Can someone explain to me what is happening on a molecular level when you don’t beat egg whites dry enough for incorporating into a chiffon cake and you end up with parts of the cake being custardlike (this doesn’t seem to be a problem with other cakes using whipped egg whites).  Also, how do you tell when the egg whites are whipped long/dry enough for a chiffon.  Thanks.

Chiffon cakes rely primarily on egg white foam (bubbles) for the characteristic cloud like texture.  Egg white bubbles are more stable (won’t pop as easy) when beaten to stiff peaks.  there is too much verbage to write to explain when this happens.  Instead, please use the recommended amount of cream tartar and beat away!  it is impossible to overbeat whites when cream tartar is used.  I beat till the foam reseembles rough dollops and mountains of snow rather than looking like whipped cream or frosting. Often, a big dollop gathers on the middle of the mixer’s whisk.

Also, be sure your whites are free from any yolks and your mixer bowl and whisk attachment are free from grease.  I always wash these in very hot water and dry with paper towels, just prior whipping.

Thank you for that very nice visual description, Hector! That’s really helpful!

Yes to Hector’s advice!

The thing that stabilizes egg white foams is the proteins unfolding (caused by the physical pulling of the whisk), then collecting at the walls of the air bubbles and linking with each other.  They form a sort of wire-link fence around each air bubble.  If you haven’t whipped them enough, your wire link fence doesn’t have enough links to contain the bubbles.

That said, I do wonder from your comment if there isn’t some other cause to your custard-y patches, such as underbaking or overfolding.  Are you using one of Rose’s recipes?

Hi Julie, thx for bringing the chemist in you.  I am just very sad when i hear from genoise, chiffon, or other sponge cake failures.

It only happened to me the 1st time and then I went overboard with whipping the egg whites so it wouldn’t happen again.  Definitely not underbaking as I tried baking it longer and it didn’t help.  That made me curious as to what was going on at the molecular level since I never had to be so careful with whipping egg whites in other types of cakes.  Any insight appreciated - thanks.