BREWHA Equipment Co Ltd. BIAC, User Manual

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BIAC User Manual Installation
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formed on the surface at the point of that damage. The good news is, with a little
cleaning and care the chromium oxide layer is self -healing...
Stainless steel and the chromium oxide layer actually thrive on proper cleaning.
For everyday cleaning of non oxidized soils, dust, dirt and fingerprints, a mild
soap/detergent (dish detergent) and warm water solution should be used. Use
the solution to remove the soil, rinsing with fresh water and a clean cloth, and dry
completely.
To clean spots (cosmetic) from the stainless
we recommend using Bar Keeper’s Friend, and
it also works well to remove rust spots and
to ‘heal’ areas that might be open to rust. A
periodic full vessel cleaning with an acid such
as citric acid or is in Bar Keeper’s Friend can
also help preserve the entire fermentor and is
recommended for getting greatest longevity
from your stainless steel.
While stainless is fairly durable, it needs to be
treated with care. Some chemical cleaners can
actually attack and degrade stainless steel. John
Palmer in his book How to Brew provides the
following summary:
For general cleaning, mild detergents or
percarbonate-based cleaners are best
for steel and aluminum. Bleach should be avoided because the high pH of a
bleach solution can cause corrosion of aluminum and to a lessor degree of
stainless steel...the corrosion inhibitor in stainless steel is the passive oxide layer
that protects the surface. The 300-series alloys (a.k.a. 18-8 alloys) commonly
used in the brewing industry are very corrosion-resistant to most chemicals.
Unfortunately, chlorine is one of the few chemicals to which these steels are not
resistant. The chlorine in bleach acts to destabilize the passive oxide layer on
steel, creating corrosion pits. This type of attack is accelerated by localization and
is generally known as crevice or pitting corrosion.
Many brewers have experienced pinholes in stainless-steel vessels that have
been filled with a bleach-water solution and left to soak for several days. On a
microscopic scale, a scratch or crevice from a gasket can present a localized area
where the surface oxide can be destabilized by the chlorine. The chlorides can
combine with the oxygen, both in the water and on the steel surface, to form
chlorite ions, depleting that local area of protection. If the water is not circulating,
the crevice becomes a tiny, highly active site relative to the more passive stainless
steel around it and corrodes. The same thing can happen at the liquid surface if
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Figure 9