Yes, huff paste would go bad eventually. But, as I said earlier, this pie is only a short-term container to allow perishable goods to get to market -- and, though the principle was unknown to medieval users, to sterilise the contents by cooking them in a sealed container, so that that they kept longer. The moist contents of the pie would also make the paste go soggy from the inside. Possibly the addition of a little suet to the huff paste would delay that.
> did you mean extracted - decanted would only
> apply to liquid?
Yes, if you want to be picky. I was using it in the extended sense of transferring the contents from one container to another.