Vitrified Fuel Ash
Vitrified Fuel Ash and the Norse Fish Curing Industry (12th century AD) in Viking Orkney, Scotland
The potential association of vitrified fuel ash (VFA) with the smoking of fish and/or the boiling of cod liver for cod liver oil production, in the late Norse period in Viking Orkney, was the subject of this joint investigation with the University of York’s Archaeology Department. The implication is that VFA was formed in a hearth, in reducing or oxygen-starved environments.
Making red herring: the interior of a smoke house (Samuel 1918. The Herring: its effect on history of Britain, London).
Red herring referred to as smoked herrings, to distinguish them from the white ones, which were simply air dried.
Parallels have been drawn with VFA from a hearth at Neolithic Skara Brae as well as a Bronze Age cremation site at Crantit, both in Orkney. Although the Norse fish smoking industry and BA funerary cremation rituals have little in common other than the fact that both practices took place in Orkney, it is suggested that they are both the product of slow burning of seaweed under an oxygen deficient environment. (see cramp).
SEM image of vitrified fuel ash from a midden deposit of Late Norse date, Orkney.