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The Food Lab's Complete Guide to Dry-Aging Beef at Home

[Photographs: J. Kenji Lopez-Alt]

It's time for another round of The Food Lab. Got a suggestion for an upcoming topic? Email Kenji here, and he'll do his best to answer your queries in a future post. Become a fan of The Food Lab on Facebook or follow it on Twitter for play-by-plays on future kitchen tests and recipe experiments.

Sometimes I get emails from readers that say something along the lines of, "you said in article X one thing, then a couple years later in article Y, you said almost the complete opposite. What gives? Don't you believe in science, and doesn't science deal in facts?"

There's only one kind of science that isn't open to contradicting itself: the bad kind. Science needs to be open to accepting and considering contradictory evidence and redefining "facts" by definition. Heck, if new theories weren't allowed to be formed and conclusions debunked with further experimentation, we'd still believe in crazy things like spontaneous generation, static universes, or even that searing meat seals in juices. And then where would we be today?

I bring this up because a few weeks back, I went through great pains to test and explain precisely why you cannot dry-age meat at home, no way, no how. Today, I'm going to explain to you exactly how you can dry-age at home, how relatively simple it is, and how it can vastly improve the eating quality of your steaks and roasts until they are better than what you can buy at even the best gourmet supermarket*.

*And unlike many other places that claim similar results, I actually have the blind taste tests to prove it!

Now before you go and call up the National Committee of Good Science and send them to confiscate my calculator (by which I mean my head) let me first explain that I stand by 100% of what I wrote in that article: Given that you are starting with individual steaks, dry-aging at home is not feasible, despite what some otherwise reputable source have said in the past. Blind tasting showed that between the first day and the seventh day of such aging, there was absolutely zero perceptible improvement in the eating quality of the steaks.

But we all know that individual steaks is not how meat is dry-aged by professionals, right? No, they start with whole sub-primals—large cuts of meat with bones and fat caps fully intact, aging them uncovered in temperature, humidity, and air speed-controlled rooms designed to allow them to age for weeks or months without rotting. The question is, can we do this ourselves at home?

I got my hands on 80 pounds of Prime Grade bone-in, fat-cap intact beef ribs to get my answers*. Over the course of over two months, I aged them in close to a dozen different ways in order to determine what works, what doesn't, and what matters. Here's what I found.

*Special thanks to Pat LaFrieda Meat Purveyors for donating much of the fine beef used for this testing.

The Purpose of Aging


How does aging work?

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Good question! First, a brief rundown on why you might want to age meat. Conventional wisdom sites three specific goals to dry-aging meat, all of which contribute towards improving its flavor or texture.


But is aged meat really better than fresh meat?

It depends. I had a panel of tasters test meat aged to various degrees and rank them in overall preference, tenderness, and funkiness. Almost everybody who tasted meat that's 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.

On the other hand, folks were more mixed about meat aged longer than that. Many prefer the more complex, cheese-like flavors that develop with meat aged between 30 to 45 days. Some even liked the ultra-funky flavors developed in 45 to 60-day meat. Where you lie on that spectrum is a matter of experience. I personally prefer meat aged to 60 days, though beyond that it gets a little too strong for me.


Ok, I'm sold. Why would I possibly want to do it at home when I can order it online or from my butcher?

Two reasons. First, bragging rights. How awesome is that dinner party where you tell your friends, "like this beef? I aged it for 8 weeks myself," gonna be?

Second, it saves you money. Lots of money. Aging meat takes time and space, and time and space cost money. This cost gets passed on to the consumer. Well-aged meat can cost anywhere from 50% to 100% more than an equivalent piece of fresh meat. At home, so long as you are willing to give up a corner of your fridge or you have an extra mini-fridge, the extra costs are minimal.

You may have read that in addition to the time and space required, much of the cost of aged meat comes down to the amount of meat that is wasted—that is, meat that dries out and needs to be trimmed. This is not as big a factor as you'd think, and we'll find out why soon.

Selecting Meat To Age


What cut of meat should I buy for aging?

To age meat properly, you need to 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. (See here for for more on the 4 high-end steaks you should know). The easiest to find whole (and my personal favorite) is the rib steak, which is what you get when you cut a prime rib into individual steaks between the bone.


