Newsgroups: sci.chem
From: B.Hamilton@irl.cri.nz (Bruce Hamilton)
Subject: Re: Odor / taste from home ice maker
Date: Wed, 1 Oct 1997 07:56:53 +12

In article <875632278.6032@dejanews.com>
 Bob Peeples <rpeeple1@email.usps.gov> writes:

>Although the tap water does not appear to have a strong taste or odor,
>many home ice cube makers produce ice with an "off-flavor". What could
>cause this? I thought this was specific to my freezer until I moved
>across town (Phoenix) and my new freezer had the same problem.

It's likely to be a combination of effects.

1. Cold water and ice tastes different to ambient temperature water.
    - perhaps due to temperature sensitivity of our taste buds.
    - this could be checked by allowing the water to warm, and comparing
      it to water from the same source that was held at room temperture.

      For extra points boil some of the original water ( microwave is fast
      and efficient ), and allow that to cool to the same temperature and
      taste that immediately - and after shaking vigorously to saturate with
      air as well. You may be surprised at the difference in taste due to
      dissolved gases. The solubility of air components, such as CO2 and
      O2, increases as temperature decreases.  Additional experiements
      can involve freezing freshly-boiled water and comparing the taste.

2. The freezer is filled with volatile organics ( such as short chain
    carbonyls ) that can taint other food. Add some  water in two
    identical well-washed plastic containers ( not glass or metal, but
    only to a shallow dept to provide a large surface area to volume
    ratio ), and seal one of them. Leave both in the freezer and compare
    taste after several days. If the open one tastes different then you
    may have organic contamination.

3. It is possible that metal trays in the icecube maker may impart a
    taste to the water, and that can be checked by freezing some of the
    water in closed ( plastic film ) plastic trays of similar size and shape,
    and comparing taste both as cold ice and ambient temperture water
    - as in the above experiments.

4. The dissolved salts in water are often responsible for the taste of water,
    and water without those salts ( distilled or deionised ) also tastes
    strange. It may be that some water is condensing, or some volatile
    species are dissolving and changing the taste. The above open and
    closed experiements should help clarify that issue, as would using
    distilled water. Note that the less dissolved salts in the water, the
    easier it is to make it taste strange. When testing freezers for odours,
    unsalted butter and distilled water are routinely used because they can
    taint very easily from volatiles. Perhaps the water in your area is low
    in dissolved salts.

5. There may be biological contamination in your freezer that produces
    smells that taint.

              Bruce Hamilton