The Pizza Lab: Sausages And the Science of Salt
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Any serious discussion about the state of pizza in the United States must eventually lead to sausage. Though we coastal city folks tend to be purists when it comes to our cheese slices, in most of the country, not ordering at least one sausage pie is not even an option. Indeed, in large swaths of America, a pizzeria is judged not just by the quality of its crust, but by the quality of its preferably-homemade-but-definitely-at-least-custom-blended-by-a-master sweet Italian fennel sausage.
And well it should be. Truly great sausage is hard to come by.
What do I mean by truly great? Well, first off, it's got to have the right texture. Juicy and fatty, with a nice spring to it and a resilience that I would describe as almost rubbery, if that word didn't already have so many bad connotations. Let's call it... mildly bouncy. As it cooks on top of the pie, it should slowly ooze flavorful fat and juices into the sauce and cheese surrounding it, saturating the entire upper crust of the pie with its sweet, porky, savory, fennel aroma. A perfect sausage slice is the quintessence of synergy.
Needless to say, a "sausage pizza" made by adding slices of cooked sausage to a regular cheese slice the way too many corner slice joints do it will never achieve this glorious harmony. You want your sausage applied in raw chunks before the pie goes into the oven. Ideally, the top edges of the sausage will crisp up and begin to sizzle just as the pizza finished cooking, giving you not only flavor enhancement, but a bit of textural contrast in each bite as well.
I'm sure that many Chicagoans will disagree, but for my money, the sausage pie at Zuppardi's in New Haven is about as good as it gets.
I mean, just look at it:
That is, it's as good as you can get outside your own kitchen. What's that? Never made sausage before, you say? Don't worry. By the end of the day, you'll be a pro.
Before we begin, here's a quick pop quiz: What's the most important ingredient in a sausage?
Count slowly to 30 while staring at this picture of Alex Trebek looking very presidential before you answer.
Now, a good portion of you probably cried out, "the meat!" causing co-workers, spouses, and/or pets to wonder exactly what it is you do on that computer all day. That's a good guess, but it's wrong. See, good meat, well, yeah, it's important, but a sausage can be made out of pretty much any type of meat. Pork, duck, turkey, beef, chicken, venison, even fish or scallop. You name it, and if it's got muscles and fat, it can be turned into sausage.
Ah, you've now said to yourself. Fat. That must be it. Better guess, but still not quite right. True, all good sausages have fat in them, and plenty of it. But again, the exact type of fat doesn't matter all that much, so long as it's solid at room temperature and turns juicy and melty when hot. In fact, fat content in sausages can range anywhere from about 20% in a lean Italian fennel or bratwurst, all the way up to nearly 35% for a delicately emulsified boudin blanc or mortadella.
Well then, it's got to be the seasonings. Herbs, spices, aromatics, and whatnot, right? Nope. In fact, the flavorings are probably the least important part of a sausage, because they are almost entirely up to a matter of personal taste. You like garlic with your pork? Go ahead, it won't change the basic structure or science behind making it. Prefer yours with smoked paprika and coriander seeds? That works too. You could flavor your sausage with camel droppings, for all I care. Any changes you make in flavoring are completely superficial.
So what is the most important ingredient in a sausage?
That's right. Plain, simple, humble Sodium Chloride. NaCl. Indeed, the word sausage itself comes from the Latin root for salt. In other languages, that meaning is not quite as obfuscated. Salchicha in Spanish, or salciccia in Italian, for instance. Why does salt make such a big difference?
Let's take a look.
A Sausage Worth Its Salt
My mother and I are constantly at odds when it comes to food. I tend to like things saltier than the average person, while my mom can't abide even a pinch of it. We usually end up compromising somewhere in the middle, but there is one food my mother will never get to enjoy in a low-salt variant: sausage. As anyone who's ever tried to make a sausage without salt will tell you, it simple does not work.
