Last year, I did a taste and tenderness test, comparing tenderloins from grass fed cows with those from grain fed cows (you can read about it at http://dondayinsma.com/2016/12/18/grass-fed-versus-grain-fed-beef-filet-cook-off/). Tenderloins, though, don’t require marbling with fat to be tender and tasty. What about a prime rib? What about the king of cuts? Could a grass fed prime rib roast be as tender as a grain fed? Impossible I thought. But might it be tender enough to still make the grade for a Sunday dinner, especially considering the cut’s low price in Mexico. I was about to find out.

The last time I was in Toronto, my local butcher was selling grass-fed prime rib for $55 Canadian or about $800 MX a kilo. That’s quite the difference from the $168 MX that I paid at my local butcher, La Nueva Aurora, here in San Miguel de Allende. The chuleta or chuletón, as prime rib is usually called in Mexico, is rarely consumed by Mexicans, as a roast or cut into steaks, so it’s priced very low, the same price per kilo as lean ground beef.

Originally, I thought of buying a five or six bone roast and inviting friends but I was afraid this experiment might be a way to lose friends. So I asked Luis the butcher to cut me two ribs from the small end, what is called first cut and comes from closer to the loin. Unfortunately, as it seems with all Mexican butchers, La Nueva Aurora had already cut off the cap, perhaps my favorite part of a rib roast, as well as the fat that separates the cap from the rest of the cut. To make up for this, I asked Luis for a piece of suet that I could place on top during cooking so that the fat would drizzle down and help brown the meat. The fat might also help tenderize the roast but I wasn’t sure.

The two ribs weighed in at almost exactly two kilos and cost $332 MX. There would be enough for a roast beef dinner for two with lots left over for sandwiches the next day.

When I got home, Don Day’s Wife started to work her magic. She liberally coated the roast with a commercial rub called Amos to season it, wrapped it in cheesecloth and placed it in the coldest part of our fridge to age it for a few days. If you’re interested, Supermercado Bonanza here in San Miguel sells a rub called Montreal Steak Spice that is very similar to Amos.

Three or four weeks in the fridge might have been better but the color of the meat suggested the beef already had some aging and, frankly, I was antsy. I couldn’t wait to try it.

Our previous experiences with dry aging of grain fed beef at home suggested that, not only did dehydration enhance the meat’s flavor but also the tenderness as the enzymes in the beef broke down the muscle tissue.

You may be wondering why we didn’t marinate the meat to help break up the connective tissue. Trial and error with liquid marinades had taught us that they only penetrate about a quarter inch into the meat, which is fine for a half inch thick skirt steak but not for a four inch thick prime rib roast. The same can be said for mechanical devices including the celebrated Jaccard super meat tenderizer.

After five days, we removed the roast from the refrigerator and left it for an hour on the counter to reach room temperature. Usually after aging, it’s necessary to trim off the dried and, sometimes, slightly mouldy pieces on the exterior but, with such a short aging period, it wasn’t necessary.

Next Don Day’s Wife made a slice just above the bones and filled it with three large cloves of garlic cut into slivers, a technique that she often uses with grain fed roasts to enhance the spicing.

When she has cooked grass fed tenderloins, Don Day’s Wife traditionally wraps them with bacon. When I was a kid, my dad would rub the standing rib roast (what prime rib was called then) with a generous amount of lard. To keep the beefy flavor, we had switched from pork fat to the suet which we tied on top of our roast with string (I got to hold my finger on the knots).

The oven was preheated to 200°F, the lowest setting of 1 on our gas oven, and in went our grass fed prime rib. We tucked into the den for the rest of a double bill of Chinatown and L.A. Confidential but, no matter how good those films are, the next three and a half hours seemed to take forever.

Finally in went the instant read Thermapen probe (every cook should have one) and out came a beautiful looking piece of meat. 135°F had been reached. The roast would now be medium rare.

A little sneak preview chunk was stolen off the side of the bone and handed to me by Don Day’s Wife. It was very tasty, very moist and not at all chewy. But this was from right off the bone, the tenderest part of the cut, what would the meat be like in the middle. I still had some time (and quite a few scenes with Kim Basinger) before I’d find out.

Many cooks would now tent the roast for an hour. Don Day’s Wife thinks that putting an aluminum hat on the meat does help keep it warm but does very little in contributing to the juices redistributing through the meat while it rests. And keeping the roast warm was unimportant, for the oven had been turned up to its highest level of 450°F (Don Day’s Wife would prefer an oven that goes to 550°F). After a half hour of resting, the roast went back in for another ten minutes to sear and crisp the outside.

Don Day’s Wife began plating the sides. Oven roasted spring onions, baby carrots and celery root, creamed spinach and, of course, potatoes and gravy. Out came the roast and our heaviest Henkel and, to give the beef its best chance at chewability, the slicing was done very thin.

A good California Cab was opened and poured and we sat at the table and took our first bites. I looked at Don Day’s Wife as I began to chew. She looked back at me as she began to chew. We continued to chew and continued to chew and chew and chew and chew. Did you ever see a couple of cows in a field endlessly grinding their way through their cud? You’ve got the picture of us.

“I’m glad I brought that meat grinder down from Toronto”, said Don Day’s Wife. “I think I see some shepherd’s pie…or cottage pie to be more accurate…in our future.”

Don Day’s Wife was correct. As good as the beef looked, it was inedible, totally inedible. It was an utter, dismal failure. A total waste of money.

Our experiment was over. The conclusion was disappointing but, I guess, expected. In my opinion, there is no way to prepare and cook a tender prime rib from locally raised, grass fed beef. End of story.

If you have had any success at all cooking a prime rib from Mexican grass fed beef, I would love to hear about it.