How to reverse sear a steak

Here's a couple of hints:

1. Learn to judge doneness by feel. See this answer for a good guide to temp by feel.

2. Learn to judge grill temp by hand. Hold your hand palm down about 3-4 inches above the grill. If you can hold it there for a second or two, it's hot; 3-4 seconds is medium; 5-6 seconds is low.

3. Sear first. Start with a very hot grill. You want about two minutes per side. Do not move the steak while it is searing. Make sure you've given the grill grate at least 5 mins to heat up.

4. Use a two level fire. Once you've seared your steak, you want to finish cooking over a lower heat. Build a two level fire by putting the coals on one side of the grill rather than the whole thing. Then sear over the coals. Then move it to the other side to finish. If the grill isn't wide enough for a two level fire, you could try quenching the fire by cutting off air flow. That will cool it quickly.

5. Finish with the lid on. This helps cook by heating the air rather than just using direct heat.

6. Change your fuel. Stop using lighter fluid. Use a chimney instead. Hard lump charcoal is better than briquettes. It's easier to light, creates less left over, and burns hotter.

7. Rest your meat for a few minutes before eating. Be aware that it will continue to cook during this time, so you want to pull it off a little early.

8. Read up on cooking steak. There are a bunch of good questions on this site!

Pretty much...yes, but you can fix it!.

When you properly sous vide or very slow cook anything, you'll retain more of the myoglobin color because of the even cooking that often doesn't go above 140 at all. So a properly cooked steak like this will retain much more of its red colored myoglobin. Simply put, the meat will have more red juices to release! (Its a great, great thing about sous vide.)

As @Ronald mentions, the other thing is the resting of the meat. It's an important step as the muscle fibers relax after the heat is off and hold juices better then. An often misstep for the home cook is they allow a hot piece of meat to rest on a flat, solid surface. This causes the bottom of the meat to steam against the board, open the fibers in the meat more, and release the juices on to the board. Rest your meat on a raised baking rack so that it has air circulation all around it.

After a short rest - for most steak 10 minutes is fine, then you can cut into the steak. Use a very sharp knife to slice. The meat here is essentially a sponge and you don't want to compress it and squeeze out the juices. A dull knife will do this and you'll lose more juice on the cutting board again. Use a sharp knife and apply steady, even, but light pressure while slicing - let the edge do the work (if it won't, sharpen the knife more).