Agitation in French press extraction seems to be largely unexplored. We tried some serious agitation in the press this week, and enjoyed some very tasty results with our Koke. In addition to significantly increased extraction, the coffee tasted noticeably cleaner than even via the traditional Coffee Catcher method.
For the record, here's the process we used:
1. If you tend to use a finer French press grind, coarsen it up a few notches. On our Virtuosos, we found 27/26 led to over-extraction, and 31 was about right.
2. Use a half dose in an 8 or 12 cup press, in order to leave room for aggressive agitation.
3. Throw in a Coffee Catcher, pour and let brew stand for 3 minutes.
4. At 3:00, begin shaking the press vigorously in a consistent, circular motion. You should see a substantial whirlpool effect.
5. Shake continuously until about 3:45, and press at 4:00. Pour out right away.
So, would 4 minutes of continuous agitation inevitably over-extract? What about agitating during the first minute, instead of the final minute? There's room for more experiments here...