Riesling
Riesling is a white grape variety that originated in the Rhine region. Riesling is an aromatic grape variety displaying flowery, almost perfumed, aromas as well as high acidity. It is used to make dry, semi-sweet, sweet, and sparkling white wines. Riesling wines are usually varietally pure and are seldom oaked., Riesling was estimated to be the world's 20th most grown variety at , but in terms of importance for quality wines, it is usually included in the "top three" white wine varieties together with Chardonnay and Sauvignon blanc. Riesling is a variety that is highly "terroir-expressive", meaning that the character of Riesling wines is greatly influenced by the wine's place of origin.
In cooler regions, such as the Mosel in Germany, Riesling wines often display apple and tree fruit notes with pronounced acidity that is sometimes balanced by residual sugar. As a late-ripening variety, Riesling can develop citrus and peach notes in warmer areas such as the Palatinate, Alsace, and parts of Austria. In Australia, Riesling is often noted for a characteristic lime note that tends to emerge in examples from the Clare Valley and Eden Valley in South Australia.
Riesling's naturally high acidity and pronounced fruit flavors give wines made from the grape exceptional aging potential, with well-made examples from favorable vintages often developing smokey, honey notes, and aged German Rieslings, in particular, taking on a "petrol" character, as a result of the development of the compound TDN.
In 2015, Riesling was the most grown variety in Germany with 23.0% and, and in the French region of Alsace with 21.9% and. In Germany, the variety is particularly widely planted in the Palatinate, Rheinhessen, Mosel, Rheingau, Nahe, and Baden.
There are also significant plantings of Riesling in Austria, Slovenia, Serbia, Czech Republic, Slovakia, Luxembourg, northern Italy, Australia, New Zealand, Canada, South Africa, China, Crimea, and the United States.
History
Riesling has a long history, and there are several written references to the variety dating from the 15th century, although with varying orthography. The earliest of these references dates from March 13, 1435, when the storage inventory of Count John IV of Katzenelnbogen in Rüsselsheim lists "22 ß umb seczreben Rießlingen in die wingarten". The spelling Rießlingen is repeated in many other documents of the time. The modern spelling Riesling was first documented in 1552 when it was mentioned in Hieronymus Bock's Latin herbal.A map of Kintzheim in Alsace from 1348 contains the text zu dem Russelinge, but it is not certain that this reference is to the grape variety. However, in 1477, Riesling was documented in Alsace under the spelling Rissling. In Wachau in Austria, there is a small stream and a small vineyard both called Ritzling, which are claimed locally to have given Riesling its name. However, there seems to be no documentary evidence to back this up, so this claim is not widely believed to be correct.
Parentage
Earlier, Riesling was sometimes claimed to have originated from wild vines of the Rhine region, without much support to back up that claim. More recently, DNA fingerprinting by Ferdinand Regner indicated that one parent of Riesling is Gouais blanc, known to the Germans as Weißer Heunisch, a variety that, while rare today, was widely grown by the French and German peasantry of the Middle Ages. The other parent is a cross between a wild vine and Traminer. It is presumed that the Riesling was born somewhere in the valley of the Rhine, since both Heunisch and Traminer have a long documented history in Germany, but with parents from either side of the Adriatic the cross could have happened anywhere on the way.It has also been suggested, but not proved, that the [|red-skinned version] of Riesling is the forerunner of the common, "white" Riesling. The genetic differences between white and red Riesling are minuscule, as is also the case between Pinot noir and Pinot gris.
Longevity
Riesling wines are often consumed when young, when they make a fruity and aromatic wine that may have aromas of green or other apples, grapefruit, peach, gooseberry, honey, rose blossom or cut green grass, and usually a crisp taste due to the high acidity. However, Riesling's naturally high acidity and range of flavours make it suitable for extended aging. International wine expert Michael Broadbent rates aged German Rieslings, some hundreds of years old, highly. Sweet Riesling wines, such as German Trockenbeerenauslese, are especially suited for cellaring since the high sugar content provides for additional preservation. However, high-quality dry or off-dry Riesling wine is also known not just to have survived but also to have been enjoyable at an age exceeding 100 years.The Ratskeller of the townhall of Bremen, Germany, stores 650+ German wines, including Riesling-based wines, often in barrel and back to the 1653 vintage.
