Hi All,
This is not a discussion between Greg and me; please join in! This is one of
the great wine mysteries. Myth does not have a place in wine making anymore.
Clear bottles are a marketing thing!
Green bottles reduce UV only to a very limited extent.
The colour of a traditional wine bottle has to do with the base material
available to the bottle maker not to what is best for the wine! Just stating
that dark coloured bottles, green or brown, are the best for red wine is not
an answer. What is the effect of the many frequencies of light on wine?
Eddie V.
"Sabia Vanderzeeuw" > wrote in message
...
> Thank Greg,
> That would be great if you can find any, thanks Greg.
> This is a mystery that most wine related universities do not want to get
> into (no finance). There studies are quality related but do not include
> storage conditions As yet quality going into the bottle is more
important
> than the storage condition. The influence of light and UV on storage has
not
> seen a lot of research (no funding) to bad as we as wine makers could
learn
> a lot of this.
> The brown bottles used in beer reflect a lot (90%) of the UV radiation.
> While the green bottles only reflect 30 %. the Grolsch beer supplied in
> green bottles often has a "scunky aroma and taste". A mercaptan forms from
> the hop compounds due to UV radiation of the cynamatic acids group (sp?)
of
> the hops in the beer. This is a know problem.
> On the other hand; tannins soften due to polymerization, would a certain
> wave length of light increase this? Then we would find a way to age wines
> faster (without magnets!), but there always is a negative. What would be
the
> negative?
> Eddie V.
>
> "Greg Cook" > wrote in message
> s.com...
> > On 5/13/04 8:43 PM, in article
> ,
> > "Sabia Vanderzeeuw" > wrote:
> >
> > > Thanks Greg,
> > > The many compounds in wine will definitely absorb some wave lengths of
> light
> > > specific to the compound. Polymerization or break down can occur.
> > > Polyphenols can also break down due to UV light. There are hundreds of
> > > compounds in wine. I would like to know what families are involved
with
> > > polymerization or break down due to light. Are the flavonoids involved
> and
> > > are cinnamic acid family (phenolic compounds) involved? There are many
> more
> > > non phenolic groups are they involved?
> > > Eddie V.
> >
> > Eddie,
> >
> > Great questions. As a chemist, my chemical intuition tells me that any
> > highly conjugated compound in wine has a potential to degrade due to
> light.
> > This would certainly include phenolics, flavanoids and cinnamates.
> However,
> > I don't know specifically what studies have been done on this. If I can
> find
> > some time in the near future, I'll see what I can find in the scientific
> > literature and forward that on to you.
> >
> > --
> > Greg Cook
> > http://homepage.mac.com/gregcook/Wine
> > http://homepage.mac.com/gregcook/aws
> >
> > (remove spamblocker from my email)
> >
>
>