title_body: Brewing 900 Cups of Coffee (In 24 Hours)?
upvoted_answer: Your problem depends more on the shape of the data than the raw quantities. 900 cups in 24 hours is one cup every 40 seconds or so, which isn't so bad, however I doubt that's the distribution of actual orders!
  
  I'm going to assume all of your 300 guests want to have a cup of coffee during a one-hour period. This works out as 5 coffees a minute, or one every 12 seconds.
  
  I'm ignoring factors of manpower, cost etc., and focussing on coffee preparation only :-)
  
  You can get 12-cup french press pots very easily, and probably larger ones. Assuming each one takes ~6 minutes to cycle (prepare, brew for 4 mins, serve, rinse), meaning you can serve 2 people a minute with one pot. 3 pots would allow you to serve 6 people a minute (amortised) and serve 300 people in an hour. A few more pots would make it very comfortable. Assuming you're grinding the coffee fresh, you'll get a far superior brew from this than perk coffee that's been sitting there for 20 minutes.
  
  So serving people fast enough shouldn't be too hard, but boiling water fast enough might be, and for that you just need an urn, with which you can keep a large enough supply of boiling water to just fill up and go.