If Ms. Boop is correct, I believe Dr. Shannon defined "information" as being independent of the process by which it was encoded. Whether mental or random, the process is irrelevant to the existence of the information itself.
You may have meant to say, "how do you define the process of encoding without a mental process?"
Even that is a poorly-posed question, because the limits of the question are very vague.
For example, I would suggest to you that the exchange of genetic information between sperm and egg is a form of encoding without an intervening mental process. Granted, it's a process of "mindlessly encoding" a small genetic variation on top of a much larger, pre-existing genetic theme, but a new and unique message has nevertheless been "written".
Gitt's assertion is therefore suspect (at best) on a small scale; can we really trust it on a larger scale?
I do believe Dr. Shannon had a mind. The point being is that information is a concept not a physical thing.