Zest or Juice? An Experiment with Fajita Marinade - and The Surprising Results!

Sandy and I went to Santa Fe and took some classes at the Santa Fe School of Cooking - it was an incredible culinary experience - I highly, highly recommend it for a fabulous getaway for any foodie interested in southwest foods.  I learned so much in just a few days - but I heard one thing that shocked and puzzled me. I attended a class called "Fajitas!," with Chef Susan Anzalone. She said this -

"Never add acid to marinades for meats. NEVER. It will toughen the meat, just like it does in ceviche. Use zest if you want citrus flavor."

Huh. (==scratches head==) This stunned me, because for years I have used lime juice in fajita marinades - with chicken and flank steak. So, I did some research seeing what some of my favorite chefs recommend for fajita marinades.

Alton Brown, a culinary hero of mine, calls flank steak "the most marinatable hunk of beef there is" in his book I'm Just Here for the Food. But, he does NOT use citrus in his marinade. On Good Eats, he does use lime juice, but says it does NOT tenderize the meat but only adds flavor. ((( Hhmmmm . . . OK, A.B., one question:  if you're not using juice for tenderizing meat but only flavor, why not use ZEST - it's 1,000 times more flavorful than juice?! )))

Some of my favorite magazines - Bon Appetit, Gourmet and Cooking Light - all use lime juice in their marinades, all recommend varying times for marinating.

And the amazing source America's Test Kitchen (Cook's Illustrated February 2007) uses lime juice, but sprinkles it on right before cooking. So, obviously ATK does not recommend citrus as a marinade.

I went to some of my favorite food blogs - Simply Recipes uses lime juice as a marinade. Kalyn's Kitchen uses just a little lime juice during crock-pot cooking. Serious Eats uses lime and orange juices but a very short marinade time.

Now that grilling season is here, I plan on doing more than my share of feasting on fajitas - but I was confused: how to marinate?

I decided that the only solution in the quest for a perfect fajita marinade was  a true "Donna's Test Kitchen" test: JUICE vs. ZEST. The two marinades I used were identical except one used zest and one used juice.

I marinated two hunks of flank steak  for one hour on the countertop.

I then sprinkled a little lime juice on both hunks of meat and then cooked the two hunks side by side on the grill with the veggies - same temperature, same length of time.

I took off the meat, let it rest about 10 minutes and sliced it.

The clear, not-even-close winner was the ZEST marinated meat. Both hunks were equally tender - because of thin slicing. But, the ZEST marinated meat was by far the most flavorful.

There you have it, southwest food fans! Use ZEST in your next fajita marinade!

 

Steak Fajita Marinade with Lime Zest

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Ingredients

• 2 chipotle peppers in adobo sauce, seeded to reduce heat
• Zest from 1 lime (about 2 teaspoons full)
• Zest of ½ orange
• ½ cup water
• ¼ onion, chopped
• 2 cloves garlic, diced
• 1 teaspoon cumin
• ¼ cup olive oil
• Kosher salt, divided
• 1 ½ to 2 pounds flank steak, trimmed
• Black Pepper (fresh, coarsely ground pepper, if possible)
• 2 red bell peppers
• 1 white onion
• 12 fajita size flour tortillas
• Guacamole
• Sour cream
• Cheddar cheese or Monterey Jack cheese, grated
• Pico de Gallo or salsa
• Green onions, thinly sliced

Instructions

1. Place the chipotles, lime and orange zest, water, onion, garlic, cumin, 1 teaspoon Kosher Salt and olive oil into a blender. Blend until smooth. Pour marinade into a zip bag.
2. Add flank steak to the bag and coat evenly with the marinade. Let stand on the counter for only 1 to 1 ½ hours then, grill or refrigerate. Do not let the meat sit out for longer than 1 ½ hours for food safety reasons. You may also refrigerate for six ours or overnight. Turn the bag occasionally ( I tried both methods with the same result).
3. Remove steak from the bag and remove excess marinade. Season with salt and pepper.
4. Grill steak over medium high heat until medium rare, about 4 minutes per side for medium rare (there should be pink in the middle). Let steak rest before slicing. Slice thinly against the grain or diagonally.
5. Cut the red peppers and onion in half. Remove the seeds and stems. Toss them in a little olive oil and lime juice. Season with salt and pepper and grill them until the skins are slightly charred and they are barely limp. The peppers and onion should still have texture and not be mushy, slice thinly.
6. Heat the tortillas over the flame or in a skillet for 30 seconds to one minute on each side. Cover or wrap in a clean kitchen towel to keep warm.
7. Serve the steak fajitas on warm flour tortillas and garnish with guacamole, sour cream, pico de gallo or salsa, grated cheese and thinly sliced green onions.

NOTE: I MARINATED CHICKEN BREASTS WITH THE SAME ZEST MARINADE, WITH GREAT RESULTS - JUST AS DELICIOUS AND TENDER AS THE FLANK STEAK!