To prove this, I ground up two batches of pork, both cut from the same shoulder. The first was seasoned with a 2% salt mixture (to make sausage, you must use a scale) and allowed to rest for 8 hours. The latter was left completely unseasoned. I ground both of them in a meat grinder, formed them into balls, then poached them in 180°F water until they reached an internal temperature of 160°F before cutting them in half. Check out what happened:
You can plainly see that while the sausage on the left held together with a smooth, resilient texture, the sausage on the right completely crumbled, in much the same way that an overcooked burger will do.
See, despite the fact that ground meat looks like, well, ground meat, it's actually got a fairly complex structure. In their whole form, muscle fibers resemble thick bundles of telephone cables, where each individual wire inside the bundle is a single protein. Chop up these cable bundles, like you do when you grind meat, and you end up with a whole bunch of shorter bundles. Shorter, but still intact: the protein strands are still held tightly within.
Even if you mix them thoroughly, kneading the meat like bread dough, you'll only succeed in some very minor cross-linkage between these short proteins. It's just about enough cross-linkage to ruin the texture of a burger, but not enough to create the bouncy, tightly bound texture of a sausage. You end up with something that would win first prize in a worst-of-both-worlds competition.
Salt changes everything.
Here's what's going on inside those chunks of meat after you salt them:
At first, some of these juices are drawn out of the meat through the process of osmosis. That's the tendency for a solution to travel across a permeable membrane in the direction of lower solute concentration to higher concentration (translation: when there's lot of salt outside of the meat and not much inside, water from within the meat will travel out to try and even out the concentration on the outside and the inside). The salt then dissolves in these juices, creating a briny liquid. Certain meat proteins, namely myosin, will partially dissolve in the presence of this brine.
Essentially, the bundles of telephone wires become looser, their ends fraying out. You can see this happening when you let a chunk of salted meat sit. The exterior gets darker and darker as the proteins dissolve. This makes it far easier for the proteins to then cross-link when you knead the ground meat. Indeed, just by feeling salted ground meat vs. regular ground meat, you can instantly tell the difference: the salted meat is much stickier.
In Good Time
What about timing? Does it matter how long you let your salted meat rest for? To test this, I divided one pork shoulder into eight different test batches. The first batch was left completely unsalted. The remainder were salted for intervals of time ranging from 24 hours all the way down to immediately before grinding. I then cooked all of the ground meat in vacuum-sealed bags in a 60°F water bath and weighed what was left after draining them.
As you can see, there's a pretty clear advantage to letting your meat rest before grinding and forming the sausage. A wait of two hours saves you half of the juices that would have been lost, while four hours saves you a full 75%. Not bad. Beyond eight hours or so, the changes become incremental, shaving off a half percentage point or two before finally maxing out at around a 3.6% moisture loss level after a few days of salting.
With salt testing finished, all that's left is to figure out the best way to grind meat. Luckily, this is a topic I've explored in great depth in a previous Burger Lab post, and the results are not all that different for sausage. Here are the basics.
Keep Everything Cold
Aside from proper salting, this is the single most important step in good sausage making. Both the meat and the grinder must be properly chilled before you begin. See, fat and meat both soften as they get warm, and grinding creates an awful lot of friction, meaning that your meat has a tendency to heat up just by the very nature of grinding. Soft meat and fat = poor chopping. Fat smears out of the meat, and you end up with mush instead of fat and meat evenly distributed, like this:
Left = poorly ground, smeared crud. Cook it, and the fat will pour right out, leaving you with a cottony ball of lean meat. The dry corpse of a sausage.
Good chilling will allow the fat to remain properly distributed throughout the meat in little juicy pockets that baste the sausages as they cook, keeping everyone well-juiced and happy.
Grinder, Food Processor, Or By Hand?
I almost exclusively use the meat grinder attachment for grinding meat. It's fast, efficient, inexpensive if you've already got a stand mixer, and produces the best results short of hand-chopping, which is a real pain in the butt.
I've blabbed more than enough about how to properly use a grinder, so I won't repeat it here (just click through that link). Long story short: keep everything cold, store the grinder in the freezer, and grind fast.
