Where does Riesling come from? Noble Rot and Fun Facts about Riesling.

Where does Riesling Come From?
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. Most likely, the genetic differences between white and red Riesling are minuscule, as is the case for the difference between Pinot noir and Pinot gris.

Image; tight riesling grape bunches
NOBLE ROT aka BOTRYTIS
A bunch of Riesling grapes after the onset of noble rot. The difference in colour between affected and unaffected grapes is clearly visible.
The most expensive winesmade from Riesling are late harvest dessertwines, produced by letting the grapes hang on the vines well past normalpicking time. Through evaporation caused by the fungus Botrytiscinerea ("noble rot") or by freezing, as in the case of ice wine (inGerman, Eiswein),water is removed and the resulting wine offers richer layers on the palate.These concentrated wines have more sugar (in extremecases hundreds of grams per litre), more acid (to give balance to all thesugar), more flavour, and more complexity. These elements combine to make wineswhich are amongst the most long lived of all white wines. The beneficial use of"noble rot" was discovered in the late 18th century at Schloss Johannisberg. Permission from the Abbey of Fulda (which owned the vineyard) tostart picking the grapes arrived too late and the grapes had begun to rot; yetit turned out that the wine made from them was still of excellent quality

FUN FACTS ABOUT RIESLING
In 1977 Galafrey Wines Planted Riesling #summerofriesling
In Galafrey Wines won their first Internal Throphy for their 1991 Riesling #summerofriesling
FACT Riesling is a white grape variety which originated in the Rhine region of Germany. #summerofriesling
Riesling is an aromatic grape variety displaying flowery, almost perfumed, aromas as well as high acidity. #summerofriesling
Riesling is used to make dry, semi-sweet, sweet and sparkling white wines. . #summerofriesling
Riesling wines are usually varietally pure and are seldom oaked. . #summerofriesling
Riesling is a variety which is highly "terroir-expressive", meaning that the character of Riesling wines is clearly influenced by the wine's place of origin. . #summerofriesling
Riesling is most commonly grown in colder regions and locations . #summerofriesling
Riesling wines are often consumed when young, However, Riesling's naturally high acidity and range of flavours make it suitable for extended aging. #summerofriesling
Riesling make a fruity and aromatic wine which 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 #summerofriesling
high quality dry or off-dry Riesling wine is also known to have not just survived but also been enjoyable at an age exceeding 100 years #summerofriesling
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. #summerofriesling
Riesling was the most planted white grape in Australia until the early 1990s when Chardonnay greatly increased in popularity. #summerofriesling
Riesling is also being grown with increasing popularity in the Western Australian regions Albany, Mount Barker, Frankland River and Porongorup. #summerofriesling
Australian Rieslings are noted for their oily texture and citrus fruit flavours in their youth and a smooth balance of freshness and acid as they age #summerofriesling
The botrytized Rieslings have immense levels of flavour concentrations that have been favorably compared to lemon marmalade. #summerofriesling
It is common for Australian Rieslings to be fermented at low temperatures in stainless steel tanks with no oxidation of the wine and followed by earlier bottling. #summerofriesling
Did you know-A very rare version of Riesling which has recently received more attention is Red Riesling (Roter Riesling) #summerofriesling
late 19th century German horticulturalists develop new Riesling hybrids that would create a more flexible, that could still retain some of the elegant characteristics of Riesling. #summerofriesling
The most notable is the Muller thurgau in 1882, which is a cross of Riesling and Madeleine Royale (although long believed to be Riesling x Silvaner) #summerofriesling

Petroleum notes in aged Riesling
With time, Riesling wines tend to acquire a petrol note( petrol in French) which is sometimes described with associations 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 aromas of mature Riesling, and the preference for 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. 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 (TDN), 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
These factors are usually also considered to contribute to high quality Riesling wines, so the petrol note is in fact more likely to develop in top wines than in simpler wines made from high-yielding vineyards, especially those from the New World, where irrigation is common.