Don't waste your time grilling roast beef. That is, of course, unless you do it correctly. If you grill the right type of roast with the correct grilling method, you'll be serving tender and juicy grilled beef...and everybody will be happy!
Grilling a roast that's not dry, chewy and flavorless depends on a few things. First, it's important to know your beef, and choose the correct cut that's suitable for grilling. Second, the beef roast needs to be grilled using the proper technique. Third, the beef needs to reach the correct done temperature. And last, the meat needs to rest before being served.
There are lots of different cuts of beef roast, with many being great for grilling, and many others that are not.
The roasts you don't want to cook on your grill include most of the chuck roasts, and some of the round roasts. These include the top blade roast, the 7 bone roast, the bottom chuck roast, the chuck shoulder roast, the eye of round, and the bottom round roasts.
You're better off barbecuing the chuck roasts at low temperatures for hours. They have quite a bit of tough connective tissue, and varying amounts of fat that make them unsuitable for grilling. The round roasts listed above respond better to moist heat cooking rather than grilling.
The following cuts of beef respond well to higher grilling temperatures, as long as they're not cooked to too high of an internal temperature.
Chuck eye, top round, rib roast and beef tenderloin are best when grilled first over direct heat then finished with indirect heat. The hot, direct grilling browns the surface a bit, creating some great flavor. The follow up cooking with indirect heat brings the internal temperature up to the target gradually.
Any large cut of meat, if cooked at too hot of a temperature, will be overdone around the outside, and under cooked in the center. Lower temperature cooking brings the meat to an even level of doneness throughout.
A general guideline that I follow is the more I spend for a beef roast, the lower its final internal temperature. More expensive cuts are usually better served rare to medium rare.
Tenderloins and rib roasts are definitely best when cooked to no more than a medium-rare. Once they reach medium, they're less juicy and tender.
The following table shows the final internal temperature of the grilled roast beef when it's at the different levels of doneness.
But for the roast to reach the desired temperature, the meat has to be removed from the grill when its internal temperature is from 5 to 10 degrees under the target. Read the next section for the explanation.
The last step, and probably the most important, is to allow the roast to rest after removing it from the grill. Two things happen during this resting period.
First, the temperature equalizes. The exterior of the meat is much hotter than the interior when it comes off the grill. The heat travels inward, literally cooking the meat to a higher temperature as it sits, covered lightly with foil, on the counter top. This is why you must remove meat from the heat source before it reaches the done temp you're shooting for.
Second, the meat fibers relax during the rest period, which allows the juices that have been squeezed out of the meat to be reabsorbed. If you cut the meat right after you take of off the grill, juice will run all over the place. If you wait for at least 20-30 minutes, most of the juices will be trapped inside the meat fibers, making the grilled beef much more juicy and tender.
When grilling roast beef, choose the right cut. Use the proper grilling method, be aware of internal meat temperature targets, and let that meat rest before serving.