Begin by seasoning your tri-tip well on all sides. Focus on creating an even coating across the whole tri-tip.
Preheat your smoker to 225F (Optional add a piece of your favorite smoking wood). Place your meat inside the smoker, as far from the heat source as possible and smoke until the steak hits your desired doneness. For me this is usually about 125F-135F.
In a spritzer, mix vinegar and beef stock. Mid way through the cook and again right before you remove the tri-tip from the smoker, thoroughly spritz all sides of the tri-tip with the liquid.
Searing tri-tip steak is best done in a cast iron skillet or directly over the coals, but use whatever you have available. Preheat your cast iron or your fire and get it to sear temperature approximately 500F.
Place your steak on the heat and cook for about 1 minute on all sides, until you have developed a strong sear. Your steak is already cooked to the doneness you want, so all we are doing in this step is adding a crust.
Slice against the grain and serve immediately.