1,028. Baking on Yom Tov

Shvisas Yom Tov 3:10

One may not bake in a new earthenware oven on yom tov out of concern that the oven may crack and the bread become ruined, which would mar one’s enjoyment of the holiday. One may not rake the coals of an oven but one may press them down. If the oven is impossible to use without first raking the coals, then one may do so. One may seal an oven with mud or sediment as long as it was already soft before yom tov. It is not permitted to mix mud on yom tov but one may mix ashes with water and seal the oven with that.

Shvisas Yom Tov 3:11

One may not oil a new oven on yom tov, nor rub it with a cloth or cold water in order to seal it. If it is necessary for baking, one may do so. One may not heat stones in order to roast or bake on them; one may heat and bake in an earthenware oven and one may heat water in a pot.