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Does Filtering Limit/stop Conditioning?

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Mr. No-Tip

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I've been researching filtering lately and am soon to get a 1 micron...

On the weekend I borrowed a filter and ran through a Kolsch for a comp. Being the heat of comp season, it was only ten days from brew to you - very last minute and quick and so quite a green beer was filtered. I am wondering if I can expect it to condition/improve for the next couple weeks in the bottle, even though it's filtered?

Beyond the comp beer, I think this is pretty good info to have for filter timings into the future...

I can see that Ross indicates there's enough yeast on a 1 micron to still carbonate a beer, which sounds good, but in the same thread Stagger suggests that filtered beer will not improve with age.

What's the consensus/experience?
 

the_new_darren

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I've been researching filtering lately and am soon to get a 1 micron...

On the weekend I borrowed a filter and ran through a Kolsch for a comp. Being the heat of comp season, it was only ten days from brew to you - very last minute and quick and so quite a green beer was filtered. I am wondering if I can expect it to condition/improve for the next couple weeks in the bottle, even though it's filtered?

Beyond the comp beer, I think this is pretty good info to have for filter timings into the future...

I can see that Ross indicates there's enough yeast on a 1 micron to still carbonate a beer, which sounds good, but in the same thread Stagger suggests that filtered beer will not improve with age.

What's the consensus/experience?
A 1 micron filter will remove all but "petite mutants" which will carbonate but also give off-flavours. Beer is unlikely to improve and most likely not carbonate in a bottle

tnd
 

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Yeast is absolutely necessary for conditioning of ales and lagering of lagers. During conditioning the yeast absorb a lot of fermentation by-products such as diaceyl and acetaldehyde and no doubt a stack more that I have never even heard of.

It is for this reason I carefully choose yeast strains with low floculation where possible, yeast in suspension means a faster, more thorough conditioning.

It is a well known fact that some breweries have specially constructed fermentation vessels that keep yeast in close contact with the beer. Budweiser, I understand, in the old days used beech wood chips in the fermentation vessel for this very reason, practically filling up the fermenter with the wood chips to stop the yeast settling out to the bottom.

In any case, carefully controlled conditioning on the yeast gives me ultra-clean lagers and is the main reason I don't believe in racking to a secondary (there are a few other reasons). To drop the yeast prior to bottling/kegging just hold at -2C for a week.

Steve
 

MHB

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True filtration I mean the type that takes everything out then yes the beer stops maturing from that point and will slowly (if you have done most things right) go downhill.
Which begs the question, is a 1um absolute really filtering, to my mind if some of the yeast passes the filter and we know some is getting through then its more sieving than filtering. Clearly the bulk of stuff that we would normally have to wait days or weeks to have precipitate can be stripped out fairly effectively allowing the beer to be consumed sooner whether its better for speeding up the process rather than allowing more time for the natural processes to continue is another question.
I dont know whether its just petite mutations and I suspect that may be the case with some strains of yeast or just small clumps and single cells, but enough people have bottle/cask conditioned the other side of a 1um filter that we know not all the yeast is removed.
So call it what you will I wouldnt be too worried.
Mark
 

Steve@PMF82

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I have bottle conditioned various beers after filtering with 1 micron absolute. Forget about them for at least 4 weeks to 8 weeks and they condition just like unfiltered bottles, all taste great, filtered ones are just very clear/bright.

However when kegging, the beers seem to be quite stable and stay the same throughout, only to start to go downhill after a time due to oxidation.

Make sure the beer is fully conditioned and ready in the fermenter, however long it takes for the beer to be ready. Cold condition and what not.

The beer should already be relatively clear and matured before filtering, the filter is just a final polish, not for rushing through quick beers...IMO
 

Bizier

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Budweiser, I understand, in the old days used beech wood chips in the fermentation vessel for this very reason, practically filling up the fermenter with the wood chips to stop the yeast settling out to the bottom.
They still do it today sir.
If there is one thing about AB, it is that they go to extraordinary lengths to make ordinary beer.
 
