Klarinet Archive - Posting 000793.txt from 1997/03

From: Roger Shilcock
Subj: reeds, pH, etc. (fwd)
Date: Mon, 24 Mar 1997 04:09:17 -0500

---------- Forwarded message ----------
Date: Sat, 22 Mar 1997 20:28:22 -0500
From: Bill Edinger <wde1%NYSAES.CORNELL.EDU@-----.UK>
Subject: reeds, pH, etc.

I'd hate to have everyone on the list start worrying about dissolving
their teeth, plumbing, pots, whatever in tap water that's pH 5.5, so let
me offer a clarification. Tap water, folks, is really very close to pH
7.0, just as any pure water is. The reading of 5.5 was almost certainly
due to a little-appreciated fluke of instrumentation, i.e. you can't
measure the pH of pure water (tap water is close enough) with an
electronic pH meter - it always comes out right around 5.5 (it's due to
the way pH electrodes work, or something like that which I can't recall
off the top of my head - it was one of the first things they taught us
in Biochemistry lab). This is a very common error, but believe me, if
your water were pH 5.5 you'd have a lot more problems than soggy reeds.
Regarding reed science, I highly recommend going to your local library
and copying a 1991 article in Science News (ALL public libraries will
have this) entitled "Good Vibrations - Musician-scientists probe the
woodwind reed." This will answer more questions than you would even
think of, and it's short and very readable. It addresses the question
of acids in the mouth eating away at reeds (they don't, because saliva
is alkaline, as others on the list have pointed out), reeds harboring
(viable) Streptococci (they do, so you can indeed re-infect yourself),
the role of bacteria in reed deterioration, reed treatments to prevent
this, how reed is grown and produced, and so on.
The article explains how reed structure is based on three principle
components: cellulose, gummy lignins (chemically very similar to
cellulose and just as indigestible), and moisture-holding pectins, the
latter two filling structural gaps and acting as elasticizers. Saliva
can leach out pectins, which is probably one of the key steps in the
deterioration process; another is the action of oral bacteria which live
and grow in the xylem (tubes) of the reed; and the third is a general
breakdown in the cellulose's crystal structure at a molecular level over
time. This is NOT the same as gross fiber breakdown. Storage in the
refrigerator has been confirmed as effective in slowing down both
microbial growth and chemical decomposition of reeds (Q10, anyone?).
The article is: Schmidt, Karen F. Good Vibrations. Science News, Vol.
140, pp. 392-394, December 1, 1991.
One more thing. I'm only guessing, but if the stuff that drips out of
your clarinet were saliva ("spit"), you'd never get it all out with swab
and you'd have a constantly deepening layer of white crud (dried
proteins) accumulating throughout your instrument. And your swab would
get even more disgusting than it does now, but a lot faster. It must be
almost entirely condensate.

Bill Edinger

Good stuff! However, what's wrong with pH meters nowadays? Back in the
mists of time when I used to use such things, I don't remember any problem
with neutral liquids. I seem to rememebr doing what were in effect
conductivity measurements using a buffered glass cathode, and that you had
to calibrate the thing using a buffer solution of known concentration
first. Don't people do that any more?
Roger Shi;lcock