I poured olive oil to sit in two small ceramic jugs. One earthenware with only glaze on the interior & neck and the other in a higher fired and glazed overall jug. I wanted to see how much the olive oil would seep through the pottery.
The small jug on the left is higher fired, (out of period firing west of China). The jug on the right is earthenware, it's obvious how the olive oil soaked into the walls of the pot. The base is thicker clay and when this picture was taken after about 1 & 1/2 days it hadn't permeated through leaving the base a slightly lighter color. There is no evidence of the olive oil actually seeping through onto the paper napkin. The exterior of the little jug has no feel of oil. It appears to be staying within the ceramic.
After 2 days the earthenware jug has olive oil soaked through even the base now, although the exterior is not oily to the touch and has not left oil on the paper napkin under it. The exterior of the stoneware jug is not at all effected.
I've always suspected that is what would happen to amphorae, which were unglazed earthenware.
But an unexpected find was that the earthenware pot had been exposed to smoke although I washed it before putting oil in it and I noticed no scent. However, with the olive oil permeating the clay body the smell of the smoke is very strong. The smoke must have stayed in the porous ceramic body. This makes me wonder how much a slight, lingering flavor of smoke effected the foods that were cooked or stored in ceramics in as much as all pots were fired with burning fuel? Especially earlier pit-fired pots.
Of course foods that were cooked over the fire would be smokey flavored anyway, but this smoke might have been also infused during storage and cold food preparation.
Cooking in a much used pot could also infuse into the new dish, foods that were cooked in it previously.
How much difference would this make our recipe redactions created in a modern kitchen? I would suggest a noticeable difference.