Integrierte Vermeidung und Verminderung der Umweltverschmutzung

Chapter 2
Before bottling, the beer is filtered through a filter cake. Proven materials for this purpose are
mud-free kieselguhr; calcined and screened diatomaceous earth of various particle size
distribution; and perlite from ground and calcined glassy rock of volcanic origin. Activated
carbon may be used to correct a mild off-taste. For example, it is usually used in the treatment
of rest beers. Shortly before filtration, hydro- and xero-silica gels may be added to contribute to
the build-up of the filter cake. Fining, by the addition of, e.g cross-linked polyvinylpyrrolidone
(PVP) and polyvinylpolypyrrolidine (PVPP) is carried out to clarify the beer and, e.g. reduce the
polyphenol concentration.
Cleaning agents and disinfectants are also used.
2.2.17 Distilling
The use of distillation in the FDM sector can be illustrated by the following two examples; the
distillations of Scotch whisky and cognac.
2.2.17.1 Scotch whisky
Distillation units in the production of scotch whisky range from simple pot stills to continuous
multicolumn stills. Energy is introduced in the form of steam to the bottom of the still and
selectively volatilises the alcohol and other components from the fermented liquids and predistilled
alcohol/water mixtures. The volatile components are recirculated within the still to
achieve the correct separation, selection and concentration of alcoholic/aqueous compounds for
the many varied and desirable congener profiles required by the various types and brands of
products. Stills can be operated singly or in series. The volatile components are condensed by
heat-exchange with water in condensers and removed as a liquid spirit. The residual material
known as pot ale, spent lees, stillage or spent wash, is discharged from the bottom of the still. In
column stills other fractions are also removed such as fusel oils and high feints. The high feints
are fed back into the stills and the fusel oils, which are mainly amyl alcohol, are sold as a coproduct.
2.2.17.2 Cognac
Cognac is obtained by the distillation of white wines harvested in the controlled appellation
area. The distillation of Cognac is a two-stage process. In the first stage, a first distillate, known
as “brouillis” is obtained. This has an alcoholic strength of between 28 to 32 % volume. In the
second stage, the brouillis is returned to the boiler for a second heating, known as “la bonne
chauffe”. The distillation heads, secondes and tails are separated, leaving only the heart of the
spirit. There is a restriction on the maximum strength of distillation, which must not exceed
72 vol-% alcohol. The time of each stage is about 12 hours.
Distillation is carried out in two separate heatings or chauffes in a special Charentais copper pot
still comprising a characteristically shaped boiler, heated with a naked flame and topped with a
cowl shaped like a turban, an olive or an onion. A Charentais still often has an energy saving
wine reheater. This device, in which the heat is provided by the alcohol vapours passing through
it, preheats the wine, which is to be distilled in the next cycle. The final day for distillation is
31 March of the year following harvesting.
Maturation must be carried out in Limousin or Tronçais oak casks. As with other brandies and
matured wine spirits, maturation was aided by the use of oak extracts, but this practice is
becoming less common in Cognac. French regulations prohibit the use of additives in the final
product, other than water and sugar or caramel, and restrict the minimum strength to 40 vol-%
alcohol.
108 January 2006 RHC/EIPPCB/FDM_BREF_FINAL