"MikeMTM" > wrote in message
...
> Lee,
>
> I only use my Buon Vino filter rarely, and am not an expert on
> filtration, but from what I've read, it's not so much an issue of pore
> size, but of the nature of the pores. A membrane filter is basically a
> thin sheet with lots of uniformly sized holes. the hole size is said to
> be "absolute", as there are no larger ones. A depth filter, like the
> Buon Vino pads, has a lot of different sized holes or channels, which
> have an average, or nominal, size. As Tom points out, since there are
> pores larger than the nominal size, there's a certain amount of larger
> stuff that gets past. Just because the pads are rated .5 microns doesn't
> mean they will stop everything of, say, one micron. <sigh> It takes a
> better tool than a Buon Vino, I'm afraid. Even if one could contrive an
> absolute filter for one, it probably wouldn't have the pressure to work.

That covers the subject of pad filtration pretty well.

> If anyone has found a way to do it, though, I'm all ears.

You buy a 10" 0.45µ membrane cartridge, an Ametek (or equivalent) housing
for it, some plastic fittings and hose. Hook the membrane cartridge in
series with the output of the pad filter. Presto! Sterile wine. :^)

Although membrane cartridges are expensive, you can re-use it many times if
the wine you run through it is well filtered to begin with.

Tom S