If you don't have a meat grinder, a food processor will get the job done as well. Rule numero uno still applies: keep it all cold. In a food processor, you'll want to get your meat even colder. Throwing it in the freezer in a single layer on a tray for fifteen minutes or so helps a lot. So does grinding in small batches.
The Need to Knead
Now, salted ground meat will taste just fine on its own, but to really develop some true snappy sausage texture, you need to knead it. And when I say knead, I mean that literally. It is exactly like kneading dough for a loaf of bread, and the end goal is the same: the development of protein within the mass.
Just as kneading causes proteins in the flour to cross-link with each other forming a strong network that gives your bread structure, so kneading will cause meat proteins to cross-link, creating a strong network that gives your sausage resilience.
You can do your kneading by hand inside a bowl, but if you've already got the stand mixer out for grinding, the easiest thing to do is to grind the meat directly into the bowl of the stand mixer, then immediately beat it with the paddle attachment right after you finish grinding. You'll see it transform from a loose pile of meat to a sticky, cohesive blob within a minute or so.
Remember when I said that flavoring doesn't really matter? Well that's absolutely true. It's completely a matter of personal taste. A plain sausage made with just pork and salt will still be mighty tasty if prepared properly (which, of course, it will be now that you've read this post), just as a fine specimen of a man or woman will look great even in their birthday suit.
But sometimes its nice to add a little something to spice things up a bit. Think of flavorings as sexy underwear for your sausages.
The basic seasonings for what we call "Italian Sausage" are fennel seed, garlic, and black pepper, though I find that a touch of sugar helps bring out the sweetness of the pork. Many recipes call for basil. I prefer the slightly more robust flavor of dried marjoram (not mandatory by any means), and since I like my food hot, I also throw in a bit of red pepper flakes and cayenne into the mix. You can leave this out or add even more if you'd like.
Some recipes have you grind the spices before adding them to the sausage. I prefer to toast mine whole and add them as-is to the meat as it sits in its salt bath overnight. They get crushed as they pass through the grinder along with the meat, giving you plenty of even flavoring without the need to whip out the spice grinder.
The sausage you end up with is as fine a specimen as you could hope for. Well seasoned, great texture, and plenty juicy with a nicely balanced spice level. The only step remaining: how to cook them.
Of course, you can always stuff them into casings and cook them just like you would any sausage,* but we're talking pizza today, and when it comes to pies, there's only one way to properly cook sausage: apply raw, and apply heavily.
After visiting countless pizzerias and watching the piemen in action, I'm amazed at the variation you can find in sausage application technique.
Frank Pepe's in New Haven probably has the most impressive application process. A duo of cooks apply it rapid fire, one hand holding the chunk of sausage, the other ripping off bits that fly out staccato shots like machine gun fire. They completely cover the surface of a pie in a matter of seconds.
Other pizzerias like to take their time. The Colony Grill in Stamford, Connecticut, is very meticulous about their sausage formation, making sure that each slice of the pie gets the exact same number of evenly spaced, evenly shaped, perfectly spherical chunks.
*That would be a gentle poach followed by a hard sear or grill to cook them evenly and prevent overcooking, but you knew that, right?
But the best method I've seen to date was at DeLorenzo's Pizza in Trenton New Jersey, where Rick DeLorenzo Jr. pulls of bits of sausage and rolls them in a bit of flour before dropping them on top of the pie. Not only does this method prevent the sausage from sticking to your fingers when you drop it, it also helps it to retain more fat and moisture, as well as gives it superior surface browning.
See how gloriously the fat, meat, cheese, and tomato intermingle?
Sausages are a never-ending can of worms. I mean, we haven't even begun to talk about complexities such as cooking temperature, cuts of meat, fat content, aging, drying, emulsified sausages, stuffing, smoking, fermenting, or any of the other dozens of ways in which sausages are treated to convert them from awesome-like-a-hot-dog to awesome-like-a-hundred-billion-hot-dogs.
But that's another story for another time.
About the author: J. Kenji Lopez-Alt is the Managing Editor 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.