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Nick JD

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Why would you filter a beer if you intend to bottle condition it?

Filters are for beer that's carbonated with non-yeast-derived CO2, or seeded with new, fresh yeast for bottling.
 

Steve@PMF82

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Why would you filter a beer if you intend to bottle condition it?

Filters are for beer that's carbonated with non-yeast-derived CO2, or seeded with new, fresh yeast for bottling.
Yeah i agree with the sentiment.

In my case i have bottled left overs after kegging. On the rare occasion now when i deem filter necessary i will bottle the amount that wont fit in the keg prior to filtering.

I have also filtered and bottled the whole lot adding a small amount of fresh yeast at bottling, which IMO gave the quickest and best results, bottles carb up real quick like a couple of days.

Overall though the difference between a bottled beer that has been filtered and not is barely worth worrying about it. Kegging is where it is at and as i said its just a nice polish which gives swillers a great first impression. Which is 90% of the barrier with " homebrew"
 

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True filtration I mean the type that takes everything out then yes the beer stops maturing from that point and will slowly (if you have done most things right) go downhill.
Which begs the question, is a 1um absolute really filtering, to my mind if some of the yeast passes the filter and we know some is getting through then its more sieving than filtering. Clearly the bulk of stuff that we would normally have to wait days or weeks to have precipitate can be stripped out fairly effectively allowing the beer to be consumed sooner whether its better for speeding up the process rather than allowing more time for the natural processes to continue is another question.
I dont know whether its just petite mutations and I suspect that may be the case with some strains of yeast or just small clumps and single cells, but enough people have bottle/cask conditioned the other side of a 1um filter that we know not all the yeast is removed.
So call it what you will I wouldnt be too worried.
Mark
It is filtering, I reckon not sifting I did try a 0.4um beverage filter a few years back and that took so much out of the beer it was edging back to water. 1um is enough. But yes, it does allow the beer to be consumed sooner, I can't see a problem with this if the beer has been conditioned properly and for the appropriate length of time first.

As for mutant yeasts getting through the filter while the other don't, unless there's some science to back up that statement I'm going to write it off as complete crap I'm afraid, no offence intended.

I think there's circumstances where filtering is appropriate such as light style lagers which everyone kind of expects to be crystal clear, and times where filtering is absolutely wrong such as cask conditioned ales, heffes and so on.

So beer style is the best determination whether to filter or not IMHO.

Steve
 

Mr. No-Tip

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Thanks for the interesting responses, all...

The beer should already be relatively clear and matured before filtering, the filter is just a final polish, not for rushing through quick beers...IMO
Totally agree under normal circumstances, but the courier down to Melbourne sailed today, so it had to be ready. It got a couple days D rest and a couple days cold chill between FG and filtering, so it wasn't ultra green, but I'd normally have given it a few more days.


Why would you filter a beer if you intend to bottle condition it?
Not sure I would. This was CP filled from a keg just for the comp.
 

the_new_darren

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Still dont understand how a 5 micron cell (yeast) makes it through a 1 micron filter??

Its either petite mutants or the probability that the filtering membrane is rooted or some other bacteria associated with the brewing process (contaminants) that are carbonating beers previously filtered.

Anyone looked at the "majority" population of a 1 uM filtered and carbonated beer? Are they 5 or less than 1 uM?

Obviously retailers selling 1uM filters have a vested interest in not exploring these issues more fully.

Personally, I wouldn't bother filtering.

tnd
 

MHB

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A petite mutation refers to the size of the colonies formed on an agar plate, I dont know if they form smaller clumps in the brew or if the cells are smaller, just acknowledging that its a possibility, perhaps I phrased my response to petite badly, but the behaviour of petite mutation during filtration is not something on which I have any direct knowledge. I have done quite a bit of study and practice on filtering normal yeast out of beer and have a little plate and frame filter press and a collection of various grades of DE impregnated papers this is the same type of filter material used by most of the microbreweries I have seen. There is a big difference between what comes out of a 1um and a sterile filter, we once filtered a keg through a 1um then through a sterile plate and the amount of gunk on the plate was startling.

