In this work it was first shown how to quantify the gushing potential of malt with a modification of a common gushing test. Today there exist two acknowledged gushing tests for the brewing industry (Modified Carlsberg Test and Weihenstephaner Test). Both analytical methods use the overfoaming amount of a test-specific produced carbonated wort to determine the gushing potential of malt. Unfortunately the overfoaming amount can vary statistically in a way that this parameter can ¡°only¡± be used for qualitative information if the malt has a potential for gushing or not and if one malt has a higher or lower gushing potential than another one; but a precise quantitative comparison for example between two malts which both have a gushing potential is difficult..

Every year we monitor the situation concerning residues of harmful metals by screening hops immediately after harvest. In our investigations, all important European varieties from different growing areas are considered. To guarantee a representative analysis, ten samples of large lots are selected and then combined into one composite sample for each variety. The latest results for the 2009 crop are presented in the table. Metal analysis has been conducted at the “Research Center Weihenstephan”. All concentrations given are mg/kg.

In crop 2008 we showed the variations in the contribution of hop oils to beer depending on the crop year. As a representative hop aroma substance we have chosen Linalool, which correlates rather well with the sonsory impression of a hoppy aroma in beer.

The crop of spring barley this year was in many countries of the EU very good in quality and quantity.

We presented a first estimate of crop 2009 hop production at drinktec. At that time there was still some uncertainty regarding the actual crop size and alpha contents of crop 2009 hops. The figures are now clearer. Based on the updated crop size of 111.483 mt of hops there will be a total of approx. 9,942 mt of alpha acid available for the coming year.

At the Drinktec 2009 we invited visitors to taste two Pilsner type beers. About 300 people assessed our beers, brewed using 50 % each of the new aroma varieties Saphir and Smaragd. Hop dosage, based on alpha-acid content, was as follows: …

In wort and beer the hop polyphenol xanthohumol (XN) is often determined after solid phase extraction (SPE). Recently researchers described substances in roasted malts that help to enrich XN in dark beers. The carrier effect that reduces losses during beer production may influence the SPE as well. We investigated the XN recovery in dark beer samples with and without SPE sample preparation. In SPE eluates the XN recovery significantly decreased with increasing XN content compared to directly injected samples. Experiments on XN recovery in SPE passes repeatedly treated by SPE showed that this is not due to an overload of the sorbent. The use of SPE prior to XN determination in samples containing roasted substances proved to be inefficient compared to direct injection.

BrewingScience - Monatsschrift für Brauwissenschaft, 62 (July/August 2009), pp. 95-99

trans-Piceid, cis-piceid and trans-resveratrol contents of hop cones and hop pellets from six American varieties (harvest 2004) were monitored by RP-HPLC-APCI(+)-MS/MS over 12 months of storage. trans-Resveratrol, cis-piceid and trans-piceid were found in all samples. After 8 months of storage, the overall stilbene content was decreased in the same range whatever the conditioning. Absent in fresh hop cones or pellets, cis-resveratrol was released from cis-piceid in all stored samples. cis-Resveratrol concentration revealed very interesting for assessing hop freshness.

BrewingScience - Monatsschrift für Brauwissenschaft, 62 (July/August 2009), pp. 141-146

On going research further substantiate that consumption of whole grains and grain-based products is associated with health benefits and risk reduction of chronic diseases. Epidemiological studies on these cereals continue to generate an increasing interest on cereal products. This attention also concerns the beverage industry and in the present study, more specifically, malt and beer production, connected with an expansion of the market for gluten free beers. A declaration as an ecological and natural produced good is willingly carried out by the producers. Malted cereals will be appropriate for that kind of declaration because, for brewing purposes, suited malt will offer a good fermented product derived from a simple and well-known technology. More importantly, easy availability is an essential advantage.

Nelson Sauvin (NS) is a unique hop cultivar that gives a specific flavor (exotic fruit-like, Sauvignon Blanc wine-like) to finished beers. We have attempted to identify the specific flavor compounds derived from NS. First, isobutyric esters, including 2-methylbutyl isobutyrate (2MIB), have been found in the beers used with NS (NS product). These compounds had a green apple-like and/or apricot-like flavor. We next focused on certain volatile thiols that are well known to contribute to wine flavors, especially Sauvignon Blanc, and identified two new volatile thiols, 3-sulfanyl-4-methylpentan-1-ol (3S4MP) and 3-sulfanyl-4-methylpentyl acetate (3S4MPA), having a grapefruit-like and/or rhubarb odor, similar to that of Sauvignon Blanc..

The complex phenomenon of gushing occurring in carbonized beverages has been investigated in order to better understand the mechanism and to give input for further research to introduce preventive measures for the industry. The knowledge that microbubbles are stabilized through surface active substances, and in this form can induce gushing, was used to examine a selection of representative surfactants. For the analysis, a particle size distribution method was used which enabled to detect particles at nanometer level, starting from 0.8 nm onwards. The experiments using pure aliphatic surfactants (DTAC, TTAC, CTAC, ODTABr, CPC, SDS, and Tween 20) revealed that only CTAC, solved in CO2 containing table water at 2 g/l (above the critical micellar concentration), induced gushing..