Once fermentation is complete I noticed that Lager beers do have a rather sharp taste. Although they will clear out quite naturally over time, they will never be crystal clear either. A very small unnoticeable haze is still present.
It seems that filtration is a touchy subject, and indeed it is! Taste will certainly go away. The question whether this is desirable or not is up to the manufacturer to decide. In some instances I found that it is desirable, in others I found that it results in an inferior product. What I noticed is that it will certainly make the beer brighter and the loss in taste needs to be compensated for in the grist composition. The good news is that with Lagers a lot of unpleasant tastes disappear quite rapidly — which shortens the conditioning time and can indeed produce a very fine drink. It’s up to the brewer to compose the correct grain bill as well as to experiment which grade of filter is appropriate.
Once my beer is ready it is usually quite clear already. This is a good because it allows to skip one pass and proceed directly to the polish phase.
For wine as well as for beermakers, a very handy pump with plate filters is available. The pump can be used without the filter plates and I use it to transfer wort. It is marketed under different names but is essentially the same product. The directory section in this blog lists companies stocking this product.
First the holding plates of the filter are cleaned thoroughly. Note that leaving the cleaning solution in the sink is a good idea so one can re-use it to clean the plates after the procedure.
Then I rinse them a couple of times to ensure no cleaning solution is present. Being able to work outdoors is definitively a plus. It’s quite a wet process, regardless how much care is taken. I have two water supplies. One which is directly from the mains, the other goes through an active carbon filter. It is advisable to use the filtered one for the rinsing to ensure no Chlorine is present.
Then I assemble the plates. It’s not rocket-science. Note the green grommets which prevent excess fluids dripping. Note that fluids will exit the filter, no matter what. I’ll come the expected losses a bit later.
Now the actual filter sheets are immersed in boiling water. One of my mash tuns is used for this. Introducing oxygen at this stage will have a disastrous outcome, so it’s a good idea to boil the water first in order to drive out any oxygen trapped in the water.
The plates are cardboard. They need to be soaked for about 30 minutes to avoid unpleasant off-tastes. Some off taste will result as part of the process. My experience has shown that they disappear after about a week.
Cleaning the kegs. Again, de-chlorinated water is used. I made myself a little adapter for the hose which makes it quite convenient and fast! Then I fill half of one keg with sanitiser.
After a minute I turn the keg upside down to sanitise the other half. Maybe I’m overly economical here, but why have unnecessary waste?
Undruecken is a versatile technique. Here it’s used to transfer the sanitiser from one keg to the next. It also has the nice side-effect that it purges the keg from oxygen. The lids won’t be opened any more after this stage, providing a virtually oxygen-free environment.
Here is the unit with the filter sheets inserted. At the end of the hose is another self-build contraption which I use for transferring beer from the fermenter into the kegs, as well as for pumping beer into or out of kegs. I find it quite versatile and inexpensive.
Then the filter is flushed again by circulating 20 litres of water through the sheets in order to drive out any off taste that the cardboard sheets may produce. I also flush the system with CO2 once the recipient keg is connected in order to purge the system from any oxygen.
Introducing Oxygen at this stage will seriously damage your beer! I even purge the water I flush the filters from Oxygen. This can be achieved by either bubbling CO2 through the water, or simply boiling it for 20 minutes.
WARNING: working with items under pressure can be tricky. Eye protection should be worn. There will be fluid leaking through the filter plates. It’s unavoidable. Note the strong construction. It’s made this strong so one can really tighten the sheets.
FIP – Filter In Place
Now that we know about CIP (Clean In Place) meet my little “invention” of Filter In Place! There is no need to lift the heavy kegs in and out. The light and empty receiving keg is put in the freezer, the label from the original keg transferred.
Note that the whole circuit would work under pressure too. I pressurise it to 1BAR from the origin keg, but I also switch on the pump to aid it’s transfer through the plates.
One nice side-effect of filtering under pressure is that the beer also carbonates a little!
- Connect a Spundapparat
- Leave the bleeder valve open
At the very end I measure the losses. 0.817l over 60l which equates to 1.35% loss. I find it acceptable.
Now the plates and seals are returned back to the sink where they can be cleaned by re-using the solution from before. And here is the result. Perfect beer for this weather!