1st Attempt At Filtering With Problems
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Thirsty Boy
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If you think about how a gravity filter system is going to work - It's either going to work by the head pressure from the top vessel pushing the beer through, or by the head pressure in the hose from filter to keg "pulling" it through via a syphon - both actually.
But, if your filter starts to block up and it's resistance become too high... Then the syphon might pull harder than the top vessel pushes, this will reduce pressure in that bit of line, and combined with the increase in temperature as the beer flows through the line - C02 will come out of solution and make bubbles in the line.
That can be a reason for bubbling - and if you are filtering very cloudy beer or for some other reason your filter is being partially blocked quickly that might be it. But that said, every time I have ever had more than a little bit of bubbling in the line, I have been able to track it down to a leak somewhere. Leak fixed, bubbling stops.
If you filter is purged of gas, and you are sure you have no leaks in the fittings... Then it has to be C02 coming out of solution, in which case it's a PITA but no actual big problem. You just have to look at your technique. We know that gravity filtering from primary works, lots of people do it successfully, so if it isn't working for you it's not because gravity filtering is no good, it's because you're not doing it right. So keep trying and learn to get it right.
Or you have a leak - find it, fix it and the problem goes away.
It can take a bit of practice to get the filtering thing right, it certainly took me a few brews before it started to work properly, and even more before it started to work properly every time.
But, if your filter starts to block up and it's resistance become too high... Then the syphon might pull harder than the top vessel pushes, this will reduce pressure in that bit of line, and combined with the increase in temperature as the beer flows through the line - C02 will come out of solution and make bubbles in the line.
That can be a reason for bubbling - and if you are filtering very cloudy beer or for some other reason your filter is being partially blocked quickly that might be it. But that said, every time I have ever had more than a little bit of bubbling in the line, I have been able to track it down to a leak somewhere. Leak fixed, bubbling stops.
If you filter is purged of gas, and you are sure you have no leaks in the fittings... Then it has to be C02 coming out of solution, in which case it's a PITA but no actual big problem. You just have to look at your technique. We know that gravity filtering from primary works, lots of people do it successfully, so if it isn't working for you it's not because gravity filtering is no good, it's because you're not doing it right. So keep trying and learn to get it right.
Or you have a leak - find it, fix it and the problem goes away.
It can take a bit of practice to get the filtering thing right, it certainly took me a few brews before it started to work properly, and even more before it started to work properly every time.
Hi,
I hope you don't mind me wading into this topic, as an ex filtration technician:
Can I ask what size is the filter? In both inches (length) and pore (micron) size?
The only reason I can see that you are getiing air bubbles appearing on the outlet side is from insuffient purging of the filter housing-I would be interested to see the set up (pictures would be very helpful).
I have noticed there are many comments about blocking of fiter element with yeast, this can be rectified by using a cascade system of filters (although blocking of filters is actually a good thing, it shows that the filter is working).
The first filter should be of a relatively large pore size.
So, if you are filtering to 1micron as a final filter, then you would need at least one if not two prefilters. The first prefilter of 5microns, the second stepping down to 2microns, then the third 1micron, or forget about the 5 micron and go straight to the 2micron- it depends on how much you value your filters.
Of course the more filters in place the lower your final output will be, this can be increased by increasing pressure to each filter at the end of filtration to ensure all liquid has been purged from the filter.
I have also seen suggestions of inverting the filters, filters are usually designed to work in one way only- so they actually filter. By inverting the filter the liquid bypasses the filter element,the filter fills up with liquid and does not allow any further liquid to enter the filter and will in fact drop out of it's collar in the housing and will no longer opearte as a filter, thus allowing all further liquid to bypass the filter and pass straight through to the outlet.
Hope this helps.
Cheers :icon_cheers:
I hope you don't mind me wading into this topic, as an ex filtration technician:
Can I ask what size is the filter? In both inches (length) and pore (micron) size?
The only reason I can see that you are getiing air bubbles appearing on the outlet side is from insuffient purging of the filter housing-I would be interested to see the set up (pictures would be very helpful).
I have noticed there are many comments about blocking of fiter element with yeast, this can be rectified by using a cascade system of filters (although blocking of filters is actually a good thing, it shows that the filter is working).
The first filter should be of a relatively large pore size.
So, if you are filtering to 1micron as a final filter, then you would need at least one if not two prefilters. The first prefilter of 5microns, the second stepping down to 2microns, then the third 1micron, or forget about the 5 micron and go straight to the 2micron- it depends on how much you value your filters.
Of course the more filters in place the lower your final output will be, this can be increased by increasing pressure to each filter at the end of filtration to ensure all liquid has been purged from the filter.
I have also seen suggestions of inverting the filters, filters are usually designed to work in one way only- so they actually filter. By inverting the filter the liquid bypasses the filter element,the filter fills up with liquid and does not allow any further liquid to enter the filter and will in fact drop out of it's collar in the housing and will no longer opearte as a filter, thus allowing all further liquid to bypass the filter and pass straight through to the outlet.
Hope this helps.
Cheers :icon_cheers:
argon
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I'm pretty sure that's what happened for me last night when filtering. The filtering pretty much came to a grinding halt with less than 500ml in the fermenter, cause i had some hop debris in the line just outside the fermenter tap. Before this i was getting a few bubbles in the line on the keg side.
Next time i'll keep an eye out for blockages, as usually i can run all the beer from the primary through the filter until it's just about empty.
under
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Im filtering now too. And I have noticed after around 10 batches going through it there are particles you can see when its held up in the light. Is this normal for a beer filtered with a 1 micron absolute? My beers are very clear but im thinking no particles should be seen (no matter how small).
