Czm, Breaking in a pipe. Somebody on this huge site could probably explain it scientifically but I'm no scienitist.
Virgin briar will not lend a lot of flavor to the smoke and can burn hot. As tobacco is smoked charred carbon layer will build, the "oil" for lack of a better word, will sink into the briar. The wood will be seasoned with the flavors of the tobacco smoked and as the layer builds these flavors build, the cooling qualities improve as the "cake" on the walls of the side build. Guys that smoke pipes on a regular basis actually have to clean out this cake. For me, on most of my pipes I'm still trying to build a cake (sounds weird) I have pipes from my dad's and uncle's collection, they were both serious pipe smokers. Their old pipes have a nice burn't cake and the bowls smell sweet. Those are the best smoking pipes I have.
Hope that makes a little sense. I'm typing between commercials and my daughter keeps calling me saying dad come here X-Factor is about to start up again.. X-factor. Not my favorite show to watch but it's some family time.