[rikun]

The middle will cool properly, that's where my internal probe is. Well at least according to recommendations here, in less than four hours under 42F.

With the outside freezing a bit more, it can be done in less than two hours.

Maybe I'll try doing a "hybrid water ice bath" placing a big container of water with some ice blocks in the freezer and keeping it cool just above freezing. And chill in that water bath in the freezer.