There should be very little air pickup in the carboy receiving the wine as
the pressure would be tending to cause gas to leave the wine rather than
enter it. But in the carboy that the wine is coming from, you would still
have the normal air contact as it must be open for this to work. Normally
you would have air contact in both so maybe this would tend to cause less
air contact than normal. Of course you would have some lose of volatile
molecules due to the vacuum. There are always minuses to go with the
pluses. Still it sounds to be a very viable way of moving wine as I am
getting old and my back is not aging well. Be aware that a 3 lb pressure
drop would only lift water about 6-7 feet but that is more than enough to be
very useful to the "home" winemaker.

Question: Do you have any trouble with the hose collapsing under the
pressure?

Ray

"Lum" > wrote in message
...
>
> "Analogueman" > wrote in message
> news:IyCjc.25447$i61.3940@clgrps13...
> > Ted Underhill in his book "Making Better Wines" suggests an alternative
to
> > racking wines by gravity siphoning. With vacuum you can rack down, up
or
> > sideways and it does not involve any lifting - except, maybe, to lift
the
> > carboy you have just emptied, for cleaning.
> >
> > It involves making two holes in a bung. A vacuum source goes into one
> hole,
> > a hose from a wine source (the carboy you want to rack) goes into the
> other
> > hole and the bung is placed into a receiving carboy. Turn on the vacuum
> and
> > VOILA !!! I can empty a carboy in about two minutes.
> >
> > According to Underhill you cannot introduce air into a wine that is
being
> > vacuum racked since the wine is under negative pressure.
> >Snip.......
>
> "Cannot introduce air" seems to be a bit strong. Wouldn't there be some
> oxygen pickup due to the temporary headspace in the container being
racked?
> In addition, some oxidation would be introduced in the receiving container
> unless the pressure was extremely low.
>
> Lum
> Del Mar, California, USA
>
>
>
>