What are the pros/cons of Python vs. Processing for a data collection and graphing project in a small cheesemaking plant?

Python is indisputably better at data parsing and manipulation. Processing is far better at quick, clean, beautiful data representation. I'd recommend using an approach that uses python to parse and organize data in a format that is comfortable to import and parse into processing (xml,json,csv), and then a separate processing sketch to take that data and display it. I've used this approach before fairly successfully. This modular approach might make what you eventually create a bit more portable if you'd like to use it for other projects as well.

Presumably you have the data in a database.  You can use Python or php for interacting with the database.  As for graphing, I would use Javascript or jQuery (if you cannot control the browser choice) for graphing and presentation.  There are literally dozens of sophisticated and well done libraries to accomplish all of these tasks.  Whether you use php or python to interact with the database, I cannot advise you, because of my lack of familiarity with your project.  As for the Pi, my advice to you is to make sure that your data requirements and speed are not too big to overrun the Pi. The Pi is a new machine, without industrial application history.  I would be comfortable using it to acquire data from sensors, but would be skeptical about its ability to simultaneously collect data, manage the database, and display any sort of sophisticated interactive graphics simultaneously.  I would also be leery of using the Pi to collect data in an industrial fail-safe environment.  It wasn't built for that! One of my cardinal rules is to avoid being a pioneer - especially in the area of using experimental platforms and machines in an ongoing business venture.  It's almost ALWAYS better to let others fall on their swords.  Let the technology become proven before you go risking your reputation on untried technology. I have 4 Pi s I use myself for experimentation, but I would never consider using them for a critical business project.  I advise you to remember that they were designed to allow students a low cost entry to computing.  They have limited ram and memory, and little redundancy.  They don't even have a clock!  Stay for a while with reliable stable technology until more software becomes available for your Pi. Verbum sapienti satis est.