It's grilling season and, although I've vented my spleen on gas grills already, as my friend Bob pointed out, "roasted meat is roasted meat, and it tastes good." No doubt.
To make that grilled dish even better, many believe that marinading is the logical pre-step. After all, bottles of the stuff line store shelves and you can even find devices to inject marinade literally into the roast or chicken breast. On top of all that, recipe after recipe for grilled food calls for marinading with the word "tender" sprinkled liberally throughout. Not so, say the experts...it's time for some tough love about tender.
The Truth About Tenderizing
Marinades—at least the acidic kinds—don't tenderize protein foods like meat, they actually cook it. You know how fish turns white in lime juice (think Ceviche)? Acid denatures the protein, which basically means it busts up the natural, tidy structure leaving behind a chaotic mesh of protein strands.
Depending on how much acid is involved, this bramble bush of protein can become tough. Cooking with heat also denatures protein, and like the acid in the marinade, it's a matter of degrees. Too much acid, like too much heat, renders meat tough. So go easy on the acid in the marinade...there's really no tenderizing happening there. What's more, unless you're injecting your meat, all the action is really taking place only on the surface anyhow.
But what of pineapple and papaya juice? Doesn't all that exotic tropical fruit work magic on meat to make it tender? While you could say meat treated with the natural enzymes in pineapple and papaya definitely make meat softer, tender would be a stretch. Subjecting meat to an enzyme bath is more like leaving your cake out in the rain...definitely softer, but not very appetizing. Yuck.
Another popular tenderizer—for chicken, at least—is yogurt, milk, and buttermilk. It's theorized that if any tenderizing is taking place at all, it may be from calcium in the dairy triggering enzymes already present in the meat. Questions remain about whether this is really what's happening. The only other obvious component that could be doing anything would be lactic acid in yogurt or buttermilk, and as we've already seen, acid doesn't really work.
Isn't the proof of the pudding in the tandoor? Tandoori chicken is marinated in yogurt, and there's no doubt that texture on the skewer didn't arise from the tandoor alone. The reason, however, may not be the yogurt. These marinades usually call for lots of ginger, a root that contains enzymes (a la pineapple and papaya) that could be doing the same softening.
Are Marinades Good for Anything?
Chris Schlesinger chef of the East Coast Grill, ex-chef of the Blue Room (both Boston favs) and author of "The Thrill of the Grill" advocates dry rubs over marinades. The reason is simple: dry rubs impart more intense, concentrated flavor without any of the negative side effects associated with acidic marinades. You'll use a bunch more oregano in a dry rub than you would ever put into a marinade.
However, if you keep the acid level low enough to avoid toughening your meat, marinades can certainly flavor grillables. And a small amount of acid sets the stage for a more productive, voluptuous browning to occur in the heat of the grill, oven, or pan.