Coffee? Sauce? Heresy I say!
The amazing cut of tri tip deserves a simple rub of salt, pepper, garlic and a little parsley. Do yourself a favor and order some traditional tri tip seasoning from Suzie Q's in Santa Maria, CA. It's perfect and works awesome on lots of other dishes as well.
Grill all sides over oak to sear, slide to indirect and cook until 135 in the middle. Rest for 10 minutes in foil, slice against the grain and enjoy California's greatest contribution to American cuisine. Serve with ranch beans, fresh salad and grilled bread with butter for traditional CA style. If you must sauce your meat, it's tomato based salsa.