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The character and authenticity of the Czech beer, which has been accorded the protected geographical indication (PGI) Ceske pivo by the EU, are based on specific technology and use of unique raw materials. A number of chemical and sensorial markers of the Czech beer differ from those of other lager or Pils-type beers. The majority of Czech beers contain residual (unfermented) extract. One of the most typical characteristics of Czech beers is the difference in attenuation; its long-term recorded limit value is 4.5%. Another important characteristic typical of the Czech beer is bitterness, which is mostly higher in comparison with other lagers, with the limit value at 29 EBC units. Also the colour, pH, and total polyphenol content are higher in the Czech-type beer. The limit parameters obtained by long-term monitoring were 11.8 EBC, 4.52 and 153 mg/l, respectively. Differences in amino acid and protein profiles and contents were also observed.

HPLC with amperometric detection was used to evaluate the reducing power of 23 beers and aqueous extracts of 17 barley malts. While brew pale malts were only slightly higher in electrochemical reducing capacity than natural barleys (about 1.3 g BHAE/kg), caramel malts with the colour of 60-450 deg EBC showed 7.5-17.2 g BHAE/kg. The superior reducing power of the darker caramel malts was partly due to the presence of a Maillard-derived 2,3-dihydro-3,5-dihydroxy-6-methyl-(4H)-pyran-4-one (DDMP) which was responsible for 21-55% of their electrochemical capacity. Among common brew malts, only the Munich type showed a significantly increased electrochemical capacity: 6.8+/-0.8 g BHAE/kg. In addition to the malts, the brewing can also affect the electrochemical capacity of beers which ranged from 0.4+/-0.1 to 1.9+/-0.3 g BHAE/L. Simple indigenous malt-derived phenolics were responsible for 48-57% of capacity in pale lagers and for 33-45% of it in dark and other specialty lagers. DDMP was not detected in most pale lagers, while it was responsible for up to 11% of the electrochemical capacity in dark and special beers. High-molecular-weight fraction (more than 1 kDa) of beers comprised 19-39% (pale lagers) and 14-21% (dark and special beers) of the capacity. The reducing power of malts and beers determined by the amperometric method was confirmed by a good correlation with the results of DPPH* scavenging assay.

We find out to what extent barley physiological characteristics influence the changes of malt technological properties during post-harvest storage. The malt technological properties investigated were the extract, relative extract at 45 deg C, Kolbach index, apparent final attenuation, friability, and wort beta-glucan in relation to the germination energy and germination index. On the basis of the results obtained, it was found out that the germination index is the most suitable physiological characteristic in view of the correlations with malt technological properties, mainly the extract (r = 0.57) and relative extract at 45 deg C (r = 0.77). The germination index could be therefore used in the malting industry as a suitable indicator of the malting potential.

Ancient Egyptian methods of baking and brewing are investigated by optical and scanning electron microscopy of desiccated bread loaves and beer remains. The results suggest that current conceptions about ancient Egyptian bread and beer making should be modified. Bread was made not only with flour from raw grain, but sometimes also with malt and with yeast. Brewing blended cooked and uncooked malt with water; the mixture was strained free of husk before inoculation with yeast

Industrial unhopped worts produced from different batches of commercial malt were taken to analyse the contents of compounds related to beer foam stability, such as polypeptides, polyphenols, and beta-glucan. Kolbach index of malts was also determined. Foam stability of beers produced from these wort batches was measured and the relationship between the foam stability and malt components was sought. The findings showed that the great variation in total and hydrophobic polypeptides as well as beta-glucan contents among malt batches did not substantially influence the beer foam stability. None of the studied malt parameters correlated highly with the foam stability. The results showed that it is difficult to predict the foam performance relying on the polypeptides, beta-glucan, or polyphenol contents in malt. It seems that the scope for the beer foam stability improvement by the malt selection is not considerable.

The effects of a set of barley varieties on the brewing process and quality of beer production intermediaries were studied in trial brews (40 L) prepared using the two-mash decoction process. The varieties included in the trial were selected based on the starch granule size distribution determined previously. A significant effect of the varieties on the saccharification time of both mashes was determined. The highest saccharification rate in brews was achieved with the variety Jersey; the saccharification time of the 1st and 2nd mash with the variety Tiffany was markedly longer. The varieties with a greater fraction of large starch granules (Tiffany and Luxor) exhibited a higher haze with sweet wort as well as hopped wort compared to the varieties with a low fraction of large starch granules (Jersey and Tolar). The effect on the lautering time was not demonstrated. Pronounced varietal differences were determined in the extract balance of the brewing process. The varieties Tiffany and Luxor exhibited significantly lower extract yields. The malts from these varieties had lower laboratory extracts and higher extract losses in spent grains. The effect of the variety on the sacharide composition in hopped wort was confirmed. The proportion of fermentable saccharides in hopped wort extract rose from the variety Tiffany (66.9%) to the variety Jersey (83.6%). A significant difference in the final attenuation was also determined (76% in beers prepared from the varieties Tiffany and Luxor compared to 81.5% from the Jersey variety).

A simple, fast and cheap test suitable for predicting the course of brewery fermentations based on mass analysis is described and its efficiency is evaluated. Compared to commonly used yeast vitality tests, this analysis takes into account wort composition and other factors that influence fermentation performance. It can be used to predict the shape of the fermentation curve in brewery fermentations and in research and development projects concerning yeast vitality, fermentation conditions and wort composition. It can also be a useful tool for homebrewers to control their fermentations.

Brine shrimp and conductimetric Saccharomyces cerevisiae bioassays were used to investigate the toxicity of green barley malt prepared at 16 and 25 degrees C from grain inoculated with a strain of Aspergillus clavatus known to produce the mycotoxins cytochalasin E and patulin during malting. Pure cytochalasin E was considerably more toxic to brine shrimp larvae than patulin (LC50 0.5 versus 30 micrograms ml-1). In contrast, patulin significantly inhibited growth-related change in conductance of S. cerevisiae cultures at a concentration of 10 micrograms ml-1, but cytochalasin E had no effect at 80 micrograms ml-1. Extracts of both 16 and 25 degrees C malts contaminated with A. clavatus were toxic to brine shrimp larvae, but had only limited inhibitory effects on the growth of S. cerevisiae. Since concentrations of cytochalasin E in contaminated malts produced at 16 degrees C are below or close to the limits of detection, the presence of other fungal metabolites toxic to brine shrimps in such malts is indicated