Keuper | A soil type described by Tom Stevenson (2011), a term ‘often used when discussing wines in Alsace, Keuper is a stratigraphic name for the Upper Triassic period and can mean marl (varicoloured, saliferous grey, or gypsiferous grey) or limestone (ammonoid).’ It is supposed to have good retention of solar heat.

Bibliography

Tom Stevenson (2011) The Sotheby’s Wine Encyclopedia 5th Edition by Tom Stevenson (Dorling Kindersley, 2011), p.17-19.