Presenter: Rob J. Arnold, F&R Distilling Co., Fort Worth, TX
The budding yeast Saccharomyces cerevisiae has been
associated with human activity for several millennia due to
its use in a variety of processes, including the fermentation
of alcoholic beverages. The species has also been intensively
studied in the laboratory, being used as a model organism
for genetics and molecular biology. It was the first eukaryote
genome to be sequenced, and its 12 Mb genome is better
annotated than any other eukaryotic organisms. The intensive
research that surrounds S. cerevisiae has revealed surprising
data that could prove groundbreaking with regard to the
production of alcoholic beverages. In 2011, there were five
known lineages of S. cerevisiae: wine/European, North
American, Malaysian, West African, and sake. In the Western
world, most industrial yeasts (brewing, winemaking, etc.) come
from the wine/European lineage (Warringer et al., PlOS Genet.,
2011). Data from the Warringer et. al. study revealed that each
lineage possesses population-specific traits that are unique to
one lineage. Traits (or phenotypes) result from the expression
of an organism’s genes, and genes control the expression of
proteins that facilitate the catabolism of wort components into
ethanol and aroma compounds. Therefore, it can be argued that
population-specific traits among lineages could result in either
the production of novel aroma compounds or the production
of already known aroma compounds at strikingly different
concentrations than are normally observed. In 2012, a Chinese
expedition revealed eight new lineages of S. cerevisiae that
were unknown to science: CHN I–CHN VIII. Interestingly,
CHN I was revealed to be ancestral to all known lineages,
making China the proposed origin of the species. If the
argument that lineages contain population-specific traits is true,
the discovery of eight new lineages could produce a wealth
of novel aromas to be incorporated into alcoholic beverages.
Furthermore, when one considers that the Western world
has only utilized one lineage industrially, there are at least
11 lineages that could be explored for beverage production.
Indeed, at least some of the lineages other than wine/European
are suitable for beverage alcohol fermentation, with the sake
and West African lineages being used for the production of
sake and African being used for wines and beer, respectively.
In 2011, Firestone & Robertson’s Head Distiller Rob Arnold
isolated 11 S. cerevisiae strains from a Texas pecan nut. One
of these isolates, nicknamed Brazos, is the strain used at the
distillery today. Although there is a North American lineage, all
the strains within this lineage are unable to metabolize maltose.
Arnold’s strain is very effective at maltose fermentation,
leading him to believe that the strain could fit into an unknown
or mosaic lineage. This oral presentation will cover topics on
S. cerevisiae lineages, the potential of lineage diversity with
regard to unique flavors in fermented beverages, and the data
surrounding the Brazos strain pertaining to lineage and novel
aroma compound production.
A native of Kentucky with a grandfather and multiple uncles
who worked in the bourbon industry, Rob Arnold grew up
surrounded by the distilling world. After graduating from
the University of Tennessee with a bachelor’s degree in
microbiology, he enrolled in a Ph.D program in biochemistry at
UT Southwestern Medical Center at Dallas, where he studied
microbial fermentation and analytical chemistry. Two years
into the Ph.D. program, he was contemplating leaving the
medical research field to open a distillery. While in the early
fundraising stages of pursuing that goal, he learned of the
Firestone & Robertson Distilling Co. from Fort Worth South—
the development group with which both he and F&R were
working. Rob contacted F&R and learned that they were in
need of a head distiller. After meeting with Leonard Firestone
and Troy Robertson, and realizing they all had similar visions
for bringing whiskey to Fort Worth, Rob left school early with
his master’s degree and joined the F&R team in 2011.
