title_body: When some one uses "sweet" to describe Blanc de Noir Brut Champagne, what does it really mean?
upvoted_answer: When some one uses “sweet” to describe Blanc de Noir Brut Champagne, what does it really mean?
  Sweetness is a way to express the amount of residual sugars to alcohol levels in a wine or champagne.
  
  Rough rules of thumb say if a wine's alcohol content is 10% or less it will have sweet characteristics.  Wines that are even lower (especially down around 8 or 9 percent) will definitely be sweet. Wines in the 11% to 12.5% ABV range are considered 'off-dry' meaning that there is some notable residual sugar.  If it’s 12.5 percent or higher, the wine will will be 'dry' and have little to no perceptible sweetness.
  Most wines under 10% ABV will be sweet. Typically, wines such as German Riesling and Italian Moscato fall in this category. Wines in the range of 10.5% to 12.5% include Riesling's from Austria, Australia and the U.S., Sauvignon Blanc, and Pinot Grigio (a.k.a. Pinot Gris).  Then, in the 12.5% to 15.5% range you find Chardonnay, Pinot Noir, Cabernet Sauvignon, Malbec, Sangiovese, Syrah, Grenache and Zinfandel.
  But, as previously pointed out, a grape that starts with low sugar levels, and ferments to the point where all the sugar is consumed by the yeast, will result in a wine with lower alcohol levels and little to no residual sugar. So, this is why alcohol levels are not a dependable way of determining a wine's sweetness.
  So, while there’s definitely a loose relationship between a wine’s residual sugar and its alcohol level, it’s not a simple relationship.  But you can use the percent alcohol printed on the label as a first indication. - Is There a Relationship Between a Wine's Sweetness and Its Alcohol Level?