The Filter Stole My Flavour

[Darren]

I've sat on the sidelines and read this with interest... but I think I might contribute something, or rather, pose a question.

From a molecular point of view, what else apart from yeast will a 1 micron filter remove? It sure as hell won't remove any alpha acids or any dextrins. What about melanoidins?

Hey Adam,

Do alpha acids or dextrins stick to yeast? $5 says they do (The aa anyhow).

Oh, and if your yeast is passing through a 1 um filter you are pushing too hard. Chances are your filter is rooted.

cheers

Darren

 

[Online Brewing Supplies]

Hey Adam,

Do alpha acids or dextrins stick to yeast? $5 says they do (The aa anyhow).

Oh, and if your yeast is passing through a 1 um filter you are pushing too hard. Chances are your filter is rooted.

cheers

Darren

Yes AA do stick to yeast! Thats why over pitching will reduce your IBU.Dextrin removal maybe , well Id rather bet on the West Coast Eagles beating Geelong.
GB

 

[Darren]

GB,

That would explain why the crud coming out of the blow-off tube is unbelievably bitter!!

cheers

Darren

 

[Adamt]

Don't need to make a bet, Daz.. I believe you!

Makes perfect sense.

 

[Online Brewing Supplies]

GB,

That would explain why the crud coming out of the blow-off tube is unbelievably bitter!!

cheers

Darren

Cant say Ive given it the suck it and see test but I will go with you on that. :lol:
GB

 

[MHB]

There is a wealth of difference between a membrane filter and a filter pad. Membrane filters are more like a sieve, just a surface with holes in it, a 1um hole wont allow any solids like bits of sand bigger than 1um through; but we have to remember that a yeast cell is rather flexible.

As an analogy you can stuff a squash ball through a 25mm hole even tho a squash ball is 40mm in diameter.

Body filters also called depth filters, consist of paper pads are made of cellulose fibres, most of them have either Perlite or Diatomaceous Earth mixed in with the cellulose.
As there are well identified dust hazards associated with both DE and fine Perlite, binding these potentially dangerous but very effective filter aids into the paper pads is one way to use them safely.

All things being equal, nothing bigger than the stated filter size is going to get through a filter pad, 1 um means 1um. This isnt the case with membranes.

If it was up to me I would refer to the two processes as filtering and sieving, might save some of the confusion evident above.

MHB

 

[Darren]

Hey MHB,

I understand what you are saying but 1um is around the size of a yeast nucleus. Having filtered many a solution I know what happens when you put too much pressure onto any filter membrane, you break it.

cheers

Darren

 

[SpillsMostOfIt]

that's a bit surprising. I use a 5um aperture and my beers are bright. Most yeast is >2um, so depending on what size your filter is, I wouldn't expect much to come through (if any).
Like I said before, commercial breweries will filter their beers at 1um or less for sterile filtration prior to packaging. This improves the shelf life and stability of the beer but can result in changes to the flavour and moutfeel. The "apparent" bitterness also changes when yeast is removed.
My tap beers only have to last a few weeks and are always stored in the cool room, so stability isn't usually an issue.
I bottle condition my bttled beers at the moment, but looking at how to filter and package a lager so it is bright and also stable enough to ship.

My beers also turn out bright - that's why I do it. I use what was sold to me as a 1um absolute filter and I use gravity as a pump. So, I get bright beers that are carbonated as they should be with a slight dusting of yeast on the base of the bottle.

I cannot argue the science, but I can speak to the results I get and I am happy.

 

[big_alk]

My beers also turn out bright - that's why I do it. I use what was sold to me as a 1um absolute filter and I use gravity as a pump. So, I get bright beers that are carbonated as they should be with a slight dusting of yeast on the base of the bottle.

I cannot argue the science, but I can speak to the results I get and I am happy.

fair enough!

 

[MHB]

Darren
Yes obviously thats right; it wasnt however the point I was addressing.

To put it more succinctly the two types of filter dont give the same results for the same reported size.
At high pressure (below the bursting pressure) you can force a lot of yeast through a membrane that has a reported porosity smaller than a yeast cell; the same isnt true for a body filter.

Unfortunately there are people trying to discuss both types as if they were the same. Its an apples and oranges situation. We need to distinguish which type of filter we are using or the discussion becomes futile (and in some cases intemperate not to mention impolite).

Personally I own both types of filter and use neither, although its nice to know I can filter any beer to sterility any time I want to, I dont like what it does to the flavour.
I also believe that patience is the 4th secret ingredient in good beer you cant fake it. By the time the beer is mature it will have dropped bright so whats the point of filtering.

Having also managed to blow through a couple of filters by applying too much pressure, it turns out that gear pumps can be a bit too good at their job sometimes, lesson learned and I get your point.

It is indisputable that filtering changes the beer, we each have to decide what works best for us, I dont believe its a right wrong choice, just whether or not the changes caused by filtering suit our needs.

MHB

 

[Pumpy]

Hi guys,

I have recently started to filter and keg my beer and i am very happy with my setup except that my 1 micron filter seems to strip a noticable amount of flavour and body from the beer. At first i thought i had diluted the beer somehow but have reproduced the results a few times now with careful methodology.

My question/s is.... Does anyone else experience this?

What i have read indicates the 1 micron is the ideal compromise between clarity and ability to retain the beers flavour. What does everyone else use?

Thanks in advance for any advice or tips for this virgin kegger.

Cheers.

'Gravity filtering' is the Go
No CO2 !!

Pumpy