Combine all of the marinade ingredients in a zip lock gallon freezer bag.
Close and shake to combine.
If you bought an "untrimmed tri-tip" than carefully remove most of the fat cap before cooking. Don't remove all of it or cut into the meat itself in the process of removing it.
Open bag and add tri-tip, closing carefully and removing as much air as possible.
Marinate for 4 hours.
Pre-heat grill to Medium heat, then place the tri-tip on the grill.
After 5 minutes, flip the tri-tip.
Check the meat every 10 minutes, watching the temperature.
Remove from grill when the meat reaches approximately 5 degrees from the desired temperature, making sure to get your readings from the thickest part of the meat. The meat will continue to rise in temperature for a few minutes even after being removed from heat.
Let the meat sit for about 10 minutes, then slice against the grain in thin slices.
Serve and enjoy!
Degree of Doneness for Beef: 125 F - Rare, cool red center 135 - Medium Rare, warm red center 145 - Medium, warm pink center 150 - Medium Well, slightly pink center - not recommended 160 - well done, little or no pink - not recommended