The Laughing Wolf

I thought that the purpose of using a clay pot was to soak it with water first, and then put it into a cold oven, allowing the water to steam out of the porous pot slowly.

Depends on the clay pot being used. Some are done that way; others, not. For example, some people just use a terra cotta flower pot with the hole plugged, and a terra cotta base as the lid -- all those are glazed. My clay pot is semi-porous, as it tends to glaze over a bit in the same way a cast iron pot seasons. What I do is pour the beer (or other liquid) in early, so that what can soak in does. Best way is what you described, what we get is sometimes something else. All I can say is that this way worked for me this time, and I am enjoying the results for lunch today. :)