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Q: Mineral deposits on glassware ( Answered 5 out of 5 stars,   1 Comment )
Question  
Subject: Mineral deposits on glassware
Category: Family and Home > Home
Asked by: mosaicmama-ga
List Price: $4.00
Posted: 06 Apr 2003 20:11 PDT
Expires: 06 May 2003 20:11 PDT
Question ID: 187018
Some of my wineglasses have developed a white film that I can't get
off.  I am assuming that these are mineral deposits.  This seems to
happen to some sets of glassware and not to others.  Does a certain
type of glass have more of a tendancy to do this?  (Is there a
difference between glass and lead crystal, for instance.)  I use a
dishwashing detergent with a rinse aid.  Is there any new product on
the market that will remove this film?  If so, where is it available? 
Thank you!
Answer  
Subject: Re: Mineral deposits on glassware
Answered By: clouseau-ga on 06 Apr 2003 20:39 PDT
Rated:5 out of 5 stars
 
Hello mosaicmama,

Thanks for an interesting question!

I first found the Libbey glassware site:
http://www.instawares.com/LibbeyGlasswareGuide.asp

"Why glasses sometimes get a white film on them.

The glasses probably developed what is often called etching.

Etching is a permanent chemical alteration of the glass surface.
Etched glasses appear cloudy or hazy. Once etched, there is no
practical method of restoring the glassware to its' original
condition.

Table glassware is comprised of what is known as "soda-lime" glass.
The major ingredients are sand, soda ash and lime. Etching is a
process whereby the metal ions are removed from the glass surface,
leaving the silica exposed. Libbey's glass composition has been
formulated to offer superior resistance to etching.

The etching process is normally a very slow one. Many factors can be
involved, and the etching is usually due to a combination of those
factors. All glassware has some tendency to etch with age, as the
metal ions in the glass are slowly solubilized with repeated washings.

Etching is more likely to occur if the water is soft. Natural or
artificially softened water promotes the etching process. Soft water
tends to dissolve more of the alkaline (sodium) metal ions faster than
hard water. Consequently, the exposed silica will appear sooner. Often
the early stages of attack of the glassware are typified by the
appearance of numerous tiny scratches, which progressively increase
until the etch film is evident.

Hard water can cause filming of glassware, due to the presence of
calcium or magnesium ions and/or bicarbonate alkalinity. However, that
type of film is readily removed through acid treatment of the
glassware. The rule of thumb is that if the cloudy film cannot be
removed from the glass by acid or concentrated bleach (which will
dissolve food soil), then the film is probably etch. If a hard water
film or scale on the glass is allowed to remain there for an extended
period of time, it can have an adverse effect on the glass surface.

Proper wash temperatures are important. Wash temperatures above 150
F. will accelerate etching. At 160 F. substantial damage can occur.
Very little surface damage should be noted at temperatures up to 140
F.

Detergent concentration should be kept within the manufacturers'
recommended range. Too low a concentration can result in incomplete
removal of food soil from the glass surface. In those instances where
small amounts of soil are left on the surface, a physical phenomena
known as occlusion can take place. Occlusion means that chemicals used
in the washing process may be held by the soil and, therefore, remain
in contact with the glass for long periods of time. That can be a
factor in etching problems..."

Interesting.

Palmdale Water has a complaints page that mentions:
http://www.palmdalewater.org/TOC/Faq/WQ-Faq.htm

"THE WATER IS CAUSING SCALE ON MY COOKING UTENSILS, MY GLASSWARE ARE
BECOMING COATED WITH WHITE FILM OR SPOTS.
 
Spots on glassware or scale on taps and cooking utensils is due to
water hardness.  Hardness in drinking water is caused by two minerals,
Calcium and Magnesium.  If water contains substantial amounts of these
minerals, the water is said to be hard because making lather with soap
for washing is difficult (hard).  However, water is safe to drink
regardless of its hardness.

Hardness is measured in parts per million of Calcium Carbonate which
is identical to the mineral found in calcium vitamin supplements and
in milk.  For this and other reasons, it may be advisable to soften
only the home water that is used for washing and bathing especially if
you are on a low sodium diet.  If you believe the spots and white film
on your utensils and glassware is from a source other than hardness in
the water, please give us a call ... so that we can perform a thorough
investigation..."

And "That Home Site" has a discussion, and you will see you are not
alone:
http://ths.gardenweb.com/forums/load/cleaning/msg051216301733.html

"Strange film on certain glassware...

On certain wine glasses, I have noticed a milky film - I put them back
in for another cycle, wash them by hand, nothing removes it. We do
have hard water that is softened. I was using Cascade Gel at the time,
but have recently switched to Electrasol powder. Nothing takes care of
it. How can I get rid of this?

Follow-Up Postings:

Sounds like they are permanently etched. My DW's manual says that too
much detergent can etch some glassware. Electrosol is highly
recommended by Consumer Reports. You should not have this happen
again.

To see if it's permanent, soak the glassware in a sink of hot water
and about a cup of vinegar. If that doesn't get it off, nothing will.
 
--------------------------------------------------------------------------------

Dishwashers literally sandblast dishes with hard water minerals and
detergent, eventually permanently etching and clouding surfaces. Never
put anything of value in the dishwasher. Fine crystal and china should
be handwashed.

