Filter issues

[wavemaker]

Gooday all. I have a 3 keg set up in my downstairs fridge. I chose to buy and install an in line filter. One of those clear plastic vessels with filter tube inside and a blue screw on top. The inlet valve comes from the product tube of the keg to the inlet side of the filter. There is a little ball valve here that does not appear to do much. The outlet then goes to the tap on my fridge door. All connections are screw clamp on to plastic tube. No leaks apparent. My issue is that the filter empties back to the keg between beers and then delivers a frothy stream for the first couple seconds of the pour. Keg pressure is set to 8 psi and generally this works well. My limited knowledge of physics says to me that for the beer to run back into the keg there must be some sort of leak which lets the liquid travel back down the tube to the keg. I am bewildered, so any suggestions would be of great help. Merry xmas.

 

[Bribie G]

I don't have a filter but I'd guess it's similar to the bit of froth I get on my first pour, despite having a font snake font chiller in place. It comes quite simply from the CO2 gradually breaking out of the beer in the tap end of the line as it rests between sessions. Same as in pubs with the dreaded 10AM pour.

Must admit in my six year career this is the first time I've heard of an inline filter for serving, I was always under the impression that the best method was to filter the beer from primary / cold conditioning vessel into the keg in the first place as a single session then clean up the filter and store till next time.

 

[wavemaker]

Thanks for the reply and happy xmas to you. My limited knowledge of filtering had me installing in line just like a fuel filter. This needs more research. In the meantime, any suggestions would be most gratefully received.

 

[dent]

Yeah generally filtering is usually an all at once affair - use the filter between two kegs and transfer through the filter from one the other.

That said, it is possible to use it inline like you have going there. I have tried this before for different reasons, and have found it works best if there is a receiving vessel (ie, another empty filter housing) connected to the output of the filter. Have the filters set up with the base at the bottom. That way if the beer is a bit foamy coming out of the filter you can draw from the bottom of the second vessel and thus avoid the foam. The foam will then reduce between pours.

It isn't surprising that the beer will empty back into the keg, since you probably have it mounted higher than the rest of the beer, leaks or no leaks. The pressure is not a factor, since the pressure of the filter and the keg is the same. You could avoid this simply by mounting the filter down near the bottom of the keg - of course with may be inconvenient with your fridge setup.

 

[Bizier]

Yeah, it is a rule of thumb for any filtration that the optimal performance will come from an uninterrupted constant flow. Start stop pressure shocks and associated differential pressures when serving will definitely impact on performance. Whether you notice or care in your particular circumstances is another thing though.

 

[wavemaker]

Thank you all for your replies. Bare with me whilst I try to digest the info.My current process is to decant from fermenter to keg. Through the product tube I add 40 psi of co2,bleeding a enough off through the relief valve to exhaust any oxygen. I then place the keg in the fridge till it comes down to 3*c. I then force carbonate the keg and leave it with 40 psi till it is time to broach that keg. Are you saying that I should transfer the beer from the first keg to another via the filter at a constant pressure and then carbonate and serve from the second Keg?

 

[vortex]

It depends. You don't have to filter beer, you would only do it if you were looking to filter out yeast or hop trub.

Most folks won't bother filtering unless they really need to.

40psi sounds like a lot too. Do you have really long beer lines to balance that pressure?

 

[dent]

Are you saying that I should transfer the beer from the first keg to another via the filter at a constant pressure and then carbonate and serve from the second Keg?

Yeah pretty much. It is better if you carbonate after filtering, as it saves the extra hassle involved in filtering carbonated beer.

Filtering will work best if you chill the beer as cold as possible beforehand - if you can chill the beer to -1 degrees first then you will be sure you are free of any chill haze in the filtered beer that would otherwise remain.

 

[Bizier]

The low temp will precipitate proteins, but it will also cause yeast to flocc out rather than blocking your filter.

 

[wavemaker]

Hey, this is a wealth of information. Thank you all.

It depends. You don't have to filter beer, you would only do it if you were looking to filter out yeast or hop trub.

Most folks won't bother filtering unless they really need to.

40psi sounds like a lot too. Do you have really long beer lines to balance that pressure?

I only carbonate and store at that pressure. I relieve all the pressure from the keg I am about to hook up to drink and run it at 6/8 psi. Lines are about 1.5m co2 and product lines.
I will have to digest and practice. After a few days away from home. Thanks all again, see you in the new year. Travel safe.