The Science Of Rubs
"Bam! That's what you do with spices!" Emeril Lagasse
Some foods just don't need anything other than a little salt and pepper. A great steak comes to mind. On the other hand, some meats love swimming in sauces. Like pork ribs. Other meats are not very flavorful on their own, and are a blank canvas that is easily painted with herbs, spices, and flavorful liquids. There are several ways to amp up the flavors of foods before cooking.
When chefs speak of seasoning a dish, they are usually not referring to adding herbs and spices. They are usually talking about salt and pepper. Period. And most chefs think that these two basic additives are absolutely positively essential. Salt is an excellent flavor enhancer because it actually opens up your taste buds and this really wakes up the flavor of meat and vegetables. It also helps meat retain water. If your diet requires low salt, go easy on it, but if you can handle a little, don't skip a little "Dalmatian rub", just plain salt and pepper, on almost anything. Click here to read more about salt and the different types of salt.
When the rest of us speak of seasoning, we usually mean salt and pepper and all the other flavorings. Spice blends, commonly called dry rubs, and wet rubs, which are spice blends mixed with water or oil are a great way to amp it up to 11. Pesto is a classic wet rub made with an oil base.
Dry rubs are a mix of spices and dried herbs and they are rubbed into the meat before cooking. They come in a wide range of flavors. There are barbecue rubs, chili powder (yes chili powder is a spice blend), curries, jerk seasoning, sate, Old Bay, and many more. Find some rub recipes you like, make a big batch, and put them in a large spice shaker with a lid. If it clumps or cakes, you can do what waitresses in diners have been doing forever: Dry some rice in the oven or a pan and add it to the jar to absorb the moisture.
You can buy pre-mixed rubs, but they are easy to make yourself, and a lot cheaper since most commercial rubs are loaded with salt. Every good barbecue cook should have a few signature house rubs to brag on. Just steal my recipes. Click here to see a list of them with links to the recipes. Then experiment with variations. But remember, you cannot judge a rub raw. It tastes very very different after cooking. The juices of the meat mix with the herbs and spices, melt them, and they undergo chemical reactions catalyzed by the heat of the fire. A rub may taste too hot when raw, but keep in mind there will be a bite sized piece of food underneath it diluting it. You may hate rosemary, but you'll never notice it in the blend, after mixing with juices, after cooking, and in with a mouthful of pork. As always, I recommend you make my recipes unaltered the first time, and after you cook with it you can then alter it to your tastes.
The four Ss
A good rub is like a good orchestra, it has a range of instruments to play all the notes in harmony. They are:
Sugar. Sweetness is a common addition because it is a flavor enhancer, it helps browning, and with crust formation. Diabetics often ask me if there is a substitute, and the answer is no. The chemical properties of sugar are unique. So let's do the math. Let's say you apply 2 teaspoons of Meathead's Memphis Dust per side of a slab of Baby Back Ribs. It is about 50% sugar. So on a slab of ribs there is about 2 teaspoons of sugar. During cooking, some of it melts and drips off. So if you eat half a slab you are getting less than 1 teaspoon of sugar. The glycemic load is about 3. Compare that with a slice of white bread with a GL of 10.
Savory. There is an herb named savory, and in common language we speak of savory as being a pleasant smell or taste, but in the culinary arts, savory flavors come from amino acids called glutamates, green herbs, some spices, garlic, and other flavorings.
Spices and herbs. Not all of them work on all foods, but the spice rack is full of great flavors. Paprika is often included, not so much for flavor as for color. Click here to read more about spices and herbs.
Spicy. Hot pepper sensations, often called spicy flavors, are often in rubs because they add excitement, but go easy, not everyone likes it as hot as you do. Black pepper is common, so are ground hot peppers such as cayenne or chipotle. Ginger, horseradish, and mustard powder also fit in this category. Click here to read more about chiles.
No salt in rubs!
Salt penetrates, so the amount we apply depends on the weight of the meat. All the rest are huge molecules that rarely go beyond 1/8" deep. Spices and herbs are a surface treatment just like sauces so the amount we apply depends on the per square inches of surface.
Applying the salt separately and in advance is a very important technique called dry brining. Dry brining is simply salting thick cuts the day before cooking and thin cuts an hour or two before. Adding salt in advance is good for the meat because it melts on the wet surface of meat and it penetrates deep. You should click this link and read more about dry brining.
Adding spices in advance does little to benefit the meat below the surface because they cannot penetrate. Read more about why rubs and marinades don't penetrate in my article on marinating.
You need more salt on a pork shoulder than on pork ribs because a shoulder is thicker. You need more salt on rib roast than a ribeye steak, and more on a ribeye steak than on skirt steak. You need more salt on chicken breasts than on thighs or drums. You need more salt on the thick part of a leg of lamb than on the thin part. You don't need more spices on any of these because they don't penetrate. Keeping salt and the other Ss separate lets you apply the right amount of each.
There are other good reasons to keep salt separate:
(1) You do not need any salt at all on cured meats like a ham, bacon, or corned beef, but you might want sugar, savory, spices, and spicy.
(2) Nowadays almost all turkeys and many ribs, pork loins, chickens, and other meats are injected with a salt solution at the processor. This helps meat retain moisture, and adds weight which means profit. This trend is not going away. Many readers tell me they cannot find ribs that have not been pumped. Meat that is labeled "enhanced" or "flavor enhanced" or "self-basting" or "basted" has been injected with a brine at the packing plant. Kosher meat has also been treated with salt at the plant.
