The obvious difference between the dry and the sweet Riesling is obviously the residual sugar content which is about 10 times higher in the sweet Riesling. But that is not all and below is a list of what makes those two wines very different beyond the obvious:
– The sweet Riesling grapes are picked about two to three weeks before the Dry Riesling grapes so the flavors are much greener fruit for the sweet (pear, apple) than for the dry (apricot, tropical). The acid structure (providing balance to the sugar) and phenolic content (providing structure to the wine) is also different and sweet Riesling wines tend to be much tarter and less phenolic.
– The Dry Rieslings are left on fine fermentation lees for at least six months giving the wine extra body and added yeasty flavor (think of the smell of a great slice of bread). The sweet does not see any lees aging.
-The combination of the early harvest picking date and the natural residual sugar in the sweet leads to low alcohol wines (about 9%) versus the dry (usually about 12.5%).
– The amount of natural carbon dioxide from fermentation is different for the sweet (higher) than the dry (lower) due to the length of aging. This works well because the early bottling sweet, having a higher sugar content, enjoys more carbon dioxide (usually 25% more) to balance the wine. The Dry has much lower carbon dioxide content.
That reminds me that I wanted to post my tasting sheet for Rieslings so you can see how we rate and sort wines at Pacific Rim.