Riesling Rules Book

Riesling is a very hardy grape variety that thrives in cool climates and relatively poor soils. The grape requires a long growing season to ripen properly. In warmer climates, Riesling can lose its acid backbone, which is a main characteristic that helps make the wine bright, complex and balanced. Riesling wines generally do not respond well to newish, small oak barrels, preferring to be vinified and aged in stainless steel or larger neutral wood containers.

Riesling is a very aromatic and expressive grape variety, offering impressions of fresh flowers like honeysuckle and jasmine. Riesling’s aromas and flavors are often compared to orchard fruits like apple, peach, apricot (the apricot aroma is often a characteristic of the wonderful “noble rot”) and even the tropical-scented lychee or guava. Riesling wines are often described as tasting clean, racy and bright. Aged Riesling can take on more complex aromas which, in high quality wines, can include an aromatic expression of petrol, diesel or linalool.

Riesling’s compact bunches and small berries make it prone to rot (some of which is beneficial and necessary to make certain styles of wine). Noble rot (Botrytis cinerea) dehydrates ripe grapes, concentrating them to a point where they are capable of producing very memorable, rich, long-lived dessert wines.

Riesling is an extremely versatile grape capable of producing world-class wines in all styles from bone dry to sparkling to intensely sweet. No other grape is able to express itself through this full stylistic spectrum with such grace and competence. Riesling is able to do so both because of its high natural acidity and potential to develop high sugar levels.

For wine, acidity is a great ally. Acidity is a natural preservative, allowing wines to age and develop more gracefully (and longer) in the bottle, while providing the structure or backbone around which the wine is built. Acidity also provides a counterpoint to sweetness and has a balancing effect upon wines that are made with measurable residual sugar.

When we drink wine, acidity provides our palates with a sensation of freshness, brightness and liveliness. The acidity cleanses our palate when consuming food, helping to keep us interested in both what we are eating and drinking. Wines without sufficient acidity can appear dull, boring or flat, or as if nothing is there to hold them together (lacking balance and harmony).

There’s a Riesling to fit any situation and circumstance – to pair with cuisine as diverse as the lightest seafood and salads to the richest meat dishes and complex sauces to even sweet desserts. The fun challenge is discovering the right Riesling for a particular food and occasion.

Several factors affect the impression of a Riesling wine’s sweetness on the palate. As residual sugar increases, the impression of sweetness increases. The sweetness from the sugar interacts with:

The acidity (malic and tartaric acids) and the level of dissolved carbon dioxide, which offers a sense of freshness

The phenolic content, which offers astringency and body

The ethanol content, which brings a feeling of weight, warmth and dryness on the finish

The pH, which accentuates the expression of the acids and reduces the sensation of sweetness as it goes down

For example, a Riesling with 1.5% (grams/liter) residual sugar can appear either dry or sweet. If the wine is 12.5% alcohol with a pH level below 3.0 and an acid level above 9 g/L, the wine will appear to be quite dry. If the wine is 10% alcohol with a pH level of 3.3 and an acid level around 6 g/L, the wine will seem relatively sweet.

The most expensive and complex wines made from Riesling are high-sugar dessert wines. To craft these wines, the first technique is to concentrate the grapes through the evaporation of water caused by the fungus Botrytis cinerea or “noble rot.” The second technique is to concentrate the grapes allowing them to freeze, as in the case of ice wine (in German, Eiswein). These concentrated wines have more sugar (in extreme cases, several hundred grams per liter), more acid (to give balance to all the sugar), more flavors and more complexity.

The resulting wines are among the most age-worthy of all wines. The beneficial use of “noble rot” was discovered in the late 18th century at Schloss Johannisberg in the Benedictine Abbey of Fulda. At the abbey, they once started picking rather later than had been their custom and the grapes had begun to rot. It turned out that the wine made from these grapes was of exceptional quality and greatly exceeded expectations. The first Eiswein is rumored to have been made in 1794 in Franken.

Despite Riesling’s many wondrous attributes, it is sadly still a greatly misunderstood wine. Many New World wine lovers have the misconception that all Rieslings are sweet, while others simply state that they have an unequivocal aversion to Riesling. There are some explanations for these negative impressions.

