Concerning the Aging of Beef


The first official reports on the fact that meat becomes more tender when stored were Bouley (1874) and Lehman (1907). The breakdown of protein was first indicated by Hoagland et al in 1917. The process has been called ripening, aging or conditioning. (Toldra, 2010)

Boxed beef was introduced in the USA in the 1950’s and 60’s for hotels and restaurants who could not buy in beef sides. When supermarkets demanded the same service, Iowa Beef Processors was founded in the 1970’s specifically to provide this. It was believed that the days of dry aging of beef were over. The process of hermetically sealing meat in polyethylene bags was developed by Cryovac. (Rice, 1997)

And excellent article from The Food Lab reviews home aging and the basis of butchery aging of beef. Here are the bullet points of a great article:

The Purpose Of Aging

In order to improve texture and flavour, the following is achieved:

– Moisture loss where up 30% of its initial volume due to water loss.

– Tenderization through enzymes naturally present in the meat which act to break down some of the tougher muscle fibers and connective tissues. A well-aged steak should be noticeably more tender than a fresh steak.

– Flavor change is caused by numerous processes, including enzymatic and bacterial action, along with the oxidation of fat and other fat-like molecules. Properly dry-aged meat will develop deeply beefy, nutty, and almost cheese-like aromas. (Foodlab)

Is aged meat really better than fresh meat?

A panel of tasters tested meat aged to various degrees and rank them by overall preference, tenderness, and funkiness. Almost everybody who tasted meat that had been aged for a couple of weeks—the period after which some degree of tenderization has occurred, but seriously funky flavor has yet to develop—preferred it to completely fresh meat. (Foodlab)

On the other hand, folks were more mixed about meat aged longer than that. Many preferred the more complex, cheese-like flavors that developed with meat aged between 30 and 45 days. Some even liked the ultra-funky flavors that developed in 45- to 60-day-old meat. Where you lie on that spectrum is a matter of taste. (Foodlab)

Selecting Meat to Age

Choose a large piece that is best cooked with quick cooking methods. This makes the standard steakhouse cuts—the New York strip, the rib steak, and the porterhouse—the ideal cuts for aging. the easiest to find is rib steak, which is what you get when you cut a prime rib between the bone into individual steaks. (Foodlab)

Dont try and age individual steaks. The straks beximes so dried out as to be completely inedible. After trimming away the desiccated and slightly moldy bits (perfectly normal for dry-aged meat), one is left with a sliver of meat about a half centimeter thick. It was impossible to cook to anything lower than well-done, making my effective yield a big fat zero. Dry aging is done with large cuts. (Foodlab)

The FoodLab tested large cuts in 4 def C temp, with air circulation achieved with a small fan. Humidity was left untouched which fluctuated between 80% at the start and 30% later in the process. (Foodlab)

The more protection you have for the meat from the extetior, the better your final yield. When you dry-age meat for any length of time that’s enough to make a difference, the exterior layers get completely desiccated and must be trimmed away. The less protected the “good” meat, the more of it you’ll throw in the trash and waste. (Foodlab)

Such protection can be by leaving the fat cap on. The fat cap effectively guards the meat against moisture loss, leaving us with a spinalis muscle that is 100% edible. The yield you get amounts to basically the equivalent of a completely normal-sized roast. If you imagine your prime rib as a long cylinder, the only meat you actually end up losing is from either end. The fat cap and bones will completely protect the sides. (Foodlab)

Jess Pryles adds the following wisdom: Overall, a number of factors determine how significantly meat will benefit from aging. Lower grades actually get more out of it, so a Select graded cut will respond better than a Choice graded cut, because there’s more room for improvement. Although a certain amount of aging does ultimately help all beef, some muscles respond better than others; so the eye part of your ribeye (Longissimum dorsi) will have a higher tenderness response than the cap on your ribeye (Spinalis dorsi), even though you’ll be buying them together as one steak. And have you ever noticed it’s only beef that gets aged? Well, out of all the commercial consumer proteins, beef is the most variable in terms of tenderness. Generally, pork, lamb and veal are tender enough to begin with, it’s just poor cooking skills that can make them tough. (Jess Pryles) The relative young age of these animals, compared to beef, further leads to generally more tender pork and lamb.

What Causes Flavor Change?

