Classic Meatloaf (The Food Lab)

Here's another recipe excerpted from my book, The Food Lab: Better Home Cooking Through Science. I hope you enjoy it.

In his 1958 classic, 365 Ways to Cook Hamburger (at least, it should've been a classic), along with hundreds of recipes for burgers, sauces, soups, meatballs, and casseroles, Doyne Nickerson offers no fewer than 70 recipes for meatloaf. 70! A different loaf every night for over two months! 10 loaves apiece for every man, woman, and child on the cast of Full House! (Another classic.) Amongst this litany are such colorful offerings as Chili Hot Top Meatloaf (it's flipped upside down and glazed with Heinz Chili Sauce), Sunshine Meatloaf (that'd be a loaf topped with ketchup-filled peach halves), and two—count 'em, two—variations on Banana Meatloaf (one with green bananas mashed into the meat, the other topped with bacon and ripe banana).

With such a varied and prolific precedent set, you may be disappointed to find out that I offer but a single, lonely recipe for plain old all-American meatloaf and not even one recipe that combines ground beef with bananas. But while Nickerson is unparalleled in his prolificacy, I plan on besting him in thoroughness.

You see, Americans are proud of their meatloaf, and rightfully so. It's one of our national dishes and deserves a place up on the pedestal, rubbing shoulders with the likes of hamburgers, barbecue, and hot dogs. I mean, it's a loaf made out of meat. What could be more decadent-yet-comforting than that?

The very best meatloaf should be tender and moist, with a distinctly soft but never mushy texture. "Velvety" and "rich" should come to mind when tasting it, tender enough to slice with a fork but firm enough to pick up that bite without it breaking. It should be a sponge for moisture, oozing juices when you eat it but not leaving a puddle on your plate. It should be deeply rich and meaty in flavor and savory, with just a hint of vegetable undertones to complement and lighten the slice. But make no mistake: meatloaf is about the meat. And, of course, it needs to reheat well for sandwiches.

We already know quite a bit about how ground meat behaves from our adventures with sausage, and we've learned the benefits of grinding your own meat (or, at the very least, having it ground fresh at the butcher). From those starting blocks, arriving at perfect meatloaf is just a short skip and a jump away.

Meaty Matters: What Different Types of Meat Bring to Meatloaf

Let's start with the very basics. Anyone who's been to a supermarket has seen those plastic wrapped trays labeled "meatloaf mix," which contain a combination of pork, beef, and veal. Why the mix? What does each of these meats bring to the table? To find out, I made several identical meat loaves using a very simple mix of meat and a few sautéed vegetables (carrots, onions, celery). Each loaf was cooked in a vacuum-sealed plastic bag in a water bath set at precisely 145°F. That way, I was certain that each batch was cooked identically. For my first test, I cooked three loaves: 100% beef, 100% pork, and 100% veal.

After more tastings, including an exclusionary test (beef and pork alone, beef and veal alone, and pork and veal alone), and combining all three, a few things became obvious. Pure beef cooked in meatloaf form loses quite a bit of moisture and acquires a coarse, gritty texture and slightly livery flavor. Pork has a much milder flavor and more fattiness, with a less coarse, softer texture. Compared to beef and pork, veal loses very little moisture at all, and it has a tender, almost gelatinous texture when cooked. However, it's completely lacking in flavor. Why do three different meats cooked in the same manner return such different results?

Well, pigs and cattle differ mostly in their fast-twitch versus slow-twitch muscles. Cows are large animals that spend most of their time walking around and grazing, requiring plenty of long, sustained effort from their muscles, which eventually turns them coarse, and flavorful, with a deep red color—a by-product of the oxygenation necessary for them to perform work.

Pigs are smaller and less active for sustained periods of time. You may see them trot over to the trough to gorge, but they spend the bulk of their time lying in the mud or in the shade to keep cool. Consequently, their dark slow-twitch muscles are less developed. Instead, you'll find plenty of paler, more fine-textured fast-twitch muscle, as well as a good deal of stored fat. Pork fat is also softer than beef fat, making it more pleasant to eat at normal serving temperatures. So, by combining beef and pork, you end up with a mix that has the great flavor of beef but an improved texture and softer fat from the pork.

Then what does veal bring to the mix?