Many memories linger from the 1970s and 1980s when U.S. consumers’ experience with German wines was dominated by mediocre, semisweet Liebfraumilch, represented by certain mass-produced and heavily advertised brands. These wines were widely distributed (U.S. volume in the mid-1980s hit 1.5-million cases… nearly unparalleled case totals for that era). The truth is that the wines contained little, if any, Riesling and were composed primarily of high yielding, less distinctive grapes like Sylvaner and Müller-Thurgau. Apart from tarnishing the name of the noblest white grape of them all, the wines conditioned many to expect a very circumscribed experience from German wine, and by extension, Riesling – one of relative simplicity and sweetness, lacking balance and a true sense of place or terroir.

Ironically it can be argued that of all white grape varieties, it is Riesling which most purely expresses the qualities of balance and terroir. A tragic consequence of the great misconception that had grown up around Riesling – essentially, guilt by association – is that many true connoisseurs and lovers and admirers of terroir still are unaware of Riesling’s great potential to express terroir and to age magnificently.

It’s also important to remember that while, yes, there have been wretchedly sweet Rieslings, these wines are generally not wretched because they are sweet, but rather because their sweetness is not balanced by a correspondingly high degree of acidity. Since Riesling naturally possesses an extremely high level of acidity, especially those examples grown in the coolest climes, a skilled winemaker can allow for the most felicitous and harmonic sugar/acid balance.

What is this minerality thing? Most rocks when ground to smithereens do not have much taste or flavor. Nevertheless, few would dispute that Rieslings grown from differing soil profiles often exhibit extremely different organoleptic characteristics. Because of the lack of interference of other elements – malolactic fermentation, oak, elevated alcohol levels, etc. – one can very easily learn to distinguish the flavor of Riesling grown on schist as compared to slate or limestone. Because Rieslings are grown in such minimal soil on the steep slopes of the greatest vineyards in Germany and Austria, they must derive their moisture from exploring the fissures of the fractured subsoil, mining for water. Vines grown under these extreme conditions, as well as older vineyards (with the deepest roots) will tend to exhibit the highest degree of minerality. It is also believed by some that the putative elevated mineral content of Riesling is implicated in the wine’s prodigious longevity.

The petrol note is considered to be caused by the compound 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN), which during the aging process is created from carotenoid precursors (terpenes) by acid hydrolysis. The initial concentration of precursors in the wine determines the wine’s potential to develop TDN and petrol notes over time. From what is known of the production of carotenoids in grapes, factors that are likely to increase the TDN potential are:

 
• Ripe grapes (accentuated by low yields and/or late harvest)
• High light exposure
• Water stress, which is most likely in regions that don’t practice irrigation. This primarily occurs in dry vineyard sites during warm and low-rain years
• Warm soils (gravel, etc.)

These factors are usually also considered to contribute to high-quality Riesling wines. The petrol note is, in fact, more likely to develop in top Riesling wines than in simpler wines made from high-yielding vineyards. Riesling grown in warmer climates, such as Alsace, will tend to exhibit the petrol character earlier in their post-bottling development. A discreet amount of petrol aromatics is a great enhancer, too much can be a bit of a turn-off.

It’s often a surprise that some white wines have greater ageability than many red wines. Riesling wines have, for the most part, great aging potential. The aging potential comes from the naturally low pH (and high acidity) of Riesling wines as well as from Riesling’s mineral aspect, or at least, that is what is theorized. The aging potential is accentuated as the sugar level increases. Some dessert-style Rieslings have the longest ageability of any wines, reaching up to 100 years. Proper storage (50-55°F) will help to age the wine gracefully and to the longest extent.

In fact, the town hall of Bremen, Germany, stores various German wines, including Riesling wines, in barrel back to the 1653 vintage.

Few would dispute that Riesling does not like new oak; new wood generally stomps all over Riesling’s delicate flavors. The variety also does not favor malolactic fermentation, which has the lovely floral characteristics that make Riesling the special grape that it is. Finally, Riesling generally prefers not to be blended with other grape varieties.

Riesling, because of its purity, shows cork taint arguably more than any other varietal wine. As early as 1976, Australian producer Pewsey Vale bottled Riesling under screwcap. Now most of the Australian Rieslings – like many US and German Rieslings – are bottled under screwcap, a guarantee of freshness and purity.