"Paul E. Lehmann" wrote in message
. ..
michael wrote:

snip

(i)both immediately after pressing(and then hope
the natural yeast
gets going after a delay) and then after first
racking.

YUP.........

I would very much like some advice.

Best regards
Michael

There is some excellent information he

http://brsquared.org/wine/Articles/SO2/SO2.htm

Although it can look somewhat intimidating at
first glance, I think you can get the main points
without getting too involved in the science.
Just be patient and read through and then go back
and get some general information or rules of
thumb to help you out. Or, if you want to
research the issue in detail, this is a good
place to start.


Michael

That link even intimidates me !! ;o)

Let me see if I can summarize just a little. ;o)

Oxydation - two kinds we are concerned with:
Enzymatic and reductive. Enzymatic is fast while reductive is
slow(er). Enzymatic is what causes fruit to brown quickly.
Cut an apple in half and you can almost see it turn brown.
SO2 inhibits/destroys these enzymes. So the more prone the
fruit is to this kind of browning, the more important it is to use
sulfite at crush. And, by destroying these enzymes, it actually
leaves_more_oxygen in the must for the yeast to use to get
started. At "aseptic" levels, SO2 also kills things like
Bot, Bret, fungus, etc. so you need to use enough sulfite at
crush to take care of these things also.

Reductive is pretty much just chemical reactions which happen
any time oxygen is present. These happen more slowly and temp
plays a large part in how fast these "ageing" reactions take place,
but SO2 slows this conciderably, so maintaining SO2 levels up
to and into bottling is also important. An "aseptic" level is also
important here to prevent certain kinds of microbial spoilage.

Go to that link and look in chapter 7 for chart number 3 and
figure number 6. These pretty much tell you the relationships
that you need to know to determine dosage required. If you
understand that an "aseptic" level is slightly higher than 0.8ppm
molecular, you should have no problem using these.

Memory ain't what it used to be. Hope others jump in and
add to this. HTH

Frederick