Tuesday, June 30, 2009

Mystery Meat

It seems a general consensus among most senior cooks that meat cookery is the easiest. It is a simple matter of heat transfer, nothing more. An experienced cook will - through years of experience - be able to easily intuit the doneness of a piece of meat.

We've come to the point technologically where we are able to affordably and precisely control our cooking temperatures to an exact degree. Intuition is traded for cognition. Thus the question: what is the optimal temperature at which we cook beef? what is the optimal temperature at which to cook an egg? pork shoulder? a potato? lentils? lambs tongue? chicken thighs?

Stephen Baldwin's comprehensive guide to sous vide cooking contains great recipes, temperatures and times. However, they are contradictory with personal experience and other reearch.

I'm finding myself in my kitchen about to make a braise sous vide and not knowing what temperature to cook it at. Should we go 55C for 48 hours? 60C for 24 hours? 80C for 8 hours? Every source calls for different times and temperatures. Since the method of sous vide cooking is relatively new and not widely used outside professional kitchens, recipes can be difficult to come by. While I can braise a short rib to amazing succulence using a traditional method, I can't honestly tell you what to set the dial to before dropping the bag in the water.

Preliminary Research:

I use short rib as an example because it is very popular tough cut of beef. I've seen recipes that range from 4-36 hours at 55-90C. Short rib is likely optimally cooked to a range of a few degrees. Why, if we can control temperature to the exact degree, is there a 35 degree discrepency?

Beef contains natural enzymes that weaken the connective tissue that makes it tough. These enzymes are most active between 50-55C where they become denatured (mcgee 152). However the protein mysosin coagulates at these temperatures which accounts for some of the firmness of underbraised short rib (mcgee 150). A traditional pot roast or braise will be cooked until the collagen dissolves into component proteins, gelatin which creates a succulent mouthfeel characteristic of braised meats even though the meat itself is somewhat dry. The temperature at which collagen dissolves, 60-70C, also causes muscle fibers to shrink and squeeze out most of the moisture (mcgee 150).

Cooking tough cuts of beef between 50-55C creates a curious product. The meat is medium in doneness and takes on a wonderfully tender texture like tenderloin. The surface acquires an extremely unnerving greenish color. Will people be thrown off by a tender pink short rib? Cooking it over 55C on the other hand will result in the denaturing of the tenderizing enzymes without necessarily dissolving the tough collagen. In theory one could braise short rib indefinitely between 55-60C and never have a tender product. I actually did this by mistake and was very confused why my 18 hour braise was tough as nails.

A possible solution might be to cook the short rib at 50-55C for several hours to allow for tenderization and then raise the temperature to 60-65 for a shorter time to denature the collagen.

This is all very interesting to learn the science behind cooking meat. However, when I'm in the kitchen I just want to know the temperature at which to set the device and could care less about myosin, collagen etc. I don't believe in a magic temperature, I do however intend to answer all these questions I ask above.

1 comment:

Hank said...

I know how you feel! It sucks trying to figure out the right temperatures. On the other hand, the experimenting is fun (usually).

For short ribs I have settled on 36 hours at 55C/131F. I haven't had problems with residual collagen, although 24-48 hours at that temperature still has lots of rubbery connective tissue.