fork the grapes into a wooden-basket press. These old-style presses gave fine, clear juice, which was further exposed to air before running down into the barrel cellar below. Today’s pre-fermentation maceration with must oxidation, as practiced by Clemens Busch, reproduces these time-honored methods. Certainly, in the old days some winegrowers crushed and macerated purely as a means to get more grapes into the wooden vats and to avoid having to go back to the winery. Others consciously sought out to extract from the skins more aromas and phenols.
Just as skin contact is used to increase phenolics, whole-bunch pressing has become popular among producers in other regions to decrease them. Both Olivier Zind-Humbrecht and Jean-Marie Deiss told us on our visit to Alsace last summer that they prefer to handle their grapes as gently as possible by direct (pneumatic) pressing, no crushing or macerating beforehand. This probably has some to do with the climate being warmer and the wines naturally more opulent.
At Markus Molitor and Van Volxem (two large, flagship estates on the Mosel and Saar, respectively) extended hang times and skin contact are preferred and both have invested in modern Swiss-made, stainless-steel basket presses. Van Volxem also likes to offset any bitterness resulting from phenols extracted during prolonged skin contact by micro-oxygenating the must, but not the wine. The results at both estates speak for themselves.
Ulli Stein explained that maceration is a complex theme that needs to take into account different factors such as wine style, grape variety, climate, health of the grapes, ripeness levels, acidity, and so on. Generally speaking, he feels that skin contact on the Mosel increases the complexity of the later wine, but decreases its elegance. It’s a fine balancing act and only pertains to healthy, high-quality grapes. Less healthy grapes, in his opinion, should either be crushed and pressed or direct-pressed. For healthy grapes to be macerated, he considers three main factors: grape acidity and quality as well as the sought-after wine style.
In a high-acid vintage, and for progressively higher ripeness levels, he does longer macerations. For example, his 2008 Palmberg Spätlese trocken was 14 hours on the skins; whereas, the less ripe 2008 Himmelreicht Kabinett trocken only 4 hours. And the opposite is true for riper years and lower quality wines, i.e., less maceration. He also feels it’s better to macerate at cooler temperatures to avoid excessive extraction of phenols. As a rough guideline, he points out that one hour of maceration reduces acidity by 0.1 grams per liter and increases the danger of the wine later going through malolactic fermentation either during or after the end of the alcoholic fermentation. For ripe grapes, he recommends macerating with the stems. Otherwise, it makes sense to destem. In Alsace or Chablis, he feels the wines already have enough opulence, but less acidity and delicacy. That’s why they often avoid doing skin contact, instead preferring more elegance at the cost of fullness, which is in their wines already plentiful to begin with. They don’t need extra oxidation measures to reduce it.
Last November I tasted and compared Weingut Günther Steinmetz’s 2008 Riesling (a special Triage Wines’ bottling) and 2008 Mülheimer Sonnenlay Riesling Spätlese trocken “Alte Reben.” Although the latter showed more grip and substance from “old vines,” the extended 36-hour skin contact didn’t make it—as some might presume—rich, oxidized, or overly extracted. And both held up beautifully over several days in the fridge and are excellent examples of naturally low-alcohol, dry-tasting Middle Mosel Riesling. Even if the grapes for the 2008 Riesling were crushed and then direct pressed without skin contact, it still has a good depth of flavor and clocks in at a mere 10% alcohol by volume. The old-vine Spätlese is only a degree higher, at 11% alcohol, and also has a light color and bright acidity despite the long skin contact.
Why does Stefan Steinmetz then choose to do skin contact on the one wine, but not for the other? For his 2008 Estate Riesling (Triage Wines), the grape bunches were harvested en bloc and included grapes that were affected with botrytis. He wants to avoid macerating these grapes, which could give off-flavors. His old-vine Spätlese from the Sonnenlay vineyard consists, on the other hand, only of healthy and ripe grapes, because the botrytis-affected bunches were harvested beforehand. In other words, there was a pre-selection in this site.
Stefan has several reasons for doing skin contact for his top dry-tasting wines: (1) reducing acidity with higher mineral components; (2) lessening the danger of atypical aging taint by extracting Caffeic acidity; (3) increasing the aromatics; (4) extracting more flavor, glaze (schmelz), and volume; (5) getting the ripe tannins; and (6) following a tradition on the Mosel, because the pH levels are low, i.e., the wines have higher acidity and more resistance to microbiological spoilage.
Direct-pressed grapes on the Mosel will rarely result in a wine having the same structure than ones that have had some maceration. Many producers avoid pre-fermentation maceration, even for dry Riesling. Erich Weber at Hofgut Falkenstein exclusively ferments with wild yeasts in Fuder, and the wines, mostly dry, are slowly squeezed without crushing in a spindle press. Even though he’s less in favor of skin contact, the wines are gently pressed for three to five hours that includes some maceration. With his richer soils and crisp, taut style, he’s less keen on breadth in his wines.
At Weingut Peter Lauer on the Saar, Florian Lauer has, as most producers, a pneumatic press. His is an Italian-made Defrancheschi, and he likes to do whole-bunch pressing, as well, with some maceration inside the press, depending on the wine in question. He also treads the harvested grapes before pressing. Ulli Stein, whose style is for dry, light-bodied Mosel Riesling, does after gentle crushing a cool maceration before pneumatic pressing. In a throwback style, Martin Müllen, in Traben-Trarbach, likes to do a gentle crushing—without destalking—followed by putting the grapes into an old basket press and then into barrels. Each winegrower has their own approach.
As with all aspects of wine-growing and -making, it depends on the producer and the style of wine to be made. Many factors play a role in determining if it makes sense to do skin contact and what the end results will be.