re: Beef Shank w/ pic

LINK

quote:

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Prolonged cooking (e.g., braising) has been used to make tough cuts of meat more palatable since ancient times. Indeed, prolonged cooking can more than double the tenderness of the meat by dissolving all the collagen into gelatin and reducing inter-fiber adhesion to essentially nothing (Davey et al., 1976). At 176°F (80°C), Davey et al. (1976) found that these effects occur within about 12–24 hours with tenderness increasing only slightly when cooked for 50 to 100 hours. At lower temperatures (120°F/50°C to 150°F/ 65°C), Bouton and Harris (1981) found that tough cuts of beef (from animals 0–4 years old) were the most tender when cooked to between 131°F and 140°F (55°C and 60°C). Cooking the beef for 24 hours at these temperatures significantly increased its tenderness (with shear forces decreasing 26%–72% compared to 1 hour of cooking). This tenderizing is caused by weakening of connective tissue and proteolytic enzymes decreasing myofibrillar tensile strength. Indeed, collagen begins to dissolve into gelatin above 122°F to 131°F (50°C to 55°C) (Neklyudov, 2003; This, 2006). Moreover, the sarcoplasmic protein enzyme collagenase remains active below 140°F (60°C) and can significantly tenderize the meat if held for more than 6 hours (Tornberg, 2005). This is why beef chuck roast cooked in a 131°F–140°F (55°C–60°C) water bath for 24–48 hours has the texture of filet mignon.

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Different types of meat will require facilitating cooking times. For instance, I only let salmon swim for 45 minutes max. There's no way I would hold a chicken breast for 72 hours at that temp merely because it will affect the texture of the meat. I once did a chuck steak too long and I could mush my thumb into the meat. Tossed that baby right into the trash.

There's so much to learn about sous vide with relatively little info out there since it's a newer concept and I'm certainly no expert. I'm just sort of borrowing concepts from the various places that I can find info.

What's interesting is some of the sources absolutely contradict each other...whether to salt something before it's bagged, also when to sear it, before or after, cooking times, temps, etc.

Thomas Keller is one of the pioneers and someone you should look into if you want to start experimenting in sous vide, but the one knock with him is that his cookbook is so advanced even the above average home cooks won't have access to various exotic ingredients. Douglas Baldwin has done extensive research and is also a pioneer and seems to be more home cook compatible. I've provided a link earlier to an insightful website, but he also has a book Sous Vide For The Home Cook which is worth picking up.