Sterile Filtering

Winemaking Talk - Winemaking Forum

Help Support Winemaking Talk - Winemaking Forum:

cuz

Senior Member
Joined
Mar 14, 2017
Messages
183
Reaction score
18
I have been looking at some posts on sterile filtering and have a few questions. I currently filter with a 2.5cfm vacuum pump with a 5 micron filter. I read sterile filtering requires a .45 micron filter. Then I came across an old post started by Norcal in 2016. Stickman responded in the post as follows:

Unfortunately there is no cheap .2 micron filter that works really well. The good ones are between $30 and $40 depending on where you get them from. PIWC has one for $32, it's not absolute rated, but has much greater retention rates than the typical cartridge. The absolute rated filters are twice that price, and even though they are technically the correct one to use, I've never had to go that far to prevent re-fermentation, no issues with back sweetened Riesling with bottles still in the cellar since 2005, 2007, 2011.

So does the .2 micron filter actually take out more "stuff" than the .45 micron essentially making it more sterile. The .2 micron that stickman mentions is cheaper than a .45 anyway.

My other concern is my 2.5cfm pump. Is that going to be strong enough to filter the wine through a .2 micron filter. I was thinking of staring with a 1 micron and then pass it through the .2. Does anyone have any experience filtering with a similar pump. Just want to make sure it's going to work.
 

stickman

Veteran Winemaker
Joined
Jun 16, 2014
Messages
1,825
Reaction score
1,961
The short answer is yes the .2 mic cartridge gets you "closer" to sterile, but still not sterile. A vacuum pump can work, but you need very clear wine to begin with, however you will be giving up a small amount of the filter capacity as they are rated for 35psi differential which you can't achieve with a vacuum pump (assuming both carboys are at the same elevation). The Enolmatic bottle filler uses vacuum and has a .2mic cartridge for the filtration option.

In order to understand the capability of any cartridge, you have to look at the technical data sheet. For example, the particle retention for a nominal rated Pall Poly-Fine .45mic will remove 90% of the .45 micron particles and 99.9% of the 1.2 micron particles. Compare that to the .2mic cartridge which will remove 90% of the .2 micron particles and 99.9% of the .5 micron particles. Since .45 is generally considered sterile, you can see that the .2mic cartridge is close, but misses the mark.

The right answer, for minimum risk, is to use a pre-filter followed by a sterile .45 absolute rated cartridge. I was just pointing out that, in practice, I've had no issues using a nominal .2mic with my Riesling as stated in the earlier post, several bottles which I still have at 59F in my cellar today.
 

cuz

Senior Member
Joined
Mar 14, 2017
Messages
183
Reaction score
18
I should have specified that I am filtering reds and attempting to filter out any left over yeast to prevent fermentation in the bottle. I did an MLF on some reds and backsweetened before I read why not to that. I wanted to try filtering so I don't have to use sorbate and risk the geranium taste. I have no idea what size yeast micron particles are.
 
Top