The Nature and Fermentability of Last Runnings in
High Gravity Brewing
MBAA TQ doi:10.1094/TQ-48-1-0118-01 |
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Graham G. Stewart (1), John M. H. Andrews (2),
Michaela Miedl (1), and Richard J. Taylor (3). 1. The International
Centre for Brewing and Distilling (ICBD), Heriot-Watt University,
Edinburgh, EH14 4AS, Scotland. 2. Briggs of Burton plc, Derby Street,
Burton-on-Trent, Staffordshire, DE14 2LH. 3. Wells & Young�s Brewing
Company Ltd., Havelock Street, Bedford, Bedfordshire, MK40 4LU.
Abstract
Last runnings are traditionally regarded as the final liquid at
mash-off flowing into the kettle following the separation of sweet wort
from spent grains. As the gravity decreases in the last runnings, the
major portion of the extract is fermentable sugars. Potentially
detrimental substances, such as proteins and polyphenols, have been
diluted such that they are not �harmful� if added to the kettle. If this
material is discharged into the sewer, not into the kettle, the effluent
costs because of high COD and BOD concentrations could be significant.
Wort collection can probably continue as long as the brewer does not mind
diluting the wort in the kettle for the sake of a small amount of
additional fermentable extract compared to the discharge costs. Although
full-scale trials are required, the volume of last runnings from the
lauter tun was higher than from the mash filter. However, the composition
of the last runnings from the two wort separation systems was similar.
This study did not address the question of the organoleptic
characteristics of beer under controlled taste panel conditions. However,
preliminary taste panel assessment indicates little difference in the
beers produced with added last runnings compared with no added last
runnings.
Keywords: beer quality and stability, fermentability, last runnings,
lauter tun, mash filter, wort sugars
S�ntesis
La �ltima agua es tradicionalmente
considerada como lo �ltimo que fluye de la mezcla a la paila de cocci�n
despu�s de separar el mosto dulce del afrecho. Al disminuir el porcentaje
de extracto en esta �ltima porci�n, la mayor parte del extracto es az�car
fermentable. Sustancias potencialmente da�inas, tales como prote�nas y
polifenoles, han sido diluidas de manera que no sean objetables al mosto
en la paila. Si este material se botara directamente a la alcantarilla,
los costos del efluente aumentar�an por su alta concentraci�n de DOB y
DOQ. La recolecta de esta �ltima agua podr�a continuar mientras no importe
que se diluya demasiado el mosto para recuperar una peque�a porci�n de
extracto, reduciendo a su vez el costo de la descarga a los efluentes. Si
bien esta �ltima agua ten�a la misma composici�n, tanto para un filtro
lauter y un filtro de placas, el volumen de la �ltima agua del filtro
lauter era mayor (aunque falta esto confirmar con pruebas adicionales). Si
bien no se estudiaron las caracter�sticas organol�pticas bajo condiciones
controladas, un estudio preliminar indic� que existe muy poca diferencia
entre las cervezas producidas con �ltima agua adicional que sin agua
adicional.
Palabras claves: azucares del mosto, calidad y estabilidad de la
cerveza, fermentabilidad, filtro de mezcla, filtro lauter, �ltima agua
