Sous Vide, Revisited
In a previous post, I had recommended the 4130 NIST-Traceable Temperature Controller to control the temperature in a slow cooker. Unfortunately, that particular controller has a range that tops out at 60 degrees C / 140 degrees F, which is enough for cooking beef for long periods of time, but not enough for say, cooking duck confit, which for which a sous vide temperature of 80 degrees C is recommended. In addition, the 4130 is pretty expensive; almost $150. It’s possible to add a resistor to change the range of the 4130, but the temperature displayed by the controller is no longer correct, and you have manually create a conversion table between true temperature and the temperature as seen by the controller.
I’ve recently come across a cheaper and better possibility, the Ranco ETC-111000-000 Temperature Controller which is only half the price and comes with a much larger working range (-30 to 220 degrees F). The price with the AC cord already wired in is $75; and the version which just has a 120VAC SPDT relay is only $60.
A bit more about food safety. There has always been a lot of concern about bacteria growth and botulism, for good reason — and so therefore the recommendations for cooking temperature have a lot of safety margin in them — to the point now that the USDA recommends that steaks be cooked to at least 145 degrees F, which is well within what had traditionally been called “medium”, and chicken to at least 165 degrees F, which is enough to really destroy taste and texture. Sous vide cooking, especially some of the more low temperature variants, have raised a lot of concerns, to the point where a few years ago New York City (temporarily) banned it, causing a great outcry in the foodie community, since many top restaurants use sous vide techniques.
First of all, any recommendation about internal temperatures and food safety that doesn’t also factor in time is massively oversimplifying the problem. Here is a table taken from “Food Safety Hazards and Controls for the Home Food Preparer”, published by the Hospitality Institute of Technology in 1994:
<td> Time, 5D kill </td> <td> Time, 6.5D kill </td> </tr> <tr> <td> 130 </td> <td> 86.42 minutes </td> <td> 112.34 minutes </td> </tr> <tr> <td> 135 </td> <td> 27.33 minutes </td> <td> 35.53 minutes </td> </tr> <tr> <td> 140 </td> <td> 8.64 minutes </td> <td> 11.23 minutes </td> </tr> <tr> <td> 145 </td> <td> 2.73 minutes </td> <td> 3.55 minutes </td> </tr> <tr> <td> 150 </td> <td> 51.85 seconds </td> <td> 1.12 minutes </td> </tr> <tr> <td> 155 </td> <td> 16.40 seconds </td> <td> 21.32 seconds </td> </tr> <tr> <td> 160 </td> <td> 5.19 seconds </td> <td> 6.74 seconds </td> </tr> <tr> <td> 165 </td> <td> 1.64 seconds </td> <td> 2.13 seconds </td> </tr>