Thirsty Boy
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Brauhaus,
People are generally using 10inch cratridge filters for their brew. The most popular choice would be a pleated polyester 1 micron absolute filter. The filters are stock standard sediment filters and fit into normal 10inch household water filter casings.
As such, when people talk about inverting the fitler... They mean turning the whole casing upside down, which really changes nothing about the filter operation except take potential air/gas build-up away from the in/outlets which are normally at the "top". The cartrdges are firmly sandwiched into place when the lid is screwed down, so they cant fall out of place.
Pre-filters aren't really needed even with the low pressure differential involved in gravity filtering, becquse at the end of the day, we are talking about a really quite large filter surface area and a very small amount of liquid to be filtered. I've filtered 45L of reasonably cloudy beer straight to the 1micron absolute filter, and it all went through - slowed down towards the end for certain, but all went through under no more pressure than that supplied by having the fermenter on the kitchen bench and the recieving keg on the floor.
Guys who filter double batches regularly, would generally make sure their beer was relatively clear before filtering so they get it over and done with a bit faster - crash chilling, fining etc to reduce the sediment load. But for single batches.. Hell, i filtered a whole batch and then managed to get half the yeast cake through as well a fewtimes.. Sucked an extra litre or so of good beer out of the fermenter
The filters we use, tend to be way overkill for the job, so we can be a bit more free and easy with technique and set-up.
Cheers
Thirsty
People are generally using 10inch cratridge filters for their brew. The most popular choice would be a pleated polyester 1 micron absolute filter. The filters are stock standard sediment filters and fit into normal 10inch household water filter casings.
As such, when people talk about inverting the fitler... They mean turning the whole casing upside down, which really changes nothing about the filter operation except take potential air/gas build-up away from the in/outlets which are normally at the "top". The cartrdges are firmly sandwiched into place when the lid is screwed down, so they cant fall out of place.
Pre-filters aren't really needed even with the low pressure differential involved in gravity filtering, becquse at the end of the day, we are talking about a really quite large filter surface area and a very small amount of liquid to be filtered. I've filtered 45L of reasonably cloudy beer straight to the 1micron absolute filter, and it all went through - slowed down towards the end for certain, but all went through under no more pressure than that supplied by having the fermenter on the kitchen bench and the recieving keg on the floor.
Guys who filter double batches regularly, would generally make sure their beer was relatively clear before filtering so they get it over and done with a bit faster - crash chilling, fining etc to reduce the sediment load. But for single batches.. Hell, i filtered a whole batch and then managed to get half the yeast cake through as well a fewtimes.. Sucked an extra litre or so of good beer out of the fermenter
The filters we use, tend to be way overkill for the job, so we can be a bit more free and easy with technique and set-up.
Cheers
Thirsty
Brauhaus,
People are generally using 10inch cratridge filters for their brew. The most popular choice would be a pleated polyester 1 micron absolute filter. The filters are stock standard sediment filters and fit into normal 10inch household water filter casings.
As such, when people talk about inverting the fitler... They mean turning the whole casing upside down, which really changes nothing about the filter operation except take potential air/gas build-up away from the in/outlets which are normally at the "top". The cartrdges are firmly sandwiched into place when the lid is screwed down, so they cant fall out of place.
Pre-filters aren't really needed even with the low pressure differential involved in gravity filtering, becquse at the end of the day, we are talking about a really quite large filter surface area and a very small amount of liquid to be filtered. I've filtered 45L of reasonably cloudy beer straight to the 1micron absolute filter, and it all went through - slowed down towards the end for certain, but all went through under no more pressure than that supplied by having the fermenter on the kitchen bench and the recieving keg on the floor.
Guys who filter double batches regularly, would generally make sure their beer was relatively clear before filtering so they get it over and done with a bit faster - crash chilling, fining etc to reduce the sediment load. But for single batches.. Hell, i filtered a whole batch and then managed to get half the yeast cake through as well a fewtimes.. Sucked an extra litre or so of good beer out of the fermenter
The filters we use, tend to be way overkill for the job, so we can be a bit more free and easy with technique and set-up.
Cheers
Thirsty
Hi Thirsty,
I have just had a look at the brewcraft filter, I can see what you are talking about with it being sandwiched in. I was thinking of the filters with the double "o" rings around the top which have to be pushed in to the collar, they are notorious for slipping out if they are turned upside down when full of liquid.
I think you are right about the 1micron being overkill, but it is probably a case of better safe than sorry.
Cheers
brau
Thirsty Boy
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No, I didn't mean 1 micron was overkill.. I meant the surface area and sediment handling capabilities of the filters is over kill for the job we ask them to do. If we went with pre-filters etc etc... We could use much lower cqpacity units for the small volume and small load we need to process.
1 micron is about the minimum i would consider for making beer properly bright, and thats debatable too... The difference between a 1 micron filtered beer and a 0.3 micron filtered beer is visible in the glass. But i think that filtering much tighter than 1 micron also removes too much colour and flavour.
Under - the things you can see floating in your beer, are most likely just dust. Dust that was in your recieving keg,dust in the output side of your filter or on the filter surface, dust in your glass etc. If its visible.. its too big too make it through a 1 micron filter.
1 micron is about the minimum i would consider for making beer properly bright, and thats debatable too... The difference between a 1 micron filtered beer and a 0.3 micron filtered beer is visible in the glass. But i think that filtering much tighter than 1 micron also removes too much colour and flavour.
Under - the things you can see floating in your beer, are most likely just dust. Dust that was in your recieving keg,dust in the output side of your filter or on the filter surface, dust in your glass etc. If its visible.. its too big too make it through a 1 micron filter.
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