Yeast behind velvety stout may have Silk Road origins

The study showed that yeast used to brew the perfect lager can also be pressed into service to produce excellent stout. Photograph: The Irish Times

There is nothing more Irish than the pint of plain but a DNA analysis of the yeast used to brew stout shows its origins are actually in India.

The same study also showed that yeast used to brew the perfect lager can also be pressed into service to produce excellent stout.

A research effort to build a comprehensive family tree of yeasts is under way, involving researchers from Trinity College Dublin and University College Dublin.

It even sampled naturally occurring yeasts in the wild.

There are two main groups of yeasts used to brew lager, and the researchers found that one of them shares DNA with the yeasts used to make stout.

But this DNA is also shared by a yeast strain used to brew Toddy, a speciality from southern India.

The research had uncovered new links between stout, ale and lager yeasts, said Prof Ursula Bond, associate professor in microbiology at Trinity.

The shared links joining stout, lager and Toddy yeasts also hinted at a colonial exchange of yeast strains between India and these islands some time in the past, she added.

There seems to be a link there. We are sequencing the genomes to see.

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Yeast behind velvety stout may have Silk Road origins