Ella and Topaz shine at the IV International Humulus Symposium

Oct 7, 2015
A collective of brewers is a feast. A group of scientists, a sample or a force (although much debated). But a community of hop scientists?

The International Society of Horticultural Science neatly skirted the issue, titling their biennial gathering of entomologists, brewing researchers, biotechnologists and more, the IV International Humulus Symposium.

Held in August, in the USA’s hop growing heartland of Yakima, our Hop Breeder, Dr. Simon Whittock attended, presenting a paper. Naturally he also put our girls up for assessment on the world hop sampling stage.

First, the sampling

We were delighted to see our girls picked out among an international selection by the symposiums participants– a particularly proud parent moment for Simon.

In amongst 26 varieties from Germany, USA, New Zealand, South Africa, Slovenia, Czech Republic, and Norway, our Ella came out on top with the highest score for ‘overall liking’, with Topaz and our Victorian experimental variety (the only other samples named) both ranking in the top 8.

Interestingly Ella’s characteristics in beer, were picked up in the raw hop assement. See below a chart (editable excel version here or pdf here) showing the simple feedback on the organoleptic characters observed thanks to Victor at Haas.

But it wasn’t all rub and sniff tests – the focus of the symposium is hard science.

The rise of craft beer has seen a resurgence of interest in the biological processes and chemistry that underlie the experience of hop in beer. There are good presentations of this kind of work at the various IBD, EBC, ASBC, and WBC conventions.

However, there is a significant amount of hop science that goes into breeding, propagating, growing, harvesting and processing hops.

Highlights from the keynote addresses were Florence Negre-Zakarov’s (UC Davis) insight into flavour development during ripening in fruit crops and Martin Steinhaus’s (German Research Centre for Food Chemistry, Leibniz Institut) description of distinction between the many volatile compounds, and few aroma active compounds.

Thanks to the evolution of analytical technology that has underpinned development of the hop community’s understanding of the chemical drivers of hop flavour in beer, the next wave of research will focus on understanding the biology and chemistry of hop quality.

Significantly, hop genomic research was also presented that moves the community closer to a working genome sequence, and continues to elucidate some of the quirks contained within the hop genetics.

HPA’s contribution?

The continued release of novel hop varieties with uniquely identifiable organoleptic characters is evidence that the flavour potential of hops has not been fully explored. Similarly, the genetic basis of hop organoleptic chemistry is relatively poorly understood.

Simon presented a paper describing our collaborative research attempting to link the chemistry of flavour active compounds to organoleptic characterisation, and to molecular markers.

In layman’s terms, that’s research into discovering genetic flavour markers and linking the markers to what you smell and taste in beer.

Why is that important?

Hopefully, when the genetic markers and links are understood, we can then breed toward desired flavour outcomes.

In collaboration with the University of Tasmania, a mapping cross containing 166 genotypes (and the male and female parental genotypes) has been established into two replicated field trials in Tasmania and Victoria, separated by ~5° latitude.

To date two years of data on survival, plant structure, flowering, sexual phenotype, yield, and hop acid chemistry data on male and female plants has been collected. This data allows analysis of genetic variation and genotype between the two sites.

However, the ultimate aim for the study is to obtain an extended chemical phenotype, including headspace solid phase micro extraction (SPME) of hop flavour volatiles, polyphenols, glycosides, laboratory scale beer volatile SPME profiles, and integrate this with organoleptic data.

Successful completion of this hop flavoromics study will allow the identification of quantitative trait loci (QTL) in hop directly associated with beer organoleptic traits.

Full conference proceedings will be available through ISHS, to be published early in 2016.


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