When the idea of Filtering home brew was first being mooted I put the question to some industry filtration experts and one analogy stayed with me.
Basically its a big mistake to think of yeast as a ridged solid, it isnt, the example given was you can push a 40mm squash ball through a 20mm hole
If a typical yeast cell is 3-4um and the filter is only 1um, there is plenty of opportunity for young/smaller cells to go straight through, start applying a bit of pressure and quite a few adult cells will elute through.

I dont see the point of running beer through a 1um filter, I think there are better ways to make the beer bright and that they are better for the beer; unless you are looking for true commercial bright beer but you arent going to get it with a 1um, personally I cant see the point.
Mark
 

Thirsty Boy

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what MHB said...

Petite mutants aren't called that because they are in and of themselves particularly small (although i suppose they might be), its just typically obtuse (to us) naming by frenchy biologists of times past.

Immature yeast cells, just budded, are both much smaller and also considerably more "squishy" than mature cells, they can be and are forced through a filter as course as 1micron - ergo enough yeast to carbonate a filtered beer in the bottle. Its a handy way to go if you want to bottle condition, but also to absolutely minimise the amount of sediment in the bottle. Its not something I'd bother with, but i can see its a niche type thing that could fill a need for some brewers.

BUT - the main gap i see in what most people in this thread have been saying, is that there seems to be some sort of opinion that beer cannot change and mature without yeast present. Thats just rubbish.

Many of the classic "green" flavours in beer, typically mostly VDKs and acetaldehyde need to be ironed out be yeast activity, and filtering beer with these flavours is just going to give you very clear green beer. But - if your beer isn't tasting particularly green, then there really isn't all that much for the yeast to do and they're not particularly needed. The rest of the maturation story is about chemical and physical reactions that take place independent of yeast, mostly brought about over a period of time, especially time in a very cold environment. Having filtered out the yeast doesn't stop that from happening at all.

Mind you, if you did filter it, it matters less, because the act of filtering itself takes care of a number of the things that happen when a beer matures - but certainly (assuming you have your oxidation control sorted), beer filtered through a 1micron filter will continue to mature and most likely improve over a period of time even without its yeast. And hell, its only a 1 micron filter, so you almost certainly didn't remove all the yeast anyway.

For the OP - IMO you're maybe 50/50 on whether it was the right thing to do or not. If your diacetyl and acetaldehyde levels were OK before you filtered, then you've probably helped the beer quite a lot - if they weren't, then you probably hurt it. I'd taste one. Open one up and see if it tastes green - if it does, I'd get the remaining bottles pretty warm and hope that the small amount of yeast in there does the best it can to clean the beer up while its working to carbonate. cross fingers. If it doesn't taste typically green, then let em carbonate and get em into the coldest part of the fridge - tou've done the right thing..... clean clear kolsch is a beautiful beer, probably my favourite style - yeasty kolsch tastes literally like vomit. I'll take it a little green before yeasty any day of the week.

Tb
 

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Although I mostly agree with Thirsty Boy on most points, the point made here is without clarification. (quote)

"The rest of the maturation story is about chemical and physical reactions that take place independent of yeast, mostly brought about over a period of time, especially time in a very cold environment. Having filtered out the yeast doesn't stop that from happening at all."


What physical and chemical reactions are you referring to? Can you please explain.
 

