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Thursday, May 26, 2011

Connecting the Dots - Insight into Sous Vide Hamburgers

I'm working on a recipe for Hamburgers / Cheeseburgers.  But I wanted to share some interesting insight while I'm testing a recipe.

I already had "one dot" on slow, low temperature cooking - the tenderization of tough foods (think slow cooked BBQ here or stews) through low temperatures for an extended length of time.

I also was aware of "another dot" that allows one to cook to lower temperatures but for longer periods of time in order to pasteurize foods.

What I had failed to do was to connect the "two dots".

In recent years, the USDA has recommended higher cooking temperatures for things like ground beef (hamburgers), eggs, etc, to elevated temperatures of 160 dF or so.  In other words, past well done - think charred little tooth-breakers.  They wanted us to do this in order to pasteurize the meat so it did not represent a health hazard.

Which means we need to talk about pasteurization a little bit - not too much, but a little bit.

To pasteurize is not to sterilize - sterilization means to kill all of the 'bugs', whereas pasteurization means to reduce the amount of them, something like 1 million to 1.  So  to pasteurize is to reduce 'the bugs' to the point where their numbers are able to be handled by our bodies.  So in particular where something is cooked, like ground beef, it is important to pasteurize the food before consuming.

However, in the case of hamburger, cooking at normal temperatures, pasteurization is done by heating the ground beef at a temperature high enough to kill the 'bugs' in the short amount of time the hamburger is cooked.

However, there is more to pasteurization.  The way the 'bugs' are killed is temperature and time.  A very high temperature, for a very short time, will pasteurize the food.  A medium temperature for a medium length of time will also pasteurize the food.  And, a low temperature for a long length of time will also pasteurize the food.

From making sure I was producing safe BBQ, I knew all of this from the research I had done.

The Sous Vide method (the translation means, literally, to cook in a vacuum), at its simplest form, is place the food within pouches, then immerse the pouches into a water-bath with a precisely controlled temperature, then cooked at a low temperature for a time sufficient to pasteurize the food.  Cooking it for a long period of time does not over cook the food, it just brings the food up to that temperature.  Cooking it for an extended length of time, typically way past the point of pasteurization, makes the food very tender.

I have been focused on tenderization of the food as the main benefit of cooking in the Sous Vide style, which requires fairly long times.

The two dots that I failed to connect were the cooking long enough to pasteurize, but no longer, as depending on the food itself, I may not need to tenderize.

So this is where the hamburgers come in (as well as any other food like soft-cooked eggs, etc): I can cook them at rare, medium rare, medium - all that would have been below the USDA's recommendation - but still end up with safe, pasteurized food.

So think about this - safe pasteurized foods attainable at lower temperatures but cooked for longer lengths of time:

  • hamburgers at medium rare.
  • runny eggs.
  • chicken breasts that have juice.
  • pork that has juice (BTW - the new USDA recommended temperatures for pork is 160 dF).
  • home made mayonnaise, which uses raw egg - the eggs can be pasteurized now.
  • turkey breasts that are juicy.
We are cooking our first batch of hamburgers right now using our Sous Vide Supreme, and are using a target temperature of 137 dF - about medium rare.  I'll finish them in an iron skillet to toast them.  A better choice may be to finish on the grill, or if you are lucky enough to have one, a Big Green Egg smoker.

I can't wait!

UPDATE: The hamburgers were moist and very flavorful!  I expect this will be the way we cook hamburger going forward.

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