Sterile Filter or Not

[G-Man]

Hi Guys

In the UK the norm is to sterile filter beer down to 0.45microns which strips out alot of flavor & body as we know.
We have tried the sterile filtration & are not very happy with the results.

Brew Dog mention that they dont have to filter as harsh as sterile filtration thus the consumer getting a much more flavourfull beery experience. They state that they learnt this technique from the US craft breweries.

Can anyone offer how this would be possible?

Thanks Guys

[kai]

Process control

You just need control of your entire process. Keep the bad bugs out from cold wort onwards and you'll be fine. Sounds easy when put like that!

It's also worth noting that 'non-sterile' filtration can be used strip out any undesirable yeasties along for the ride.

I thought brewdog had said on their blog that they don't have to sterile filter, if they are filtering with DE (but not sterile filtering) then that will still help improve the biological (and chemical) stability of the beer.

[Filter Milt]

G-Man,
Sterile filtration depends on what you are looking to achieve. In this case, it isn't so much the um rating as much as it is log reduction. Many people use 0.45um filters assuming it is sterile, but a truly sterile filter needs to be bacterially challenged and validated that it is stopping the organisms you want to filter out.

For beer & wine, a 0.45um absolute rated, bacterially challenged filter such as a Pall NBB filter fits the bill. Unfortunately, as you mentioned, you can definitely strip flavor and profile when you go this tight. What many craft brewers in the US do is to use a "sterile" sheet filter.

Sheet filters can never be truly sterile (all sheets are rated nominally), but they do achieve a bacterial log reduction that is enough to give you extended shelf life, stability, and improve the general quality of the beer. For this type of filtration, sheet technology is gentler on the beer than membrane cartridges. You can use a Pall EK sheet in a plate and frame, or use an SDII with EK1 grade sheets to give you the low O2 pickup and no drip loss you are used to with cartridge technology. Either way you should be much happier with the fuller flavor and mouthfeel you will get.

There are obviously a lot more pieces to the puzzle, so feel free to contact me with any questions you may have. Milton_Leland@Pall.com

* Disclaimer: I work for Pall Corporation, which is the proud sponsor of the filtration section of Pro Brewer *