MHB

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One example would be the formation of polyphenol/peptide complexes leading to chill haze and later permanent haze, not yeast related at all. This is far from the only organic complex that can form in beer as it ages; haze is just one of the most noticeable.
Others include the formation of insoluble inorganic salts/complexes i.e. calcium oxalate or beer stone
There are a bunch of others, in my opinion most of them arent beneficial to the beer and a large fraction of the work in commercial brewing is to minimise the effects of aging so the beer remains stable.
I doubt TB was implying that yeast doesnt play a big role in maturation, just that it isnt the whole story.
Mark
 

labels

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One example would be the formation of polyphenol/peptide complexes leading to chill haze and later permanent haze, not yeast related at all. This is far from the only organic complex that can form in beer as it ages; haze is just one of the most noticeable.
Others include the formation of insoluble inorganic salts/complexes i.e. calcium oxalate or beer stone
There are a bunch of others, in my opinion most of them arent beneficial to the beer and a large fraction of the work in commercial brewing is to minimise the effects of aging so the beer remains stable.
I doubt TB was implying that yeast doesnt play a big role in maturation, just that it isnt the whole story.
Mark
Thanks, that makes a lot of sense. As you stated, most, if not all are not beneficial.

From a practical viewpoint at homebrewer level, it makes sense to keep the beer on the yeast until fermenation by-products dissipate below the taste threshold. This is also the reason I don't crash chill which can cause the yeast to become suddenly inactive whereby slowly chilling allows the yeast to aclimatise to the reduced temperatures and keep working.

As for filtering, I filter lagers with a 1 micron filter which brightens up to a clarity level which most of those in the non-brewing fraternity expect for light lager beer. My lagers end up clear in the fermenter. The yeast sneeks into the keg at the start and the end of filling and it is this yeast which I filter out. It makes no difference to the flavour and if I was the only one drinking it, I wouldn't filter. After all, I don't drink with my eyes.

I don't expect everyone to agree with these principals, but as I get crystal clear, ultra clean lagers (Pure Blonde style of summer lager beer) using Australian malt I see no need to change from these procedures. There are always new things to learn and I'm not stuck in my ways of course.

Steve
 

Thirsty Boy

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Only sort of what I meant actually.

There is the polyphenol complexing which is probably one of the big ones and a number of other things, most of which ARE beneficial, because the bad stuff happens when beer is warm, not cold. They dont constitute giant changes in the beer, but they ARE most of what makes the difference between a beer thats been well cold conditioned and a beer which has not. They aren't hard to research, I managed, I'll let you manage for yourself.

But first - ask yourself a question. Why is it do you think that you lager a beer for a long time in the cold? If it were all about yeast... wouldn't you store your beer at a nice warm temperature to let it do its work in conditions it actually likes?? Oh.. wait, people do do that. Its called warm conditioning and its what you do if all you are after is the benefits that time in contact with yeast can provide. Cold conditioning is about.... wait for it.... cold! and time spent in it. Not about yeast. The traditional drawn out Lagering process that labels is so fond of, is a combination of the two things - a long slow run down from fermentation temperatures that maintains yeast activity for quite a while, substituting time for warmth to get the same sort of levels of total yeast activity as warm conditioning. And then things get too cold and the yeast stop working (yeah yeah, they retail micro levels of activity... blah blah. They do virtually nothing instead of actually nothing) its then that the stuff that happens in the cold happens.

The point is, that there are two sets of things going on and one is not dependant on the other. Once the yeast has done its job... its job is done. Whether it did it warm or cold, fast or slow... show's over for Mr Yeastie and he can go home. Now you decide whether to cold condition the beer, and change it some more and whether you have removed the yeast will make pretty much no difference - aside from the fact that they way you are likely to have removed the yeast, ie with a Filter, in and of itself does a decent proportion of what you would achieve by cold conditioning in the first place, so you get to knock some time out of the equation (less so with a seiving filter like a 1micron pleated than with active depth filtration like a DE filter... but still a reasonable amount)

Now - none of that means that I'm saying the way labels brews his beer is wrong - or that lagering on (some) yeast is bad. It plainly isn't. Traditional lagering is wonderful and if you have the time and patience to do it, then you are managing things in a way that is at the very least, equal to any other practice. It so happens that although the things I "know" from my brewing study tell me that traditionally lagered beer shouldn't be any better than beer thats managed in other ways.... my gut feel is that its still the "best" way to do it. My own brewing isn't good enough to show up the differnence though, hopefully one day it will be.

