[Ansteorra] unglazed pottery

[robert segrest]

One of the concerns of using unglazed pottery is lead
and other heavy metals that are usually present in
trace (and sometimes more significant)amounts in the
clay, or in the paints, dyes, and other agents used to
color the pottery.

>From a chemical point of view, while most metals can
form salts with the Cl- ion of the NaCl that you
intend to keep in the container, the Cl- will prefer
to bond with the Na+.

On the more practical side, you are putting an
abrasive substance in an clay container.  This will
mean that you will eat a little of the container when
you eat the salt.  The softer the material of the
container, the more of it you will be eating.

Truly a fired ceramic will probably not suffer much
abrasion, and it would probably take a couple of
centuries to eat enough salt for the slight
contamination of clay to have enough bad stuff in it
to matter.  That said, I personally would not
intentionally eat anything from a ceramic container
that was not glazed with an unleaded glaze.

As for period use of unglazed ceramic, we also have
good documentation of period use of other
'contaminated' materials and of the resulting lead
poisoning that appears to have been pretty commonplace
in many regions, including classic Rome.

Hope this is helpful

Laszlo

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