If you dry-age an untrimmed, bone-in, fat-cap-intact prime rib, you’ll end up losing about 30% of its total weight over the course of 21 to 30 days or so. The weight is almost exclusively lost from the outer layers—that is, the portion of the meat that is going to be trimmed off anyway, regardless of whether it’s aged or not. The fact is, with the exception of the cut faces that need to be trimmed off, the edible portion of an aged prime rib is pretty much identical to that of a fresh prime rib. (Foodlab)

Flavour is not “concentrated.” A trimmed steak cut from an aged piece of beef is pretty much the exact same size as a trimmed steak cut from a fresh piece of beef. (Foodlab)

The Food Lab measured the density of beef aged to various degrees against that of completely fresh meat. He cut out chunks of meat of identical weights from the centers of ribeyes aged to various degrees, making sure to exclude any large swaths of fat. He then submerged each of these chunks of meat in water and measured their displacement. What was found was that meat aged to 21 days displaced about 4% less liquid than completely fresh meat. A slight increase, but not much. Meat aged all the way to 60 days displaced a total of 5% less—showing that the vast majority of moisture loss occurs in the first three weeks. (Foodlab)

Once the meat was cooked, these differences in density completely disappeared. That is, the less aged the meat was, the more moisture it expelled. (Foodlab)

One of the side effects of aging is the breakdown of meat protein and connective tissue. This makes the meat more tender, as well as causing it to contract less as it cooks. Less contraction = less moisture loss. (Foodlab)

When all was said and done, in many cases, the meat that was 100% fresh ended up losing even more liquid than the dry-aged meat. (Foodlab)

Meat dry-aged for 21 days (the period during which the largest change in density of the internal meat occurs) was indistinguishable from fresh meat in terms of flavor. The improvements were in texture alone. It wasn’t until between the 30- and 60-day marks that real, noticeable changes in flavor occurred, and during that time period, there was essentially no change in internal density. Thus, moisture loss is not tied to flavor change. (Foodlab)

Why does meat that’s being aged stop losing moisture after the first few weeks?

It’s a matter of permeability. As meat loses moisture, its muscle fibers get more and more closely packed, making it more and more difficult for moisture under the surface to continue escaping. After the first few weeks, the outer layer of meat is so tight and tough that it is virtually impermeable to moisture loss. (Foodlab)

If it’s not moisture loss, what factors do affect the flavor of aged beef?

A couple of things. The first is enzymatic breakdown of muscle proteins into shorter fragments, which alters their flavor in desirable ways. But this effect is completely secondary to the far more important change that occurs when fat is exposed to oxygen. It’s the oxidation of fat, as well as bacterial action on the surfaces of the meat, that causes the most profound flavor change—the funkiness you get in meat that has been aged for over 30 days. (Foodlab)

It’s true that much of this funky flavor is concentrated on the outermost portions of the meat—the parts that largely get trimmed away—and, for this reason, if you want to get the most out of your aged meat, it’s vitally important that you serve it with the bone attached. Unlike the fat cap, which is completely removed and discarded, the outer areas of bones will still house tons of oxidized fat and affected meat. The aromas from this meat reach your nose as you’re eating, altering your entire experience. Lovers of aged steak also prize the spinalis (again, that’s the outer cap of meat on a ribeye) for its richer, more highly aged flavor. (Foodlab)

Aging Setup

It’s very simple and requires virtually no special equipment. There are just a few things you’ll need:

– Fridge space. The best thing you can use is a dedicated mini fridge, one that you can keep closed so that the meat smells don’t permeate the rest of your food, and vice versa. Aged meat can pick up aromas from your refrigerator. Unless your refrigerator is odor-free, a mini fridge is the best possible option. (Foodlab)

– A fan. To promote drying of the surface and even aging, you want a fan inside your fridge to keep air circulating. This works in much the same way as a convection oven, promoting more even cooling and humidity all around. I used a standard desk fan. In order to get it in there, I cut a small notch in the seal for the fridge door—just large enough for the cord to fit through. (Foodlab)

– A rack. Your meat must be elevated on a rack. I tried aging a piece of meat on a plate and directly on the floor of the fridge. It did not work. The part in contact with the plate didn’t dehydrate properly and ended up rotting. Aging on a wire rack, or directly on the wire shelf of a fridge, is the way to go. (Foodlab)

– Wrapping seems to be one of those controversies which experience should settle. Some authors and “aging experts” insist to wrap the roast loosely in a triple layer of cheesecloth. After the first day, carefully unwrap and then rewrap with the same cheesecloth to keep the cloth fibers from sticking to the meat. (Fine Cooking).

– Time. You will be rewarded with the steak of your dreams for your patience. (Foodlab)

It was found that humidity plaid a minimal role in aging. After the first couple of weeks, the outer layers of the beef become all but impervious to moisture. It really doesn’t make much difference how humid or dry the environment is; the internal meat is protected.


