Usually when I buy beef, I put it in the fridge, uncovered, for a day before I prepare it. This time however, I bought it 3 days in advance because good quality meat tends to run out around Christmas here.
I'll make beef Wellington, so my idea is to put it in the fridge to let it become as dry as possible, to prevent it from soaking the pastry. (Of course, the duxelles en prosciutto will also assist in achieving that.)
Will the tenderloin get too dry after 3 full days in the fridge, uncovered?
I don't know if much moisture leaves the meat through evaporation from more than just the very outside, even with a longer wait. I would be surprised if this made a big difference to the quantity of juices released during cooking, so intuitively I would not share your worry about the steak getting too dry.
However, I would worry about an uncovered steak getting dirty, absorbing unwanted smells or flavours, or having some kind of pathogen or mould growing on it. If you want to give it a go a good way to do it with less risk would be to put it in an airtight Tupperware container big enough for there to be space around the steak, with some kitchen roll in the box to absorb any moisture released. Changing the paper if it gets damp should be enough to keep the air inside the box dry.
