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Processability of malts from UK-grown barley (2001/2002)

HGCA PROJECT REPORT 283

PROCESSABILITY OF MALTS FROM UK-GROWN BARLEY (2001/2002)

by

D BAXTER

Brewing Research International, Lyttel Hall, Coopers Hill Road, Redhill, Surrey RH1 4HY

JULY 2002

Abstract

EXECUTIVE SUMMARY

1. Nine commercial malts, each of which conformed to a typical premium lager malt specification, manufactured in Europe , North America or Australia , were obtained from international brewers who routinely sourced their malts from these areas.

2. Each sample was subjected to a battery of standard and non-standard tests, some of which were designed to predict some aspect of processability during brewing.

3. Six of these malts were selected for pilot brewing trials on the basis of their standard analyses. At least one malt was chosen from each of the growing areas described above. Where possible, two malts from the same brewer were selected.

4. Each of the selected malts was brewed in BRi's pilot brewery according to three different brewing regimes;

(a) BRi's standard premium lager protocol, which is very well characterised and utilises a high proportion of malt in the grist

(b) A recipe based on those used by commercial brewers who regularly use a high proportion of unmalted adjunct (maize grits) in their grists. The intention here was to investigate the fermentability of the malt.

(c) A recipe containing a significant proportion of undermodified malt, to investigate the cytolytic capabilities of the malt

5. The brews were monitored for indices of processability during brewing and fermentation. Worts and beers were analysed by standard industry methods.

6. The brewing results showed that although the malts had similar standard specifications, their processability in the brewery differed significantly, particularly in terms of ease of lautering in the brewhouse.

7. Overall, the two UK malts had the highest processability scores. However, the number of samples processed was insufficient to draw any firm conclusions as to whether there is a real link between geographical origin and processability.

8. The high malt grist protocol gave the most useful information. The other two brewing regimes supported this but did not add any new information. If this work were to be extended, it is recommended that a larger number of malts should be processed by a single brewing regime.

9. None of the predictive tests used gave a totally reliable indication of processability. Some parameters showed a higher correlation with processability than others, but a larger number of samples would need to be processed in order to make firm recommendations. However, it was apparent that several of the tests currently used gave redundant information and there were indications that a combination of two or three carefully selected tests would be most useful for predicting processability.

10. There were indications that malts from some laboratory tests, particularly those involving cell wall modification, gave anomalous results with certain non-European malts. It is recommended that this should be taken into account in the development and calibration of predictive laboratory tests.


HGCA Project Number: 2460
Price: £5.50

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