Artists used leftovers from brewing to paint

NEW YORK — Danish painters in the 19th century may have turned to an unusual source for some of their supplies: breweries.

Researchers examined paintings from the Danish Golden Age and found traces of yeast and grains. That suggests painters were turning to byproducts from local breweries to prepare canvases, they reported Wednesday in the journal Science Advances.

Study author Cecil Krarup Andersen said they went into the project looking for glue made from animals.

“Then, by surprise, we found something completely different,” said Andersen, a paintings conservator at the Royal Danish Academy.

The brewing leftovers would have been spread over the canvases as a paste, creating a smooth surface and preventing the paint from seeping through, Andersen explained. Today, that priming process is usually done with a white mixture known as gesso.

In the study, scientists took a look at works by two of the first master painters to come out of Denmark — Christoffer Wilhelm Eckersberg, considered the father of Danish painting, and Christen

Schiellerup Kobke.

To get a peek underneath their scenes of bobbing ships and family portraits, researchers used pieces of canvas that had been trimmed off the paintings in an earlier conservation project.

The team analyzed the little strips to pick out what kinds of proteins were in them, explained lead author Fabiana Di Gianvincenzo, a heritage scientist now at Slovenia’s University of Ljubljana.

Their results showed that seven of the 10 paintings contained mixes of yeast, wheat, rye and barley proteins — some of the key ingredients for a good Danish ale.