What’s the science behind baked Alaska?
As you’ve no doubt guessed already, meringue is a terrific insulator. It’s made of thousands upon thousands of tiny bubbles, and each one of them works like a little air gap, slowing down the transfer of heat from the oven to the ice cream. Still air, you see, doesn’t move heat very well.
Thus meringue is great at putting the hammer down on convective heat transfer, i.e. movement of heat via air flows (or liquid flows). It’s not so good at preventing the other two major modes of heat transfer: conductive (objects of different temperatures in physical contact with one another) or radiant (electromagnetic radiation). The good news there is that most of the heat transfer that occurs inside a home oven is of the convective kind. Clever fellow, that Rumford guy.
With all this talk of Baked Alaska, i’m beginning to think you actually put it in the oven! I’ve made a few of them and I just hit mine with a blow torch. Maybe that’s why in Australia we call it a Bombe Alaska….
Blowtorch?? It’s not TORCHED Alaska, it’s BAKED Alaska! 😉
Hehe…yes I’ve seen it done that way, but to my mind it doesn’t have the same drama. Nor does it create the same all-over warming effect of the meringue. But I guess if you want real drama you douse the thing in brandy and set it on fire. I’ve seen it doe that way, too.
Just thought to check another list’s archives and found this, suggesting that perhaps accounts of Rumford’s experiments were known second hand:
– In Lee Edwards Benning, The Cook’s Tales: Origins of Famous Foods and
Recipes (Old Saybrook, Connecticut: the Globe Pequot Press), 1992, p.
79, we have:
“There [in 1895, at the Hotel de Paris in Monte Carlo] the Surprise
Omelette was being served by Jean Giroix, who attributed its creation to
an American physicist by the name of Benjamin Thompson, Count Rumford
(1753-1814). But this was no ordinary pastry-encrusted block of ice
cream such as the one served at the Grand-Hotel nearly three decades
before. This was the offspring of a wonderful marriage of science and
culinary art. Now the ice cream sat upon a base of sponge cake and all
about it was, not a crust, but a coating of thick, golden-brown
meringue. Experiments in thermal conductivity, based on those done by
Count Rumford, had proved that egg whites were such superb insulators
that even while browning, they could keep ice cream frozen.”
Bennings goes on to discuss the “dish’s most famous name, Baked Alaska.” –
It’s interesting to note that though a number of bios exist on Rumford, none mention meringue, not even his own collected works:
http://books.google.com/books?id=qhN-vsjk81YC&pg=PA308&dq=%22COunt+Rumford%22+insulation&hl=en&ei=OY4YTo-TD9PdiAL2urjSBQ&sa=X&oi=book_result&ct=result&resnum=4&ved=0CDcQ6AEwAw#v=snippet&q=baking&f=false
As with a number of culinary legends, the tale is found ONLY in culinary works, not works which address the key subject in a more general way. Which, authenticity-wise, is a bad sign.
Your research is invaluable as always, Jim! This is terrific stuff. Many thanks.