(3) Some people like more or less salt than others. By keeping it separate you can tailor saltiness to your taste.
(4) Some people are on salt restricted diets, although when you do the math, the salt used in preparing meat, up to 1/2 teaspoon of kosher salt per pound, is way below your limit.
(5) Some rubs are mixed with oil, and salt will not dissolve in oil. If you apply salt first, the water in the meat will pull it in. Then the oil won't interfere.
(6) Leaving salt out of the mix also gives you room to add a finishing salt just before serving. A sprinkle of large grain salt on a steak as soon as it comes off the grill give it real pop.
You can add the salt at the same time as the spices. No harm, no foul. It will still penetrate, maybe not as deep, but it will travel when it gets wet and warm. But if you can get it on in advance, you give it a head start. Injecting is also a good idea. You should consider injecting thick meats, especially beef brisket and turkey breast (if they are not already injected).
I know almost all commercial rubs have salt in them. Sometimes half the blend is salt. That's because salt is cheap and rubs are expensive. The more salt, the more the profit. Besides, most rub manufacturers haven't figured out the science and if they took the salt out they would be so expensive people wouldn't buy them. All the more reason to make your own rubs starting with my recipes.
So salt, rub, and sauce are three separate applications. You wouldn't add the sauce to the rub would you? We often have to teach newbies not to apply sauce til the end of the cook. Let's learn to add salt in advance. Salt, rub, and sauce are like antifreeze, oil, and gas. They all go into the engine, but don't mix them! Apply them in the right proportion at the right time. Or to carry the metaphor a bit farther, applying the salt, the rub, and the sauce separately is like controlling the gas pedal, break, and clutch. Work them in harmony but separately.
Keeping the salt in one hand and the rub in the other gives you a lot more freedom and control. Remember, you can always add salt, but you can't take it away.
Water or oil under the rub?
You can put a rub right on bare meat, or you can help it stick by moistening the meat with a little water, oil, or a slather of mustard or ketchup. We hope that the spices and herbs will melt a bit, make a nice flavorful slurry that will become a major part of the desirable flavorful lovable bark when it is heated and dries out.
Here's a little experiment I did. I put my two most popular rubs in oil and water. Meathead's Memphis Dust, which is mostly spices, and Simon & Garfunkel Rub, which is mostly herbs. As you can see, they dissolved much better in water. My experience is that they make little or no difference in the final outcome. I also tried them in 40% vodka and they dissolved a little better than water, but alcohol can really mess with the structure of protein so I don't recommend it.
Many cooks like to use a base of bottled mustard under their rub. Bottled mustard is a mix of powdered mustard with water, vinegar, and/or white wine, all mostly water. The amount of mustard powder is so small that by the time the water steams off and drips away, the mustard powder remaining is miniscule. If you want a mustard flavor, you will do much better by simply sprinkling it on the meat. Far more important is what is in the rub than under the rub. So use whatever you want.
Bloom your spices
Toasting many spices amplifies their flavors by releasing their oils and changing chemical sconstructions through the maillard effect. So here's a trick to take your rubs to the next level. Warm a frying pan over medium heat and pour in your spices. Stir or shake them often. Don't let them sit still for more than 10 seconds or they can burn. It only takes about two minutes to bloom them. You'll know when the fragrance jumps out at you.
Either pour them out of the hot pan immediately or else they will continue to cook and burn or, if you wish, make a wet rub by adding some oil, not a lot, just enough to make a paste, and turn the heat as low as possible and cook for another minute so the oil will pull out more of the flavor.
Applying a rub
To prevent contaminating your rub with uncooked meat juices, spoon out the proper amount before you start and seal the bottle for future use. Keep your powder dry.
There is a popular myth that you should not rub a rub, that you should sprinkle it on because rubbing it in cuts the surface and juices will run out.
Humbug. There is a reason they are called cuts of meat. Meat is muscle that has been cut to remove it from the bones, fat, and other muscles. The surface has already been in a knife fight and there are gazillions of muscle fibers that have been sliced open. There are also bazillions of microscopic ridges, valleys, cracks, crevices, pits, pockmarks, and pores in the surface. The surface is far from smooth. Rubbing a rub into the surface can't hurt it one bit. It is not going to lose any more juice than if you just sprinkle it on. And rubbing might just help the meat hold onto the rub better.
To prevent cross-contamination, one hand sprinkles on the rub and the other hand does the rubbing. Don't put the hand that is rubbing into the powder.
Skip the plastic wrap
After salting, the best arrangement is on a wire rack over a pan, no wrap. There is nothing about plastic wrap that forces salt or rub molecules into the meat. It is not some sort of vacuum or pressure system. Plastic wrap just gets stuck to the rub and pulls it off when we remove the plastic. Liquid also accumulates in the plastic and washes away some of the spices. If you are dry brining poultry, you actually want airflow around the meat to help desiccate the skin.
In the restaurant world you are required by law to cover or wrap the meat so juices won't contaminate other foods like veggies. This makes sense, so be very careful if you leave raw meat uncoverd in the fridge. If you wish, a roasting pan with a rack and a dome will work just fine.
If there are odors in the fridge, if there is something really smelly in there, plastic wrap will help keep out the smell, but remember, plastic wrap does not prevent air from entering and exiting, so if there is one of Tony Soprano's dead friends in your fridge, the smell can penetrate most plastic wraps.
Otherwise, just leave the meat nekkid on a rack in a pan on the bottom shelf of the fridge. If you feel safer wrapping, go ahead. It really won't hurt much.