The most obvious difference is butterfat: By law, American butter must contain at least 80 percent, while the minimum for French butter is 82 percent (unless it is demi-sel, or salted butter, which can check in at 80 percent and include up to 2 percent salt). Two percentage points may sound measly, but since butterfat affects butter’s flavor, texture and workability, every little bit counts.
Enjoyed reading about Beurre d’Echire, which enjoys an appellation (awarded to Deux-Sevres butter) indicating that the quality of the butter is marked by the quality of the milk, with its provenance in cows feeding on land within 19 miles of the small village of Echire, between Poitiers and La Rochelle on the Atlantic coast. (NYT per above)
