Just some musing on my part on APO recipes that call for a 100C Sous Vide…
For the food scientists out there am I incorrect in thinking that most such recipes would perform nearly the same if run at, say, 2C lower/98C instead of 100C, with the benefit being to avoid altogether the risk of the energy hit of possibly boiling off some (or even all) of the water?
I’m not referring to the 2 small ‘c’ calories that’s saved per gram by lowering the temp from 100C to 98C, but rather the far more significant amount of energy that can be consumed during the “stall” at 100C due to water’s heat of vaporization.
By my reasoning potentially up to (but not necessarily) 542 small ‘c’ calories per gram can be absorbed at 100C with presumably no added benefit to the item being cooked, the equivalent of 0.6 kWh per kg weight of water. So why not run it slightly lower at 98C?
Water doesn’t just transition from liquid to gas at it’s boiling point. It evaporates at room temperature, but still requires the heat of vaporization (which changes with different temperatures) for any water mass that changes phase.
But to answer your musing; cooking at 98C or 100C should not to make much difference in the cooking time for the food. If you are using 100% steam, the difference will be even less.
What food are you planning to Sous Vide to 98C or 100C?
Many thanks, VeeTee, for your response but yes, was already aware of all of your points. My post was more a rhetorical one, proposing that most 100C recipes can be run at 98C in order to altogether avoid the significant energy cost of water’s heat of vaporization.
By using 100C as a target one potentially risks using up to, but not necessarily, 542 small ‘c’ kcals of energy per kg at water’s stall @ 100C, dwarfing the 83 small ‘c’ kcals spent in heating the water from room temp up to 100C in the first place. Of course the actual energy spent at 100C has much to do with how much energy the oven expends past what’s needed to just keep the oven from falling below 100C.
My post wasn’t so much directed at any specific recipe but was prompted after noticing that many of Anova’s recipes seem to take place right at 100C, one specific example being their Cajun Shrimp Boil (which, BTW, is excellent!)…
I actually don’t have any of my own recipes that operates near BP but perhaps will copy Anova’s Cajun Shrimp Boil recipe and adapt it to using 98C to put my own musings into actual action!
