Filtering and S02 adjustments

[Runningwolf]

There is lots of conversation about sterile filtering. I just wonder how many folks and wineries that sterile filter are using good filters. In other words, filters have a life span. When I sterile filter the filter is rinsed then cleaned with Caustic Soda, flushed with meta/citric solution and then stored in the fresh meta/citric. I'm sure that is the basic practice with many others but how many test to see if the filters are still actually truely sterile filtering. I did test mine after about 6 months of running many thousands of gallons of wine through them and they both tested out ok.

This is not a test I could do at home on my enolmatic filters. I do treat the enolmatic filters the same way except I use oxy clean instead of caustic for cleaning them. I only use .2 and .45 micron filters for filtering at home with all wines.

Again as Malvina mentioned I am a believer in higher amounts of S02 prior to filtering and bottling.

 

[ibglowin]

OK I'll bite.

How do you test to see if the filters are still actually sterile filtering?

 

[Runningwolf]

It's not hard but there has to be a standard set by the filter company that you are using. With ours we set up a t-valve on each side of the filter and ensure it is good and wet (not filled with water). We feed nitrogen through the inlet and have a small hose coming out the exit. That hose goes into a bucket out water. There is a pressure guage on the filter unit. If any nitrogen passes through the system, creating bubbles in the pail of water before 20psi it fails the test. Again this may not work for other filters but this is the standard that was set for this company.

 

[ibglowin]

I don't see the correlation between 20psi (pressure) and a 0.45u (pore size) filter. I would think whatever gas your using the molecules are way smaller than 0.45u (more than likely in the picometer range) thus passing easily through the filter.

What am I missing?

 

[MalvinaScordaad]

I have no idea either? Are we testing for bacteria?
Malvina

 

[KevininPa]

I believe what Dan is referring to is the Bubble Point test.
http://wine.appstate.edu/sites/default/files/Bubble Point Test.pdf

 

[MalvinaScordaad]

Thanks for that link. My question is there a different bubble standard for a Absolute Filter as compared to a 99 percent filter of the same micron rating?
Malvina

 

[ibglowin]

Thanks Kevin!

I believe what Dan is referring to is the Bubble Point test.
http://wine.appstate.edu/sites/default/files/Bubble Point Test.pdf

 

[Runningwolf]

Kevin, thanks for posting that link. I had the exact same report at work and was waiting to pick it up to respond. Now I have an electronic copy of it. Malvina, sorry but I do not have an answer to you question "is there a different bubble standard for a Absolute Filter as compared to a 99 percent filter of the same micron rating".

 

[MalvinaScordaad]

I hope my question is understood or for that matter makes sense. If you are worried about the effectiveness of a filter, wouldn't a new 99 percent grade filter pass a test for its micron rating? If so, and I assume so, then if an absolute filter is know longer absolute could it still pass the test as 99 percent effective?
Malvina