The difference between veal and beef is a little more subtle, having to do with the age of the animal. When a cow (or almost any mammal, for that matter) is born, its muscles are not very well developed. Its fat is soft and malleable, its muscles pale and mild-flavored, with a high proportion of soluble collagen, the connective protein that transforms into gelatin as it cooks. It's the underdeveloped musculature that gives veal its tenderness, but it's the gelatin that lends ground veal its ability to retain moisture. How does this work? It helps to think of gelatin molecules as individual links in a very fine wire mesh and individual molecules of water as tiny water balloons. As the collagen is converted to gelatin inside a meatloaf as it cooks, these molecules of gelatin gradually link up with each other, forming a net that traps water molecules, preventing them from escaping. It's this same quality of gelatin that allows you to turn several cups worth of water into a quivering Jell-O mold with just a few tablespoons of powdered gelatin.

Thus the mix. Beef provides robust flavor, pork provides a good amount of tender fat, and veal provides plenty of gelatin to help retain moisture: The mixture provides the optimum balance of flavor, texture, fat content, and moisture-retaining ability. Or does it?

Say No to Veal, and What to Use Instead

Here's the problem with veal: It doesn't taste like much.

Sure, it adds gelatin to the mix, but it dilutes the meaty flavor at the same time. It can also be a bit of a pain to seek out (I have to travel all the way to the supermarket by my mom's apartment to get it, which means I've got to visit my mother every time I want veal; this can be problematic). I'd seen a few recipes that suggested replacing the veal with powdered gelatin*—an ingredient I always keep in my pantry. I made a couple loaves side by side, one with an equal mix of ground chuck, ground pork, and ground veal, and the second one with a mix of ground chuck, ground pork, and a couple tablespoons of unflavored gelatin hydrated in a bit of chicken stock and cooked until dissolved (I made sure to add the same amount of chicken stock to the first loaf as well). Texture-wise, both loaves proved to be moist and tender. Flavor-wise, the no-veal loaf had a clear advantage.

Gelatin it is.

*Since publishing this piece, I've been informed that the first instance of using gelatin in meatloaf as a means of helping retain moisture was in David Pazmiño's recipe for Glazed All-Beef Meatloaf recipe, a recipe he developed for Cook's Illustrated in their January 2006 issue. A shout out to him for the fantastic idea. It has helped meatloaves and meatballs around the world immeasurably since then.

Meatloaf Binders and Extenders

So, up to now, what we've essentially got is something that's halfway between a burger and a sausage. It's got the basic fat content of a burger, with the key difference being that the salt is mixed right into the meat rather than just seasoning the exterior. We all know what happens when you add salt to meat before mixing it, right? It causes the meat to become sticky and bind with itself as the salt slowly dissolves muscle proteins. But this is not a good thing for meatloaf, where tenderness and a loose, velvety texture are desired above all. We can mitigate those effects by adding the salt immediately before mixing and only mixing as much as necessary, but there are better ways to improve texture—namely, with binders and additives. Let's look at the most common ones to determine what role they play.

Eggs Add Structure

Eggs are an ingredient in nearly every meatloaf, and they have two distinct roles. Egg yolks, which are mostly water but contain a good amount of protein and fat, add flavor, richness, and moisture. They also help bind the meat together and get the loaf to set in a stable form without the need to overwork the meat. Egg whites have even more water in them, are devoid of any fat at all, and have a very mild flavor. Their main role is to add extra loose proteins to the mix to assist the egg yolks in their quest to add structure without overworking the meat or adding toughness. We'll definitely include them.

Dairy Keeps Meatloaf Moist

Milk and other dairy products, like heavy cream and buttermilk, contain both water and fat, adding two types of moisture to our meatloaf. There's a long-held theory that milk can tenderize ground meat, and this is the reason often cited for cooking ground meat in milk to make a Bolognese-style ragù. I'm pretty skeptical about this. Milk is mainly water, with some milk fat and a few proteins thrown in. What could cause it to tenderize meat?

Some sources claim that adding milk limits the cooking temperature to 212°F (the temperature at which water boils), which keeps meat from overcooking. What? Limiting temperature to 212°F? What good does that do? Meat toughens at temperatures a good 70 to 75°F below this threshold. Besides, plain old water (which is abundant in the meat and all the vegetables you add to meatloaf) will perform that function just as well. Indeed, cooking three batches of meat side by side, one simmered in milk, one simmered in water, and one allowed to simmer in its own juices, left me with three batches of meat that were equally tough. Fact of the matter is, milk does not tenderize meat. The only way to guarantee tender meat is not to overcook it. And that's a simple matter of using a thermometer when you bake the meatloaf.

