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BIAC User Manual Installation
the pot is only half full of bleach solution. A dry stable area above, a less stable but very large
area below, and the crevice corrosion occurs at the waterline. Usually this type of corrosion will
manifest as pitting or pinholes because of the accelerating effect of localization.
A third way chlorides can corrode stainless steel is by concentration. This mode is very similar
to the crevice mode described above. By allowing chlorinated water to evaporate and dry on a
steel surface, those chlorides become concentrated and destabilize the surface oxides at that
site. The next time the surface is wetted, the oxides will quickly dissolve, creating a shallow pit.
When the pot is allowed to dry, that pit probably will be one
of the last sites to evaporate, causing chloride concentration
again. At some point in the cleaning life of the pot, that site will
become deep enough for crevice corrosion to take over and
the pit to corrode through.
It is best to not use bleach to clean stainless steel and other
metal. There are other cleaners available that work just as well
without danger of corrosion. The percarbonate-based cleaners
like PBW are the best choice for general cleaning.
If you have a particularly tough stain, liked burned malt extract,
then you may need something stronger. There are oxalic
acid based kitchen cleansers available at the grocery store
that are very effective for cleaning stains and deposits from
stainless. They also work well for copper. One example
is Revere Ware Copper and Stainless Cleanser, another is
Bar Keeper’s Friend, and another is Kleen King Stainless Steel Cleanser. Use according to the
manufacturer’s directions and rinse thoroughly with water afterwards.
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. For
passivating a larger area, or in areas that are hard to reach (such as between wedge wire or in
jackets) circulating for 30-60 minutes with a 10% citric acid solution (other acids can be used but
citric acid is food safe and readily available) at 65C/150F and letting the area fully air dry for 12
hours before rinsing is generally all that is needed to mend any damaged areas to help preserve
the fermentor and get the greatest longevity from your stainless steel. Five Star’s Acid Cleaner #5
is also effective for passivating stainless as well as removing stubborn stains and deposits (it is
available at most brewing supply stores).
Additional instructions on care of stainless can be found at the following link to the Specialty
Steel Association of North America’s guide to ‘Care and Cleaning of Stainless Steel’.
A detailed discussion on care of stainless is the Nickel Development Institute’s ‘Cleaning and
Descaling of Stainless Steel’.
Figure 10
Summary of Contents for BIAC
Page 1: ......
Page 45: ...BIAC User Manual 44...
Page 56: ...Brewing 1 2 3 4 5 6 55 Notes...
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