What's the minimum size I'll need to buy for proper aging? Can I age an individual steak?

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Individually "aged" steak on the left, fresh steak on the right.

Nope, unfortunately you can't age an individual steak. (See here for more details as to why not). You can wrap them in cheesecloth or paper towels, set them on a rack, and leave them in the fridge for about a week, but during that time, no detectable amount of texture or flavor changes will develop. Try and age them even longer, and (assuming they didn't start rotting*) here's what you get:

*In my experience, this can happen when the cheesecloth or paper towel holds moisture against the meat and you don't have enough ventilation.

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45-day individually dry-aged rib steak

The meat is so dried out as to be completely inedible. After trimming away the desiccated and slightly moldy bits (perfectly normal for dry-aged meat), I was 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.

The simple truth is that in order to dry-age, you need larger cuts of meat, and you need to age them in open air.


So of the larger cuts of meat, what should I look for?

Rib sections come in several different forms, each with their own number designation.

I aged a 107, a 109A, and a 109 Export in a mini-fridge (this one from Avanti) set at 40°F in which I placed a small desk fan in order to allow air to circulate (I had to cut a small notch in the sealing strip around the door to allow the fan's cord to pass through), simulating a dry-aging room on a small scale. I made no attempt to regulate humidity, and it bounced around between 30 and 80% humidity (higher at the beginning, lower as the aging progressed).

I found that the more protection you have, the better your final yield. Why does protection from the exterior matter when aging meat? It's because when you dry age meat for any length of time long 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. Here's what happens when you try and age a 109 Export:

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See how much of that poor Spinalis* muscle has withered away and dried? I had to completely remove it before I found meat that I was able to cook underneath. And that is not meat you want to waste.

*The spinalis, also called the ribeye cap is the tastiest cut on the cow!

On the other hand, here's what you're left with after removing the fat cap on a 109A:

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The fat cap effectively guards the meat against moisture loss, leaving us with a Spinalis muscle that is 100% edible.

Trim off the fat a bit more as well as the cut faces, and here's what we've got:

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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.

What Causes Flavor Change?


So really, aged meat doesn't lose much moisture. But wait a minute, haven't I read that aged steaks can lose up to 30% of their weight in water? Isn't that one of the reasons why aged steak is so expensive?

Don't believe everything you read. That 30% figure is deceptive at best and an outright lie at worst. Yes it's true that if you dry age an un-trimmed, bone-on, 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. What they don't tell you is that 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 is aged or not.

Has it never struck you as not just a little bit odd that the aged ribeye steaks in the butcher's display aren't 30% smaller than the fresh ribeyes in the display? Or that aged bone-in steaks are not stretching and pulling away from their bones (I mean, surely the bones aren't shrinking as well, are they?)

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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.


Ok, let's say I'm convinced about that. Does that mean that the whole idea that "meat flavor is concentrated" in an aged steak because of dehydration is also false?

I'm afraid so. It's a great idea in theory, but several facts don't support it.

First, there's simple visual inspection: 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.

Next, I measured the density of beef aged to various degrees against completely fresh meat. To do this, I 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. I then submerged each of these chunks of meat in water and measured their displacement. What I 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.

What's more, once the meat was cooked, these differences in density completely disappeared. That is, the less aged the meat was, the more moisture it expelled. Why is this? 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.

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

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Finally. A simple taste test was the nail in the coffin: Meat dry-aged to 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. 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.


So why does meat 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.

Take a look here:

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You can see that the layer of dried meat in a 4-week aged piece of beef is as thick as one aged for over 8 weeks. No matter how long I aged the steak, the waste was about the same—just about a centimeter from the exterior cut faces.


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 cause the most profound flavor change—the funkiness you get in meat that has been aged for over 30 days.

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 gets completely removed and discarded, the outer areas of bones will still house tons of oxidized fat and affected meat. The aromas from this meat reaches your nose as you're eating, altering your entire experience. Lovers of aged steak also prize the spinalis—the outer cap of meat on a ribeye—for its richer, more highly aged flavor.

Aging Set-up


What sort of set-up do I really need for aging steak at home? How simple is it?

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