|
 INFORMATION
SHEET No1.
To view and print this information sheet click here
> Beer
Filtration
(or right click on the link and select 'save target
as...' option)
BEER FILTRATION
Beer filtration is normally carried out in 2 basic
stages with first the production of a bright beer and
second the production of sterile beer (if this is required).
Production of Bright Beer
A bright beer looks clear and the major amount of the
yeast and suspended solids has been removed. It will
contain a small amount of yeast.
For this filtration there are three types of beer filter
for the brewer to consider:
| 1. |
|
D.E. (or kieselguhr) pressure filters
using D.E. powder as a filter aid |
| 2. |
|
Plate and frame using D.E. (kieselguhr)
as a filter aid |
| 3. |
|
Sheet filtration using coarse/medium
grade filter sheets |
TOP
D.E. PRESSURE FILTERS
These modern beer filters are efficient, versatile,
compact and economic. They do require some training
and experience in operation.
They are especially required where the beer is cloudy
or hazy and will not settle well as they cope very well
with suspended solid levels up to 0.5%.
They are not recommended for very small quantities (anything
under 10 hl/6 Imp. barrels).
These filters consume D.E. (diatomaceous earth or kieselguhr)
powder or Perlite powder as a filter aid. This is available
in different grades of porosity and the correct grade
must be used for the filter mesh size and the degree
of clarity required. D.E. carries handling health warnings
and masks must be worn when handling it. The discharged
powder must also be disposed of to a suitable area.
The cost of powder is low and, with its high efficiency,
this makes this process the one of choice for the majority
of brewers, becoming especially important the larger
the brewery.
VELO D.E. filters are available form 2 m2 up to 100
m2 and flow rates are typically about 5 to 8 hl/hr per
m2 filtration area.
TOP
PLATE AND FRAME
This technology is now rather old as the process is
labour intensive and the process quite messy. Also the
filters are large. Whereas some automation is possible
this is costly.
They handle the higher levels of suspended solids well;
they use D.E. powder filter aid (see above).
TOP
SHEET FILTERS
These beer filters are easy to use and require very
little knowledge to run them but they do not cope well
with hazy beers as the sheets will block, entailing
replacement of the sheets prematurely. This can be costly.
This is a traditional method and requires the beer
to be fined and well settled and the use of a standpipe
in the tank to retain settled solids.
Filter sheets are consumable items. They are available
in different grades and the correct grade must be chosen.
The cost of the consumable sheets is considerably higher
than the cost of D.E. powder. This is a drawback of
this method together with its lack of versatility to
handle anything other than a fairly clear well settled
beer.
These are the filters of choice for quantities under
10 hl (6 Imp. Barrels).
Filters are available in a 40 x 40 cm or a 60 x 6 0cm
format designed to take from 20 to 100 sheets depending
on the flow rate required.
TOP
Production of Sterile Beer
This process removes practically all the yeast from
a bright beer.
There are 2 main methods of sterile beer filtration:
| 1. |
|
Sheet filtration using sterile sheets |
| 2. |
|
Cartridge membrane systems through
2 or 3 grades of membrane |
SHEET FILTER
This is basically the same filter as above for the
bright beer step but the filter should be designed and
built to a higher hygienic standard than the one for
the bright beer stage. (This up-graded specification
filter can also be used for the bright beer stage.)
The filter would be used with sterilising grade of
sheets.
Filters are available in a 40 x 40 cm or a 60 x 6 0cm
format.
NB:
One major advantage of Sheet Filters is that the 2 stages
of bright beer filtration and sterile filtration can
be incorporated into the same filter by use of a change
over or inversion plate. The unfiltered beer can be
fed in one end and sterile beer comes out the other
and so no intermediate tank is required. The beer passes
first through the coarse or medium sheets then through
the sterile sheets.
TOP
CARTRIDGE MEMBRANE SYSTEMS
The bright beer can also be pumped through a series
of housings containing a suitable number of consumable
cartridge filters to achieve the flow required for bottling.
It is recommended that the first housing contains filters
with a porosity of 10 micron followed by housings with
1 micron and finally 0.45 micron filters. For small
systems this system could be reduced to a 2 stage system
of say 2 and 0.45 micron.
This system can be installed directly before the filler
which gives increased security as it avoids the risk
of using a sterile beer tank.
NOTE: In practice both these sterilising procedures
could be used in series as the beer could be sterile
sheet filtered into a sterile tank before bottling and
then the beer can be fed into the filler through one
cartridge membrane housing of 0.45 micron. This belt
and braces system is used to reduce risks of bottling
beer particularly on fast lines and where a long bottled
shelf life is essential.
TOP
|