In the meantime - I "know" both theoretically and practically. That if you give the yeast a chance to do its job (warm, cold, fast, slow - whatever) then filter it out with a 1 micron filter. The beer is good immediately, but in general and especialy for lagers and lager like beers, it will improve over a few weeks as it spends time in the cold.

So - going back to the OP - who's question is after all what we are trying to address is it not? He's making a Kolsch. A beer that is supposed to be free of the flaws yeast can clear up (mainly D and Acetaldhyde) AND is supposed to posess the lager like qualities that you get from a beer which has spent time in the cold. He filtered his beer - probably too early - what can he expect?

Well - If he took it away from the yeast too too early. He's boned. It'll probably always be a bit green and not right. Might get a bit better, might not. Sure it will stilldo all the "cold" things, but they're subtle and certainly not enough to save it from overt greeness.

However, if the yeast had done most of its work.... then filtering it will probably have helped. It will have done much of the sedimentation work that ccing does and then the rest can be done by actually getting, it into the cold for as long and as cold as possible, so there is still a chance for the beer to improve - especially given that as we discussed, there actually will be some yeast in there anyway.

He sticks aother week or so of main fermentation into that process.... and there is nothing bad about it at all.
 

drsmurto

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Some great discussion on this topic but I think i have at least one extra point to add that contradicts what has been said about yeast.

The 'job' of yeast does not stop once they have finished fermenting all the available sugars and have reabsorbed the byproducts (diacetyl, acetaldehyde etc). To assume this is the case is to make the assumption that the outside of the yeast cell wall is completely neutral and cannot interact with other molecules. This is, as you might have guessed from the way i have worded this, a false assumption. The cell wall is made up of a number of types of molecules and by way of example I will focus only on one; the mannoproteins.

Mannoproteins contain cysteine residues. Cysteine is one of only 2 amino acids that contain sulfur atoms (the other is methionine). The S part of the mannoprotein is far from 'neutral'. It is in fact, a fantastic ligand for a wide range of metal ions and is also weakly nucleophilic (a nucleophile is an atom/molecule that donates an electron as part of a chemical reaction which enables bond formation). We already know that these cysteine residues are capable of forming disulphide bridges between reactive thiols.

This is just one aspect, i could spend hours adding well studied science to this but I hope that this has opened peoples minds up to the reality that yeast are far from a neutral entity. It is an amazing little cell that performs a whole range of functions and only one of them is converting sugars to alcohols.

Filtering will reduce the numbers of yeast cells and in doing so change the way the beer can change due to the interaction of yeast and the beer matrix. So it really depends on what you are aiming to achieve, what beer style you are brewing and at what age you intend to consume it.

We could also discuss the relevant winemaking techniques which rely on extended contact between 'finished' wine and yeast in barrels for months/years as a way of manipulating the texture and mouthfeel (body) of a wine. This is due in a alrge part to yeast cells, both interacting with other molecules in the wine matrix but also the 'death' of cells which then expel their contents into the wine matrix.
 

Thirsty Boy

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Nice - thanks
 

labels

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To the original poster, accept my apologies I'm the one that sent this topic sideways. To Thirsty Boy and DrSmurto and MHB, Wow, intelligent, interesting and mind expanding discussion.

More things to think about. DrSmurto, I wish I had the time to drill down to the level you are heading, same for MHB and Thirsty Boy but my business hours won't allow that. I still consider myself to be a fairly advanced homebrewer though.

(OT) Now I am sure I have met Mr DrSmurto through activities run through Wayne from Beerbelly in times past, not sure though, there was one time in Nurioopta I vaguely remember . . . . .
 

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