The Role of Guinness

• Marinades consist of five components: Oil, acid, aromatics, and salt and sugar to taste. Within those components, you find the five taste sensations: bitter, salty, sweet, umami and sour. In a Guinness-based marinade, Guinness take the place of the oil for aromatization -- it releases the esters and flavor compounds of the herbs and spices as well as oil does. However, a touch of oil helps the marinade adhere to the meat and disperse the aromatic compounds, but you only need to add a little instead of the usual 1 cup or so per 2 pounds of meat. Pour 1/2 bottle of Guinness and 1/2 tablespoon of vegetable oil in a mixing bowl for every pound of meat you want to marinate. In addition to bringing the best out of the aromatics, Guinness imparts its own brand of bitterness, a type you won't find in anything less than a stout of its stature. However, you must temper Guinness' richness with a contrasting taste sensation, and that's where aromatics come into play.

Aromatics for Balance

• Aromatics are the counterpoint to Guinness in a marinade -- the yin to the Guinness yang, so to speak. To balance the boldness of the beer, you want to go with floral herbs and spices to smooth the bitter flavor edges. Aromatics that hit all notes in a Guinness marinade include sage, thyme, rosemary and tarragon. You don't need to use all these herbs, one or two will do -- but it's your marinade, so add them to taste. A word of caution: Fresh herbs go a long way, limit their use to 1 to 2 sprigs for every pound of meat. To prep the herbs, place them in a mixing bowl and bruise them by pressing them with the bottom of a spoon.

Pungents for Piquancy

• Rich ingredients need a contrasting element to put their richness in context, lest it overpower the dish. With Guinness, pungent ingredients work best -- a hint of heat from half a chili pepper, a sliced shallot or two and a smashed knob of garlic frame the caramel-like essence of the beer, heighten its high notes and minimize its low, muggy flavors. Thinly slice a shallot and crush a garlic clove or two to add moderate pungency to the marinade. For a bit more bite, slice a Thai chili pepper in half and add it to the mixing bowl. For a touch of Asian flair, crush a 1/2-inch piece of ginger with the broad side of a chef's knife and stir it in.

Acid for Sharpness

• A touch of acid and umami complete the marinade's flavor profile. For the acid, use an assertive mustard -- about 1 teaspoon of Dijon or whole grain for every cup of Guinness. For umami, add a dash or two of soy sauce, just enough for the glutamates to work their magic.

Marrying the Marinade

• Mixing the marinade and letting the flavors coalesce, or marry, is where it all comes together. Whisk the marinade ingredients, and season it to taste with kosher salt and sugar. Add a pinch of sugar and salt at a time -- you can always add more, but you can never take away, so incorporate judiciously. Next, let the marinade sit at room temperature for about 30 minutes. This waiting period mobilizes the essential oils and esters that contribute flavor to the marinade. Discard the Guinness marinade after use.

The Easy Part

• Place the meat in a glass dish; mix the marinade once more and pour it over the meat. Turn the meat over once or twice to fully cover it, and then wrap the dish with plastic wrap. Place the dish in the refrigerator and marinate the meat between 4 and 24 hours. Turn the meat over every 12 hours while marinating.