It doesn’t matter if you’re roasting at high heat, grilling over an open flame or going at it low and slow, every piece of meat (no matter the cut) experiences the same internal transformations – the only thing that varies is the speed with which those transformations occur, and that all depends on how you cook it.
Believe it or not, there are biochemical changes going on inside that steak, pork roast and brisket to get them to their “perfect” doneness. It’s a process called denaturation and it involves the breaking down of protein strands by the application of extreme conditions (i.e time and temperature) that ultimately render meat moist and tender.
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Denaturation begins at roughly 105°F and continues upwards to temperatures in excess of 200°F. Changes in proteins can be seen in the form of changing colors (i.e. red to brown) and can be tracked at each stage by the use of a meat thermometer. Ideal cooking temperatures found on the chef-recommended temperature chart are indications that sufficient denaturation has occurred to render the meat to the color and texture of your choice.
However, just knowing what color and texture it is isn’t good enough for us. We want to know (and we assume you do, too) what’s happening to your meat as it passes through the various temperature stages.
As meat approaches 105°F, the calpains (calcium proteins) begin to denature and lose activity; this happens until about 122°F. Since enzyme activity increases up to those temperatures, slow cooking can provide a significant aging effect during the cooking process. At *125°F meat is rare. Ideally, you’ll want to sear the meat quickly to kill any surface bacteria.
Above 125°F, meat begins to develop a white opacity as heat sensitive myosin (motor proteins) denature. Coagulation produces large enough clumps to scatter light and red meat becomes pink. This is where the meat moves from rare to medium rare (*130°F).
Further cooking (towards *140°F) begins to breakdown the red myoglobin (iron/oxygen binding protein) and turns it into a tan colored hemichrome. It’s at this point that meat turns from pink, to brown and then to grey.
During this time, meat releases a lot of juices and begins to shrink noticeably. In a very rapid succession it can move from medium rare, to medium, to medium well. And, if you’re not careful, you can very quickly overcook your meat.
At *160°F, connective tissue begins to liquify. Proteins repel the water and constrict causing them to get closer together and grow stronger. This is what gives well-done meat it’s tough and dry texture. At the risk of ruining your main course, you would never want to take your higher quality cuts of meat to this temperature.
However, if you’re cooking low and slow with traditional BBQ cuts, it’s taken you hours to get to this point and things are just getting warmed up. As you accelerate past 180°F and up to 200°F, collagen begins to melt and turn into a gelatin. This gelatin is able to absorb up to ten times it’s weight in water. The moisture that is repelled by the protein is absorbed into the gelatin and the meat stays moist.
In some cases it can take up to 12 hours for a pitmaster to complete a cook on a pork shoulder or beef brisket. The prolonged exposure to the low heat of a barbecue pit will sufficiently render the fat in a tough piece of meat and leave it moist and flavorful.
(*Never forget to take into account that the internal temperature of the meat will rise during the rest. If you remove a piece of meat from the grill when it’s hit your preferred temperature it will likely be overcooked as the residual heat takes it above your desired temperature. Removing your meat from the heat when it’s a few degrees away from your ideal temperature will ensure that it’s perfect when it’s completed the rest.)
The only question that’s left is, “How do you like it cooked?”