The goal of steaming the barrel is to kill the bugs (yeast and bacteria) living inside the wood. Its unlikely that one would be able to kill ALL the bugs, but steaming them should kill the vast majority. What I'm trying to do here is make an environment in which the desired concoction of bugs can be added and will be able to take over.
Given that this is my first time using this barrel, I first needed to soak it with hot water to extract the wine flavor from the wood. I did this by turning my water heater up to the highest heat. Once heated I connected a hose to my basement wash basin and turned on the hot water. As you can see from the following picture, the water entered at ~170 degrees.
The steaming process on the other hand penetrates deeper into the wood and pushes out the wine. After I finished steaming there was a puddle of dark liquid at the bottom of the barrel. My final step in cleaning was to give it a final rinse by completely filling and emptying the barrel.
The next step will be to "prime" the barrel...