Hop research | In December 2023, the latest Hop Special was published in the BrewingScience Newsletter, this time sponsored by BarthHaas. The scientific online-journal BrewingScience features peer-reviewed scientific papers with impact on the brewing industry. The brief article abstracts below provide a good initial overview of the content.

Summary | At the end of the year, our author Dagmar Hofnagel summarises the results of the 2023 spring barley harvest. The main topic remains quality and, as a result, the ability of buyers and users to compromise.

Effective hopping with blends containing Sorachi Ace

Flavour composition | Many brewers have tried to blend various hop varieties for imparting unique aromas to beers, mainly based on their experiences. If a mechanism for a hoppy aroma existed, such knowledge would help to formulate desirable blends of hops based on scientific evidence. In recent times, the mechanism of Sorachi Ace’s varietal aroma was discovered. Which hop varieties might thus be suitable for blending with Sorachi Ace hops? The following article summarises a part of the research results which have already been published in BrewingScience, 2022, issue 6, November/December.

HSI – From hop harvest to the brewery

Hop Storage Index | When evaluating hop quality, many use the Hop Storage Index (HSI) as a simple analysis to get an indication of how much the hop has been aged. The rule of thumb is: the higher the HSI, the poorer the hop variety was harvested, stored, and processed. Although HSI can be a useful tool, it is important to understand that the value should not be the sole indicator to understand the total hop quality.

Sooty mould fungus infestation on malting cereals

Underestimated risk | Mould fungi are part of the natural microbial flora of malting cereals. In recent decades, intensive research focussed on the fungus genus Fusarium plant pathogen in this respect. However, the consequences of contamination with the so-called sooty mould fungi are hardly known in comparison.

The alpha acid content of hops from the 2023 crop year with updated averages over multiple years

Overview | The 2023 hop harvest has now officially come to an end. The Arbeitsgruppe Hopfenanalyse or AHA (Hop Analysis Working Group) has announced the mean alpha acid values determined in freshly harvested hops. The German AHA members comprise the in-house laboratories of the hop processing plants Hallertauer Hopfenveredelungsgesellschaft in Mainburg, Hopfenveredlung St. Johann GmbH, HVG in Mainburg as well as the laboratories at the Hop Research Center in Hüll, the Research Center Weihenstephan, the VLB Berlin and the Technical University in Berlin, in addition to Labor Veritas in Zurich, Switzerland and IHPS Žatec in the Czech Republic. These values form the basis for any amendments to supply contracts containing “alpha clauses” for aroma hops. In the table below, each hop variety is designated by type, either as an aroma hop (A) or a bitter hop (B), according to the IHGC (International Hop Growers’ Convention) classification system.

In addition to the data for freshly harvested hops for the current crop year, the alpha acid content of the hops harvested in recent years and the updated five and ten-year averages are provided below. These serve as the basis for new supply contracts with “alpha clauses” .

Alpha acid values for air-dried hops determined according to EBC method 7.4 for freshly harvested hops for the crop years 2014–2023 as well as the average content over the last five and ten years

Barley and malt analysis from Kjehldahl method to artificial intelligence

Analysis methods | A beer is as good as its raw materials. Control using various analysis methods is required to ensure that malting barley and malt are of the highest quality. This article give an overview on how analysis developed from the first specifications of malt to up-to-date technical solutions.

GC/MS screening of volatile hop compounds

From hops to beer | The choice of the hop variety is one of the key factors that determines the final aroma of beer. During beer production, hop volatile compounds are chemically and biologically transformed to form new compounds that are not significantly present in the hop cones. To understand the complexity of these modifications and their influences on the final beer aroma, 14 hop varieties were compared for their ability to apport aroma compounds to the beer.

New mega malting facility in Brazil

A towering achievement | A malting facility known as “Maltaria Campos Gerais (MCG)” is currently under construction in Brazil, and it is certainly raising the bar for malt production. Once completed, it will boast a nominal annual production capacity of 240 000 t. The plant is slated to be commissioned at the beginning of the fourth quarter of 2023, after just under two years of planning and construction.

Hops don’t like to get old either

Hop aging | When hops age, chemical changes occur that reduce their brewing value. As long as the hop cone is on the hop bine growing in the field, no oxidation happens. As soon as the hop plant is harvested, the clock starts ticking before hops are packaged. The enemies of hops are high storage temperatures and time, as well as whether they are stored in oxidative or non-oxidative conditions. In this first part of an article series we discuss what this means for the brewer, introduce the Hop Storage Index and talk about the economic implications of hop aging.

Unique characteristics of geranic acid derived from Sorachi Ace hops

Enhancing flavour | Significant levels of geranic acid were found only in the test beer brewed with Sorachi Ace hops. This beer was brewed originally in 1984 by Sapporo Breweries Ltd. It could recently be determined that this compound has very unique characteristics, it is less odor-active but functions as an enhancer for other hop-derived flavor compounds. The following article summarises a part of the research results which have already been published in BrewingScience, 2022, issue 6: November/December.