--------------------------------------------------------------------------------

Hopefully you are still checking this thread. I was having the exact
same problem you described. We had recently switched to Electrosol as
well. I did so because Consumer Reports said it was the best. I went
back to Cascade, and within two washings in the dishwasher with
Cascade, the film was gone!!

--------------------------------------------------------------------------------

I used to buy Electrasol all the time but I believe they must have
changed the formula because I have noticed the same thing. For me, it
is also back to Cascade.

--------------------------------------------------------------------------------

I just ran a cycle of dishes through with Cascade, and almost all the
film on my glassware is gone. I can see some little scratches like
etching, but almost no film. I may have to alternate between Cascade
and Electrasol when I notice it building up. It's probably the
chlorine in the Cascade that takes it off. But I thought with repeated
washings this could cause harm to the rubber workings in your
dishwasher.


--------------------------------------------------------------------------------

I have very hard water and have a terrible problem with this. If your
problem is the same as mine, you would get the same milky white film
if you boiled water in your pots. For me, repeated washings make it
worse. I have to soak in vinager or club soda to remove it. For me, I
think Palmolive works best but more importantly, I don't use the rinse
aid. Yes, I get spots but its better than the film.

--------------------------------------------------------------------------------

When we bought our new dishwasher about a year ago (home depot,
Maytag) the employee there told us that the type of etching that I
believe you are all talking about was caused by carbohydrate breakdown
in the water and that with the particular model we bought that would
not happen because it had such an excellent "disposal" in it. Well,
that was a big thing that we based our buying decision on and were so
excited because we had all of our glasses ruined in our last
dishwasher that way. Well...guess what. A year later and our glasses
are doing the same thing. Strange it took that long but there it is.
Incidently we have a water softner and I use an inexpensive store
brand detergent. Has anyone else heard that story?

--------------------------------------------------------------------------------

I think this problem has a lot to do with what's in your water. Years
ago I was getting that same buildup. We moved to a different city and
soon the buildup was all gone. I used the same dishwasher soap.

Now I have been in this house 6 years....used the same soap, same
dishwasher and supposedly the same water. In the past few months my
glasses are starting to get the film. We have soft water in our area.
I am wondering if it is the water and it's changed for some reason.

-------------------------------------------------------------------------------

And finally, Dishwasher Tech Tips notes:
http://www.valleyviewappliances.com/TechTips/ttdish.htm 
 

"White film or cloudiness on washed dishes

First, to determine whether the film/cloudiness is removable, soak a
glass in white vinegar for approximately 5 minutes. Rinse and dry.

1.  If the film is removed, it was due to hard water minerals and the
following recommendations should improve your results:

Adjust the detergent amount being used to the degree of water
hardness.  The general rule is 1 teaspoon of detergent per grain of
water hardness, minimum 3 teaspoons. Each line in a Maytag detergent
cup represents 3 teaspoons of detergent.  Fill both cups with the
recommended amount of detergent for normal or longer cycles. If the
cycle being used is shorter than the normal cycle, use the Main Wash
cup only....

Read all of their suggestions if the vinegar is successful.


...If the film/cloudiness is not removed after the vinegar soak, the
problem is most likely what is called etching.

Etching is a permanent pitting or eroding of the surface of the
glassware.  The beginning stages can be identified by a 'rainbow'
effect in the glassware (different shades when the glass is held at an
angle to the light). In advanced stages, the surface appears frosty,
spotted, or cloudy.

Etching can happen in any dishwasher, to any glassware, regardless of
quality. It is caused when too much detergent is used in soft water,
when items are pre-rinsed, or if the water temperature is too high. 
To prevent further etching and to keep other glassware from becoming
etched, we recommend the following:

Adjust the detergent amount to the appropriate level of the water
hardness (see above chart).

Check the incoming water temperature by turning on the hot water
faucet nearest the dishwasher. Let the water run into a glass in the
sink. Place a thermometer in the glass and note the maximum
temperature. If the temperature is greater than 60C (140F), it is
recommended that the water heater be adjusted so that the incoming
temperature is in the range of 50-60C (120-140F).

Discontinue pre-rinsing. The detergent needs the food soils to act
upon, instead of the surface of the glassware..."


So, the answers seem consistent. Hopefully, this will help to prevent
your problem in the future. And, you just *might* want to try a tip I
recall reading for this problem on stainless steel pots: try a little
rubbing alcohol. Bes ure to rinse thoroughly after trying this, but it
just might help if the problem is not from etching.


Search Strategy:

"white film" +glassware

I trust my research has helped to diagnose the problem. If a link
above should fail to work or anything require further explanation or
research, please do post a Request for Clarification prior to rating
the answer and closing the question and I will be pleased to assist
further.

Regards,

-=clouseau=-
mosaicmama-ga rated this answer:5 out of 5 stars and gave an additional tip of: $2.00

Comments  
Subject: Re: Mineral deposits on glassware
From: clouseau-ga on 13 Apr 2003 16:26 PDT
 
Thank you for the rating and tip, mosaicmama!

-=clouseau=-

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