Non-Vintage Brut is the most important category of Champagne. The vast bulk of Champagne is Non-Vintage and the healthy sales of this category are what keeps the Euros flowing in the region. A typical Non-Vintage cuvée will be composed of wine from two of the most recent vintages blended together, with a very small amount of older vintages. The demanding task of a champagne blender is to keep a typical house style by blending many different batches of wine. Quality does vary, at least from year to year if not batch to batch. A succession of good vintages will result in great Non-Vintage champagne with inverse consequences for a run of lesser years.
At the bottling stage Champagne is nearly always sweetened by the addition of a small sweetened dose of wine, called the dosage. The vast bulk of Champagne (including all Vintage releases) is of the "Brut" level of dryness: Dry to the palate though very lightly sweetened. The exact level of dryness of a brut style will vary from producer to producer, but is generally between 0 and 1.2% residual sugar.