# Filtering Carbonated Beer



## zephon (29/9/10)

Hi All,

I am planning on filtering a carbonated beer keg to keg using the method described by Ross here.

Can someone with experience doing this clarify whether you need to operate the purge valve on the filter housing to initially fill the filter with beer or is it just a matter of setting it all up, releasing some pressure on the empty keg and waiting 30 minutes?

Regards,
Simon


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## argon (29/9/10)

simma said:


> Hi All,
> 
> I am planning on filtering a carbonated beer keg to keg using the method described by Ross here.
> 
> ...



I've done this before a couple of times... i always purge the filter with co2 first and get the whole system under the same pressure as both kegs. You can do this by connecting your gas line into the filter housing and purging the system... or my preferable method, is to to run starsan through under pressure from the empty keg, this completes 2 jobs at once... purging your system with c02 AND sanitising the filter housing and the receiving keg.

When you connect your keg of unfiltered beer to the filter, purge the filter housing and the beer will run into it. Then let the purge valve close again once the housing is full. Then connect the beer out line to the empty keg and the filtering and filling will commence. As long as you've pressurised the entire system to the same pressure foaming will be minimal.

Cheers :icon_cheers:


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## under (29/9/10)

Im keen to know how to purge the filter of air in ross's closed system filtering.


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## argon (29/9/10)

under said:


> Im keen to know how to purge the filter of air in ross's closed system filtering.



If you fill you're recieving keg with a little, say 2 or 3L, of starsan/water mixture... pressurise this keg to the same pressure as your unfiltered beer keg. Then run the starsan mixture under pressure through the filter and housing. As the liquid enters the filter housing press the red button on top till the housing is full. Now there is no O2 in the housing. The receiving keg (with starsan in it) and the filter housing (with starsan in it) is fully purged of O2. You can hold down the purge valve on the filter housing now over a bucket to let all the liquid out that was in the recieving keg. You now have a fully purged and sanitised filter housing and receiving keg ready to be connected to your full unfiltered beer keg all pressurised to the same kpa.

Connect your unfiltered beer keg to the filter housing and let it flow under gravity into the receiving keg. Do this by first opening the purge valve on the filter housing, then connect the filter housing to the recieving keg, open the purge valve on the receiving keg and beer will start flowing.

Too easy B)


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## zephon (29/9/10)

argon said:


> If you fill you're recieving keg with a little, say 2 or 3L, of starsan/water mixture... pressurise this keg to the same pressure as your unfiltered beer keg. Then run the starsan mixture under pressure through the filter and housing. As the liquid enters the filter housing press the red button on top till the housing is full. Now there is no O2 in the housing. The receiving keg (with starsan in it) and the filter housing (with starsan in it) is fully purged of O2. You can hold down the purge valve on the filter housing now over a bucket to let all the liquid out that was in the recieving keg. You now have a fully purged and sanitised filter housing and receiving keg ready to be connected to your full unfiltered beer keg all pressurised to the same kpa.



Thanks for that, sounds like a good solution.

Is there any risk of damaging the filter cartridge by pushing the starsan mixture through it under pressure?


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## argon (29/9/10)

simma said:


> Thanks for that, sounds like a good solution.
> 
> Is there any risk of damaging the filter cartridge by pushing the starsan mixture through it under pressure?



as long as you do it at a relatively low pressure it's fine... alot of people force filter under gas... alot of people use gravity only. Just don't crank it up to stupid pressures and you'l be fine... serving pressure or just under is good.


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## Ross (29/9/10)

To Filter carbonated beer you must filter under a pressure greater than the carbonation level or your beer will go flat.
The closed loop method i posted here is the simplest & best way of transfering or filtering carbonated beer.
http://www.aussiehomebrewer.com/forum/inde...showtopic=16907


Cheers Ross


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## under (29/9/10)

Rossco. With that mate. We are talking about how to purge the filter of air in your closed system transfer. Either noone is explaing it, or im a complete dumbass.

This is the way im looking at it

1. Increase full keg above carbonation level to 120kpa
2. Fill empty keg with c02 to 120kpa
3. Connect filter to full keg, bleed air until filter is primed. Reconnect keg to gas so the keg and filter is back at 120kpa (As you will lose pressure during priming)
4. Connect the filter to the receiving kegs out post, and slowly open the pressure relief to transfer.


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## Ross (29/9/10)

Before connecting the filter to the receiving keg run beer in to the filter under pressure using the relief valve to purge the air. If you prefer the filter to be purged of air first, as explained earlier in the thread either just flush with CO2 or fill with water/sanitiser & just push out with CO2, leaving the filter totally purged of air. Also give the receiving keg a good flush with CO2.
Next pressurise both the kegs to above the carbonation level of the beer (eg 120kpa) & join them together via the 2 gas posts. Then simply connect the filter between the 2 beer posts. A quick pull on the keg relief valve on the lower (receiving) keg will cause the flow to start. 30 minutes later the beer will be perfectly filtered with no carbonation loss in the receiving keg.

Hope above makes sense.

cheers Ross


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## WitWonder (25/12/11)

OK, I have a small emergency with my beer I was hoping to serve for Xmas day still awfully cloudy. I have been attempting to de-carbonate the keg over the last few days because my first attempt at filtering (which was with carbonated beer) was somewhat of a disaster however it still appears to be somewhat carbonated.

In relation to the filter, I'm still not sure how pouring carbonated beer from the keg into another vessel (filter) doesn't result in the filter just foaming up? Unless the filter housing is also under the same pressure as both the "in" keg and the "out" keg - e.g. 120kpa. Is the CB filter housing rated for this pressure or am I missing something?


