Sous-vide – What does circulation accomplish

Has anyone had success at large scale sous-vide at home?

My scale was not quite as big as yours, but I cooked my Thanksgiving turkey for the extended family this year sous vide. Not only was the outcome a huge hit among the guests, but it was a huge relief for (your truly) the chef.

I want to go to party scale, say 30 to 40 servings, what are my chances of success?

In my experience, scaling up is one of the biggest advantages of cooking sous vide. Cooking 30-40 servings on a home stove would be a daunting prospect, to say the least. With sous vide, 15–20 servings is only marginally more work than 4–6. Again, I've not done 30–40, but it should scale accordingly.

Should I just get three or four chilly bins or just one large bin?

If your food will fit in one cooler, it will work, but I think you'll find it much easier to use more. The more water you have, the slower it will lose heat, and thus, the less you will have to pay attention to it. I also typically cook chicken and beef at separate temperatures, so I would probably have two coolers for chicken and two for beef.

It depends on what is to be pasteurized. If one aims for pasteurizing the surface only, then the shape is more or less unimportant. If however one wants to pasteurize the core, then the shape will affect the times.

To be on the safe size, measure the thickness where the meat is thickest.

Myhrwold writes in http://forums.egullet.org/index.php?/topic/116617-sous-vide-recipes-techniques-equipment-2004-2010/page_st_120_p_982720#entry982720 about cooking times (not pasteurization times):

This is true for any kind of cooking actually. Most of what we are taught about cooking is actually wrong. For example, anytime somebody tells you it is “10 minutes per pound” they are saying something that cannot possibly be accurate, because this would imply that cooking time is proportional to the weight. If you take something like a whole bird and scale it up you will find that cooking time is actually proportional to something like (weight)^(2/3) – weight to the 2/3 power. This is because increasing the weight scales up the thickness by the cube root. Since most people are not accustomed to taking things to fractional powers, people substitute a linear relationship. That might work out OK in practice over a small range, but it can’t be accurate over a large range. For example, if you double the weight, the linear relationship would tell you that you double the cooking time. The 2/3 power would tell you to increase it by 59% - that is a pretty big difference.

As a general rule of thumb heat diffusion times go as the square of the thickness increase. So, doubling the thickness results in FOUR TIMES the cooking time. That is a rough general rule of thumb, which is not perfect but it illustrates the nonlinearity of the system. I don’t know why this isn’t taught to chefs more often because it is a fairly easy thing to grasp and use.

A side note:

If you have an iPad or iPhone then I can recommend SousVideDash. One must enter meat type, shape and size, initial and final temparature. Then graphs are drawn that shows pasteurization times for both surface and core (or more precisely graphs of the reduction of salmonella and listeria).

See the website:

http://www.sousvidedash.com/