[Sca-cooks] sealing pottery

[Cindy M. Renfrow]

Hello!  There was a question several weeks ago about sealing unglazed pottery.

I ran across these recipes in Cato's De Agricultura ( On Farming), tr. by
Andrew Dalby (Prospect Books, 1998, ISBN 0907325 807), pp. 127, 151. The
first is for repairing a cracked earthenware vat. The second is for sealing
an earthenware vat to use for olive oil.

"...mend wine vats with lead, or bind with sappy oak stems.  If you mend or
bind them well, fill the cracks with putty, and pitch well, any vat can
become a wine vat.  Make up putty for wine vats as follows:  1 lb. wax, 1
lb. resin, 1/3 oz. sulphur. Put all together in a new saucepan, add
powdered gypsum till it reaches the consistency of a plaster. Use to mend
vats.  After mending, to make all the same colour: mix 2 parts raw clay
with a third part lime. Make small bricks, cook in the oven, grind and
apply."

"Coat new oil vats as follows.  Fill with amurca for 7 days; top up the
amurca each day. Then empty out the amurca and let dry. When dry:
Dissolve gum in water one day, dilute it the next. Heat the vat, not as hot
as if you were going to pitch it: warm is enough: use kindling wood for
heating.  When it is moderately warm, pour in the gum and then spread it.
If you mixed the gum correctly, 4 lb. gum is enough for a 50-urna vat."

Amurca is the watery residue leftover from the making of olive oil. Cato
sometimes uses it plain, & other times concentrates it by boiling.

"If you are to put oil in a new jar, rinse it first with amurca just as it
comes, raw; shake very thoroughly so that it soaks in. If you do this, the
jar will not soak up oil, the oil will be better and the jar itself
stronger." (p. 169)

Regards,

Cindy