Many thanks to INIT_SIX for also pointing out a quick way to reduce the size of your WPA handshake captures using pyrit:
pyrit -r /path/to/capture.cap -o /path/to/handshake-only-output.cap strip
Add the “-e” or “-b” switches to filter down to just a single AP by ESSID or BSSID respectively:
pyrit -r capture.cap -o output.cap -b "99:88:77:66:55:44" strip
That’s it! Good hunting!