Any issues with moisture? I find most things I freeze end up with condensation freezing inside the bag, which isn't going to be good for the coffee. I could imagine it going moldy within days of defrosting with the local humidity.
250g coffee doesn't last more than a few days for me anyway, but if you were worried about it you could split down again to 125g, so you've never got more than two or three days for mould to set in.