|Turkey and stuffing croquettes with a 62-degree egg|
Arne and I were pretty excited for the second week of our food science class, on temperature and heat. For our lab, we were going to play with sous vide cooking, a major darling of today’s chef’s, that I addressed briefly before when I made sous vide shrimp in the kitchen sink. (They were wonderful!)
The science of this week’s lectures focused on measurements of heat and energy – both in terms of the heat that is transferred into food through cooking and the energy in calories that food has to offer the eater. In between the more conventional lectures, there were several demonstrations from the mad-scientist laboratory of Dave Arnold (of the French Culinary Institute and NYC’s avant-garde bar Booker & Dax).
For the homework, we calculated the energy content of some brownies based on the 4-4-9 rule (carbs and protein have 4 calories per gram; fat has 9), and learned the specific heat capacity of water, oil, and eggs. And then we moved on to the labs. There were three this week, of which we were only required to do one: We skipped the one about measuring the thermal change of ice and hot tea, and moved straight to making ricotta cheese and sous vide eggs.
I’ve made ricotta cheese before, and the recipe for this lab was pretty much like the one I posted here. The big difference was the lab’s specificity about how hot to get the milk mixture (and my previous recipe added cream, which I went ahead and snuck into this one as well). The cheese was incredible and easy, and I strongly suggest that if you’ve never made ricotta at home, you give it a try.
It was a little tricky to fill out the lab report for the cheese lab, because we haven’t really covered the scientific principles behind curdling and such yet. We muddled through as best we could, and a couple days later we moved on to the sous vide eggs.
The most interesting lecture section of the week was Dave Arnold demonstrating the great difference between eggs cooked sous vide with very small temperature differences. While an egg cooked at 62 degrees Celsius has a nearly liquid yolk, one cooked at 64 degrees has a fully set yolk, and one cooked at 67 has a yolk that can be molded like putty. We made all three.
The lab called for a remarkably labor-intensive method of cooking these eggs: by adding boiling water to each pot to maintain the temperature as it started to fall. We calculated the range in Fahrenheit at which to keep each pot (because our beloved Thermapen instant-read thermometer is in Fahrenheit), and got to work.
And work it was. We had to maintain the heat in these pots for 40 minutes, and it fell much faster than I had anticipated. By the end we were cranky and very, very ready to be done. But we had some pretty awesome eggs.
The photo above is a 62-degree egg, while the egg below was cooked at 64 degrees. You can really see the difference! We ate some of our experiment right away, while several of the eggs waited in the refrigerator to be slurped up with ramen later in the week. Delicious!
Check back soon for Week 3, Phase Transitions – and our homemade ice cream lab!