Starbucks has a lot going for it. It’s on every corner, it always tastes the same, and it’s made you aware of all the ways your name could be misspelled. But your caramel macchiato probably doesn’t transport you to farms in Brazil or Indonesia. Whereas, get a single-origin coffee from some place with elaborate pour-overs, and you’ll feel quite a bit different.
You can think of Champagne in the same way. Big producers like Moet & Chandon and Veuve Clicquot are kind of like Starbucks. They buy grapes from thousands of farmers, blend them together to create a consistent house style, and distribute their wines pretty much everywhere. A small fraction of farmers, though, don’t sell their grapes to the big houses. Instead, they use them to produce their own wines. They make what's called grower Champagne.
Grower-producers farm the land, harvest the fruit, and make the wine. Since the grapes come from one farm rather than from vineyards across Champagne, these wines are the best illustrations of the region’s unique terroir. The same grower-producer might release two wines made with the same grape variety from the same subregion, and they could taste totally distinct. While the big Champagne houses do everything they can to eliminate this kind of variability, grower-producers embrace it, creating Champagne that reflects exactly where it comes from.