The Food Lab: 13 Rules For Perfect Prime Rib
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I admit that I'm often guilty of hyperbole and severe misusage of words, particularly when it comes to "perfect." Truth be told, there's no such thing as a perfect recipe, because if a truly perfect recipe did exist, then there'd be no reason to continue exploring and experimenting in the kitchen, which would mean that my mom was right and what the heck am I doing with my life?!
So when I use the word "perfect," what I really mean is, "I've given this issue a lot of thought and spent countless hours studying and testing it, and to the current best of my knowledge, this is the best method for getting from point A to point B with minimal fuss, but it may well turn out that in a few years, a few months, or maybe even a few days, I'll discover something that makes me change my mind about something that I was convinced of or at least fairly certain of or at least could make a good argument for in the past, so please take it with a grain of salt when I say that this is perfect."
In other words, any recipe writer (or scientist, for that matter), who is unwilling to go back on their word in the face of new evidence or better technique has already lost the long, hard battle towards beauty and truth.
And is there anything more truly beautiful than a perfect* prime rib? A deep brown crust crackling with salt and fat, sliced open to reveal a juicy pink center that extends from edge to edge, the faint but distinct funk of dry-aging permeating the room as it gets sliced. When you see such a roast in front of you, everything else—the argument over mashed potatoes you had with your sister, the red wine stain on the carpet, the enticingly crisp bowl of roast potatoes, even the plaintive look of the dogs staring up with a "please sir, can I have a bone?" face—disappears as your eyes, nose, and mind get lost in a mental vortex of fat and drippings.
*See two paragraphs above
Here now is a snapshot of the current state of "perfect" in my prime rib world. All materials are subject to change.
The Rules of the Roast
There's no need for me to go into major detail here—if you want to know everything there is to know about roast beef, check out my full primer here. Instead, I'll just sum up the findings of years of study, hundreds of pounds, and tens of thousands of calories worth of prime rib experiments in 14 easy-to-remember (or at least easy-to-print-out-and-tape-to-the-fridge) rules.
Rule #1: Choose Well-Marbled Meat
Marbling is the streaks of intramuscular fat that run through the meat. The more marbled your meat, the juicier, more flavorful, and tender it'll be. Buying "Prime" graded beef is a good guarantee of this fat content, though it's possible to find ungraded beef with plenty of marbling as well. If you're not the kind of person who likes fat in their beef, then prime rib is not for you. You might also may not be invited back to my home again.
Rule #2: Grass is for Funk, Grain is for Fat
Used to be that most 100% grass-fed beef was lean, lean, lean. These days, with more folks getting into the game, that's not always the case. But 100% grass-fed beef tends to be a little more grassy and funky in its flavor than grass-fed, grain-finished beef, which tends to be richer. For the record, all beef is raised primarily on grass. Grain-fed steer are only finished on grain for the last few months of their lives. (That is, if someone is selling you "grass-fed, grain-finished" beef, well, they're just selling you normal beef).
Rule #3: Choose the Oldest Beef You Can Afford
Dry-aging is a process by which large cuts of meat are held in a temperature and humidity-controlled room for several weeks. During this period, they lose moisture (concentrating their flavor), enzymes break down muscle matter (making the meat more tender), and bacteria will start to consume the exterior of the meat in a kind of controlled rot, which adds a flavorful, funky, almost blue cheese-like aroma to the meat. The outer layers are then carved off and discarded before being sold, leaving you with clean, flavorful, ulta-tender meat underneath. The process is not cheap, but in my opinion, the results are well worth the extra cost.
Rule #4: Dry-aged is better than wet-aged.
When buying aged beef, make sure that you are buying dry-aged beef. Wet-aging is a relatively recent practice in which beef is stored in a vacuum-sealed bag for a few days or weeks before being sold. While there are some very minor benefits to tenderness using this method, there are no flavor benefits whatsoever. Really, it's a way for unscrupulous meat sellers to charge higher prices for meat that was going to end up sitting in its plastic bag anyway.
Rule #5: Only Dry Age at home if you've got the proper resources
I've seen a copule sources recommend a form of pseudo dry-aging at home (that is, leaving pieces of meat loosely covered in your fridge for a few days or up to a week). Having thoroughly tested this method and having administered multiple blind taste tests with the results, I can confirm with multiple blind taste tests that the method absolutely does not work—at least, if true dry-aged flavor is what you're after. It will dessicate the exterior a bit, making for more efficient browning, but other than that there are precisely zero detectable flavor differences of texture differences between 1-week home "dry-aged" beef and completely fresh beef.
