Located in Epfig, in the Lower-Rhine, the Domaine Ostertag ("Easter Day") has raised itself to the top of the hierarchy of Alsace properties in just two generations. Adolphe Ostertag created the Domaine in 1966. His son André took over in 1980, helped by his sister Annie. There are 15 hectares of vines, consisting of a hundred plots spread over five different terroirs. André Ostertag is in the habit of talking of the 80 gardens that he tends.
Trained in Burgundy, André has made quality his priority. Controlled yields, careful management of the vines, meticulous vinification, and ageing partially in barrels (for the Pinot Gris). In 1997, he converted the vineyard to organic farming (with AB certification) and then to biodynamic methods (without certification). Riesling, of which André Ostertag is a big fan, accounts for nearly 50% of the property's vines. The other varieties, in decreasing proportions, are Gewurztraminer, Pinot Gris, Sylvaner, Pinot Noir and Muscat. Different combinations of terroirs, grape varieties and levels of ripeness enable the Domaine to produce about twenty cuvées each year. André Ostertag classifies them in three main families: fruit wines (expressing the variety and grape flavours); stone wines (expressing the terroir); and vins de temps (which involve both meanings of the French word "temps" i.e. "weather" and "time", resulting in late ripening or noble rot).

Clos Mathis owes its name to the talented Hubert Mathias who supported the Ostertag family for 20 years, from 1997 to 2017. In 1997, Hubert wished to make his way in the world of biodynamics with the Ostertags and began working alongside them. Owners of this stone-enclosed clos, it is with much passion that André Ostertag and Hubert Mathis craft this cuvée that has been highly esteemed since the Middle Ages. The vineyard is located at the foot of 3 châteaux in the commune of Ribeauvillé. The soil is made up of granite and gneiss, with the vines exposed to the south-east. This cuvée has the air of a fine, regional Riesling. Its glistening, yellow hue and its floral nose will be emphasised when decanted half an hour before serving. This wine can be kept for almost 20 years in a good cellar.