More common aging periods for Riesling wines would be 5–15 years for dry, 10–20 years for semi-sweet and 10–30+ for sweet versions.
Petroleum notes in aged Riesling wines
On release, certain Riesling wines reveal a striking petrol note that is sometimes described with comparisons to kerosene, lubricant, or rubber. While an integral part of the aroma profile of mature Riesling and sought after by many experienced drinkers, it may be off-putting to those unaccustomed to it, and those who primarily seek young and fruity aromas in their wine. The negative attitude to petrol aromas in young Riesling, and the preference for fruitier young wines of this variety, seem more common in Germany than in Alsace or on the export market, and some German producers, especially the volume-oriented ones, have even gone so far as to consider the petrol notes a defect which they try to avoid, even at the cost of producing wines that are less suited to extended cellar aging. In that vein, the German Wine Institute has gone so far as to omit the mentioning of "petrol" as a possible aroma on their German-language Wine Aroma Wheel, which is supposed to be specially adapted to German wines, and despite the fact that professor Ann C. Noble had included petrol in her original version of the wheel.The petrol note is considered to be caused by the compound 1,1,6-trimethyl-1,2-dihydronaphthalene, which during the aging process is created from carotenoid precursors 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, i.e., low yields and late harvest
- High sun exposure
- Water stress, which is most likely in regions which do not practice irrigation, and there primarily in certain dry vineyard sites in hot and dry years
- High acid content
Noble rot
The most expensive wines made from Riesling are late harvest dessert wines, produced by letting the grapes hang on the vines well past normal picking time. Through evaporation caused by the fungus Botrytis cinerea or by freezing and pressing, water is removed and the resulting ultra concentrated juice is used to make the sweet wines. These wines are felt to offer richer layers on the palate, and have more sugar, more acid, more flavour, and more complexity. These elements combine to make wines that are amongst the most long lived of all white wines. The beneficial use of "noble rot" in Riesling grapes was discovered in the late 18th century at Schloss Johannisberg. Permission from the Abbey of Fulda to start picking Riesling grapes arrived too late and the grapes had begun to rot; yet it turned out that the wine made from them was still of excellent quality.Noble rot is employed in many viticultural areas, including the Clare, Barossa, and Eden Valleys in South Australia, and in the southern growing region of Tasmania, though none are as renowned as those from Germany.
Production regions
Riesling is considered one of the grape varieties that best expresses the terroir of the place where it is grown. It is particularly well suited for slate and sandy clay soil.Germany
Riesling is Germany's leading grape variety, with the country accounting for around 40% of global production. German Riesling is known for its characteristic “transparency” in flavour and presentation of terroir, as well as its balance between fruit and mineral flavours. In Germany, Riesling typically ripens between late September and late November, with late harvest grapes sometimes picked as late as January.Traditionally, German Riesling is rarely blended with other varieties and usually fermented in neutral steel tanks or old oak barrels. However, some vintners, particularly from the Palatinate and Baden, also use new oak aging. Warmer growing conditions in those regions tend to produce fuller-bodied wines with higher alcohol levels that can better accommodate new oak influence.
When young, German Rieslings often show distinct fruit and mineral flavours, while with age they are considered to integrate and develop greater harmony.
Before the advent of temperature-controlled fermentation, winter cold in northern regions often halted fermentation, leaving wines with natural sugars and relatively low alcohol. In the Mosel region, these wines would be bottled in tall, tapered, green hock bottles, while in the Rhine region similar bottles were used in brown glass.
Harvest sugar levels are central to production in Germany, where the prädikat system classifies wines by must weight and sweetness. Equally important is the balance of acidity between the green tasting malic acid and the more citrus tasting tartaric acid. In cool years, some growers delay harvest into November in pursuit of higher ripeness and more citric taste.
Riesling is the preferred grape variety in the production of Deutscher Sekt, Germany's traditional sparkling wine. German Riesling covers a vast array of tastes from sweet to off-dry to fully dry with late harvest examples capable of producing rich dessert wines at the beerenauslese and trockenbeerenauslese levels.