True dry-aging at home is possible, but it requires the right cut of meat and the right aging environment. Given the proper technique, it is possible to do at home. Check out our Complete Guide to Dry-Aging Beef at Home for more details.
Rule #6: Buy Bone-in Beef
While no actual flavor exchange takes place between the bones and the meat, there is an advantage to roasting a rib with the bone intact: insulation. Bones have a higher thermal resistance than meat, meaning the meat around the bones will cook slower than the rest of the roast, leaving those sections extra-tender and juicy. To make carving easier, you can remove the bones from the raw beef and tie them back on if you'd like. (Ask your butcher to do this for you.)
Rule #7: Season Well, and Season in Advance
For best results, salt your prime rib on all surfaces with kosher salt at least 45 minutes before you start cooking it, and preferably the day before, leaving it in the fridge uncovered overnight. Initially, the salt will draw out some moisture and end up dissolving in it. Over time, this salty liquid will dissolve some meat proteins (mainly myosin), loosening its structure, and allowing the salty juices to be re-absorbed into the meat. Your meat ends up better seasoned with less salty run-off.
Rule #8: Roast Low and Slow
The higher the temeprature you cook your meat at, the greater the temperature gradient within your meat will be, meaning by the time the center of your meat is a perfect medium-rare, the outer layers will be overcooked. You end up with a rosy red center, but dry, gray outer layers. Roasting at very low temperatures (around 200°F) will prevent this from happening.
Rule #9: Don't Worry About Browning Until the End
Many recipes will have you start your meat in a really hot oven or in a roasting pan on the stovetop to brown it before reducing the temperature to finish it off. In fact, the opposite method works better. Slow roast first, then brown at the very end. It allows you to brown faster, which means you end up with less overcooked meat in the layers below. The method also allows you to rest your meat prior to browning it, which means that as soon as your guests are ready to eat, you're ready to carve.
Rule #10: See Rule #11
Rule #11: Use a Thermometer!
Timing is at best a loose guide to when your meat will be ready. It can't take into account variables like oven cycles, fat content, convection patterns, or nosy relatives poking their face in the oven every few minutes. A thermometer is the only way to guarantee perfectly cooked meat, and a good instant read (like the Thermapen) is the best one for the job. Aim for 115 to 120°F for medium rare (125 to 130°F after resting), or 125 to 130°F for medium (135 to 140°F after resting). And remember, a roast will continue to rise by 5 to 10°F as it rests (see rule #13 below), so make sure to pull it out early to account for that!
Rule #12: Use an Instant Read Thermometer, not a Leave-in Thermometer.
Leave-in thermometers offer convenience, but they're inaccurate. The problem is that they're made of metal, which ends up conducting heat into the meat in the region around the thermometer. This leads to falsely high readings. In my testing, I found that a leave-in thermometer will register about 5 degrees higher then an instant-read thermometer inserted into a similar part of the roast. Moral: you can use the leave-in as a general guide and an early alarm, but make sure to double-check with your instant-read.
Rule #13: Let it Rest
Like all meat, resting is a way to improve juiciness and texture. As the meat cooks, the temperature gradient within the muscle tissue causes an imbalance in the distribution of juices within. Slicing a hot roast open directly out of the oven will result in juices spilling out all over the cutting board from areas in which the juice concentration is too high. Properly rested meat will retain all this juice as its sliced, delivering it to your mouth, not the trash.
What About the Sauce?
Since publishing this Perfect Prime Rib recipe, the most frequently asked question has been, "what about the jus?"
See, the great thing about that method is that it absolutely minimizes moisture loss within your meat. There are very few drippings into the bottom of the pan. A 10-pound roast will leave about this much:
This is good news for your beef—it means that rather than having its juices squeezed out into the pan, they're all trapped safely inside the meat, leading to juicier, tastier results. But there's one downside: without any flavorful drippings, there's no easy way to make a tasty just or gravy to drizzle over that meat, not to mention make your Yorkshire Puddings.
The easiest solution I've found? Use some extra beef. By searing off a few hunks of beef shin or oxtail in a Dutch oven, deglazing the drippings with wine and stock, adding some vegetables, then roasting the whole lot along with the prime rib in the same oven, you can build a powefully flavorful jus, with the added benefit of having a pile of fall-off-the-bone tender braised beef oxtails to serve alongside that roast dinner.
What's that? Too much beef for one holiday table you say? That's alright, you're not invited to my place either.
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About the author: J. Kenji Lopez-Alt is the Chief Creative Officer of Serious Eats where he likes to explore the science of home cooking in his weekly column The Food Lab. You can follow him at @thefoodlab on Twitter, or at The Food Lab on Facebook.