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## razz (25/12/11)

Merry xmas witwonder. You need to set the system up in a tiered gravity fashion, have the beer keg highest then the filter lower and the receiving keg lower again. Keep the whole system at the same pressure and then slowly start to vent gas from the receiving keg to get the flow going. I've only tried this system once and it took quite a while to transfer.
PS. Make sure that the filter housing is screwed on tightly. Good luck
I can't help on the rating of the filter.


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## Florian (25/12/11)

you should have no troubles pressurizing the filter. Once you connect it to the kegs (which are pressurised) your filter will automatically be pressurised too. Give the filter a flush with Co2 beforehand as well, as explained above. If everything is purged and at high pressure, there won't be any foam.

It's like counter pressure bottle filling, when done right there is hardly any foam.


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## WitWonder (25/12/11)

OK thanks folks - so in this situation is it still required to fill the filter housing with beer (and if so how, given everything is under pressure) or is this only necessary when filtering uncarbonated beer to prevent oxidisation? And if I'm filtering under 110kpa of pressure, won't this damage the filter?


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## Guest Lurker (25/12/11)

I dont filter and cant offer much advice other than to observe that the pressure on the filter medium is not the inlet pressure, it is the inlet pressure minus the outlet pressure, so if the outlet goes to a pressurised keg that is slowly being bled off, you arent stressing the filter medium.


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## WitWonder (25/12/11)

Thanks GL; well I've finished filtering it and all went OK, except for the result;





Not the greatest photo from my phone but you get the idea. It's alot better than the beer was originally but still along way from what other people have posted. Note that this beer has been sitting at about 2degrees for 3 weeks and the keg was fined with gelatine originally.

Only thing odd I did observe was that the pressure dropped during the transfer (my gas lines were still connected to the CO2 bottle and reg with CO2 off) from around 110 to about 40kpa at which point I turned on the regulator again and brought everything back up to 110. Also, the beer level in the filter dropped during the transfer - I primed the filter with CO2, bled it out slowly until beer starting coming out of the relief valve on the filter and started the process. I'm not sure if this would effect filtering? I'm guessing this means there was a leak in my system somewhere but I'm stuffed if I know where. I've also noted the plastic "cage" around the filter appears as though it's coming away from the seal which I think is a bit odd;




All in all, alot of stuffing around on what is already a busy morning for a disappointing result


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## Florian (25/12/11)

If your filter did an alright job then you have probably chill haze issues. Pour a glass of beerr and let it warm up to room remp, if it gets clear then that's it.

Polyclar will help. 

My filter cage did the exact same thing the one and only time I filtered under pressure, think I might have purged it through the outlet that time. No real harm, in fact I know that others have removed the cage completely to assist with cleaning.


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## WitWonder (23/12/13)

Well, I've attempted filtering again recently, this time with another filter housing and cartridge brand new from Clarence water filters that I had sitting around for ages. I can't believe that filtering should be this hard but I reckon this is about the 6th or 7th time I've filtered beer and I don't recall having a 'bright' beer on any occasion. This time around I made a SMASH beer which, after about 3 weeks in the keg, is still as cloudy as a sample from the Swan river. So, time to set up the new filter I thought and all seemed to go fine except the result. The same results I've had with the unit I bought from CB. Again. 

Surely filtering shouldn't be this hard. Apart from getting the in/out thing mixed up, seating the filter cartridge properly, what else could I be doing wrong? Are my expectations too high - I am wrong to expect clear beer after filtering my awfully cloudy beer through a 1 micron absolute filter? It isn't chill haze either; the beer looks the same if left out overnight at room temperature.


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## Westo (23/12/13)

what psi/kpa are u pushing the beer through the filter? the quicker it goes through the less filtered it will be.


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## WitWonder (23/12/13)

About 10psi. It's pretty slow. I filtered the same beer again today and it's improved, but still by no means 'clear'. I wonder if the beer is just too cloudy for the filter and i should have maybe a two filter setup - 5 micron followed by a 1 micron? If the filter was getting blocked I assume it'd just slow down to a crawl and eventually stop (or you blow a hole in it)? Sigh.


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## Ross (23/12/13)

The 1 micron filter will only filter out yeast, not permanent haze, which it sounds like you have. If the beer has sat for 3 weeks & is still full of haze, it's highly unlikely to be yeast. I'd suggest looking at your brewing practices & maybe giving something like polyclar a go, it's highly effective in removing most hazes (not all).

Ross


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## Coodgee (24/2/16)

so after (badly) following the directions of this thread I am now stinking of stale beer, I can hardly see through my glasses due to dried beer, there are puddles of beer on the floor. I have a three quarters full keg of bright beer and two more that will remain at whatever level of clarity they are currently at. I haven't had the best morning...


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## mofox1 (24/2/16)

Coodgee said:


> so after (badly) following the directions of this thread I am now stinking of stale beer, I can hardly see through my glasses due to dried beer, there are puddles of beer on the floor. I have a three quarters full keg of bright beer and two more that will remain at whatever level of clarity they are currently at. I haven't had the best morning...


Sounds eerily familiar... I was mopping the garage floor at 10pm last night :unsure:... 

It happens, and then it goes and happens all over again.


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## moonhead (1/9/16)

Has anyone come across a situation when filtering, where the filter doesn't remain full of liquid, instead getting air introduced and thus foaming? (and oxidising the beer in the process... sigh)

Not sure how/where air could be introduced into the system, hooked up from liquid - liquid posts between 2 kegs, and pushed through with CO2...


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