Blind tests results showed that aging time was largely a matter of personal preference, but here’s a rough guide to what happens over the course of 60 days:

– 14 days or less: Not much point. No change in flavor; very little detectable change in tenderness. Very few people preferred this steak. (Foodlab)

– 14 to 28 days: The steak starts to get noticeably more tender, particularly toward the higher end of this scale. Still no major changes in flavor. This is about the age of a steak at your average high-end steakhouse. (Foodlab)

– 28 to 45 days: Some real funkiness starts to manifest itself. At 45 days, there are distinct notes of blue or cheddar cheese, and the meat is considerably moister and juicier.
Most tasters preferred 45-day-aged steak to all others. (Foodlab)

– 45 to 60 days: Extremely intense flavors emerge. A handful of tasters enjoyed the richness of this highly aged meat, though some found it a little too much to handle for more than a bite or two. One expert said of the 60-day steak, “I may have hit my aging threshold.” It is rare to find any restaurant serving a steak this well-aged.” (Foodlab)

What about wet-aging? What is it, and does it work?

Wet aging is simple: Put your beef in a Cryovac bag, and let it sit on the shelf (or, more likely, on refrigerated trucks as it gets shipped across the country) for a few weeks. Tell your customers that it’s aged; sell it at a premium. (Foodlab)

The problem is that wet-aging is nothing like dry-aging. For starters, there is no oxidation of fat in wet aging, which means that there is no development of funky flavors. A minimal amount of flavor change will occur through enzymatic reactions, but they are, well, minimal. Additionally, wet-aging prevents the drainage of excess serum and meat juices. Tasters often report that wet-aged meat tastes “sour” or “serum-y.” (Foodlab)

Wet-aging can offer the same tenderizing and moisture-retaining benefits as dry-aging, but that’s about it. In reality, wet-aging is a product of laziness and money-grubbing. It’s easy to let that Cryovacked bag of beef from the distributor sit around for a week before the bag is opened, allowing it to be called “aged” and sold for a higher price. I don’t buy it. When you are being sold “aged” meat, be sure to ask whether it’s been dry-aged or wet-aged. If they don’t know the answer or are unwilling to share, it’s best to assume the worst. (Foodlab)

The other drawback to wet-aging: It can’t be carried out for as long as dry-aging. It seems counterintuitive, considering that a wet-aged hunk of meat is largely protected by the outside environment. But if even a smidge of harmful anaerobic bacteria makes its way into that bag, the meat will rot inside its cover, giving no indication that it’s done so until you open it up. (Foodlab)

What about those fancy “dry-aging bags”?

Like me, you must have seen those dry-aging bag videos kicking around the internet. The idea is that you seal a cut of beef in some sort of special bag that allows you to safely age it at home. Supposedly, it aids in aging by allowing moisture out, but letting no air in. (Foodlab)

I ordered a few kits to test this out myself. Before I even began aging, there were problems. I went through an entire $25.50 kit’s worth of three bags, none of which were able to form a tight seal using my standard FoodSaver vacuum sealer (and yes, I followed the directions to a T). After ordering one more kit (spending a total of $51 on this), I finally got a single bag to seal, only to discover the next day that it in fact was not sealed properly and had leaked:

I decided to let it go anyway, pressing out as much air as possible and trying to ensure good contact between the bag and the surface of the meat, as the instructions recommended. (Foodlab)

After aging it for several weeks, I unwrapped the roast and found this:

Not the most promising sight, but I dutifully trimmed away the molded areas, trimmed down the roast, and cut steaks from it. The taste tests I performed showed no significant difference between steak aged in one of these bags and steak aged in the open air. Where I did feel a difference was in my wallet, which was now $51 lighter than it was when I started. (Foodlab)


The following are great aging innovations:


A Cryovac executive once said that “Its what you’re use to that tastes best and fewer and fewer Americans have an opportunity to become used to dry-aged beef.” (Rice, 1997) That may be true and is particularly true in the meat industry. The experience of eating dry aged beef is, however, so much richer, and tastier than fresh or wet aged beef, that it will always have its place in fine restaurants and homes of meat lovers.


Fine Cooking, Article by Jennifer Armentrout.


Rice, W. 1997. The Steak Lover’s Cookbook. M Kathryn Thompson.

Toldra, F. (Editor) 2010. Handbook of Meat Processing. Blackwell Publishing.

Jess Pryles

Photo Credit: Jess Pryles