Marinating meats for the grill seems to bring out the inner herbalist in even the most hard-boiled of home cooks. A little olive oil, some lemon juice, a handful of herbs, some exotic spices — whatever smells right. It’s almost like we’re designing a scented bath oil rather than a seasoning for meat.
The truth is, though, that marinades rarely do much good.
Most really don’t have much of an effect. In fact, in some cases — those that call for a long soak — they actually can do more damage than good.
Though composing complicated marinades may be satisfying on a certain intuitive level, with few exceptions, the mixture won’t do much more than coat the surface of the meat. It won’t tenderize it, and it will only impart the more forceful flavors.
No matter how long you soak it, most marinades won’t penetrate more than the outside eighth of an inch. That’s because meat is made up mostly of water (about 75 percent by weight) and water and oily marinades don’t mix. This is true whether you’re marinating for a half-day or for a week.
In most cases, that isn’t actually a bad thing. Most meats we marinate are thin cuts — chicken pieces or beef or pork steaks. With these thinner cuts you’re almost always guaranteed to get a good bit of seasoned surface meat when you take a bite.
In some cases, marinating can actually damage the meat. If you have very much acidity in the marinade — vinegar or lemon juice, for example — too long a bath can make the meat mealy.
This is based on the same science that leads some to believe that marinating “tenderizes.” Acid does denature protein — it unwinds the tightly balled strands — and that does make meat softer.
But remember that marinades rarely penetrate beyond the surface. So what is actually happening is that the outside of the meat is becoming overly tender — mealy — while the inside remains mostly untouched.
To make a tough cut of meat more tender, it’s better to simply slice it thin, either before or after grilling.
If you do want to get more complex with marinades, it’s going to take big flavors to stand up to the taste of seared meat — use garlic, shallots and other members of the onion family and dried peppers and other spices.
Acidity should be considered more a flavoring than a tenderizer — and it’s an important one. Because most of the meats we grill are fairly fatty (that’s what makes them good for the grill), adding vinegar or citrus juice is a good balance.