Milk does, on the other hand, add moisture and fat and is worth including for that fact alone. Heavy cream works better. Better still is buttermilk, which has a unique tang that adds depth and complexity to the finished dish.

Breadcrumbs Keep Meatloaf Tender

Bread crumbs may, at first glance, seem like an unnecessary extender—something added just to stretch your meat a little bit further—but they are perhaps the most important ingredient of all when it comes to improving the texture of a meatloaf. Aside from absorbing and retaining some moisture as the meatloaf cooks, they physically impede the meat proteins from rubbing up too closely to one another, minimizing the amount of cross-linkage and thus dramatically increasing tenderness. In many ways, the physical structure of a meatloaf is much like the structure of an emulsified sauce stabilized with starch. In the latter case, starch acts like a bouncer, keeping fats from coalescing, while in the former, bread crumbs do the job, keeping meat proteins apart. I found that using crumbs from fresh bread slices ground in the food processor provided better moisture and binding capabilities than dried bread crumbs.

Mushrooms Act Like Breadcrumbs

Finally, mushrooms, while not necessarily a standard meatloaf ingredient, are an invaluable addition. Why do I include them under binders and extenders rather than lump them in with the aromatics? Because they act much more like bread crumbs than they do like, say, onions. Mushrooms are extremely porous and are full of flavorful liquid.

At the same time, they are soft and spongy. Just like bread crumbs, they prevent the meat proteins from interlocking, increasing tenderness while simultaneously adding flavor as they slowly release their liquid. In fact, they're so much like bread that I treat them exactly the same way—grind them in the food processor and add them to the raw mix, no parcooking necessary at all!

So, to summarize, we have the following chart:

The Key to Great Flavor: A Concentrated Flavor Base

With the meat mix and the texture of the loaf squared away, I shifted my focus to flavorings.

The base of carrots, onions, and celery made sense to me—the three vegetables are a classic addition to meat dishes and sauces for a reason—but when they are simply diced and added to the meat mix, their texture doesn't quite work in meatloaf; I found it interfered with the velvety-ness I desired. How to deal with this? Easy, just chop them finer and soften them. I used the food processor (already on my countertop to make the bread crumbs and chop mushrooms) to chop them into small pieces before sautéing them in butter until tender, adding a touch of garlic and Spanish paprika as well.

We've got the vegetables in there, now for a few ingredients to up the meaty backbone of the loaf, namely deploying my trusty umami bombs: anchovies, Marmite, and soy sauce. All three of these ingredients are rich in glutamates and inosinates, chemical compounds that trigger signals that tell our brains we're eating something savory and meaty. They make the meatloaf taste meatier without imparting a distinct flavor of their own. After sautéing all the ingredients for my flavor base together—the vegetables and the umami bombs—I added some chicken stock and buttermilk, along with softened gelatin, and reduced to a concentrated liquid simply bursting with flavor.

Mixing this flavor base into my meat produced a mixture wetter than any other meatloaf mix I'd seen. This led to a moister end product (that retained moisture with the help of the gelatin), but it proved problematic when shaping the loaf. I could bake it in a loaf pan, but I prefer making free form loaves on a baking sheet to maximize surface area for flavorful browning or glazing. The solution was to use a hybrid method. I packed my meatloaf mix into a loaf pan, covered it with foil, and then inverted the whole thing onto a rimmed baking sheet, spreading out the foil so that I now had a foil-lined baking sheet with an inverted meatloaf and loaf pan on top of it. I baked this way for about half an hour—just long enough to set its shape—and then used a spatula and kitchen towels to lift off the pan. The result was a perfectly loaf-shaped meatloaf (just right for slicing into sandwiches), with all the advantages of a free-form loaf and its extra surface area.

You can leave your meatloaf completely undressed, but I kind of like the old-fashioned, low-brow sweet vinegariness of a ketchup-and-brown-sugar glaze. Draping the loaf in bacon wouldn't do any harm either. I still haven't tried topping my loaf with bananas as Mr. Nickerson so helpfully suggested.

As he could tell you, though, the beauty of meatloaf lies in the almost infinite ways in which it can be customized. So long as your ratio of meat to binders is correct, the sky's the limit as to what you can do. I sometimes add chopped pickles or briny olives. Pine nuts or almonds also add texture and flavor. My mother—who, I believed for a long time, looked for ways to hide raisins where you'd least expect them—would probably enjoy some raisins in her loaf. I'm not one to judge.