I have some questions which I couldn’t find any answer. I’m hoping that to find an answer to clear these doubts.

Q1: why is it that when egg whites are beaten on its own or with sugar, after about 4-5 minutes, it will change to dry stage (lumpy and loses its gloss) whereas when beating heated egg whites (for swiss/italian meringue), it will never change to dry stage? In fact, I can beat it until more than 10 mintues and there won’t be any problem with it?

Q2: when beating whole eggs for sponge cake, does it mean that the longer I beaat, the more stable the mixture will be? will there be a time whereby the mixture will collapse and loses air?

Thank you so much!

When you beat whites, as they foam, the proteins unwind (think of them as curls of thread if you will) and begin to form a “web” (for want of a better word) - the threads begin to straighten out and bond with other threads. The webbing is trapping air in the form of bubbles, and as the foam begins to get firmer, the webbing becomes more like netting.  But at some point, you have too many threads and the netting collapses - which is what happens when the whites are overbeaten and become dry and blocky.

Adding an acid helps to prevent the webbing from getting out of control (e.g, lemon juice, cream of tartar or even sugar, although if you wait too long to add the sugar if you are not using an acid, you can overbeat the whites.).  If you denature the whites by heating them (as for swiss meringue), this also helps to prevent the whites from getting overbeaten.

When beating whole eggs with sugar (going for the ribbon stage) I’ve never overbeaten them; I have a flourless chocolate cake recipe that calls for beating whole eggs and sugar for 20 minutes before adding the chocolate and the biscuit recipe we use has whole eggs, yolks and sugar and we end up beating that for almost the same amount of time and it’s also never been overbeaten.

Hi Jeanne,

Thanks for the tips!

I have added sugar to the white while beating (added after it turned frosty), but after sometimes, it turned dry and blocky. However, when I beat whites with heated sugar (for italian meringue, whites are warm), no matter how long I beat (maximum I go is 15 mins, way beyond what I normally beat, ie. below 4 mins), the whites will not turned dry and blocky.
That prompted me to ask: does heat really matters in beating egg whites? can we omit things like cream of tartar, lemon juice so as to prevent the whites from turned dry? will there be a stage whereby even after 1 hour of beating, the whites still won’t turn dry?

FOr whole egg beating, I beat to the stage of stiff peak, after ribbon stage, it still came out risen, it doesn’t collapsed. and I noticed that no matter how long I beat, it doesn’t collapse.

I’ve found that when you are beating whites and adding sugar (no heat applied) you can overbeat them even if you add an acid (cream of tartar or lemon juice) and even when sugar is added after they are foamy.  This is because the netting - all those loose threads are bonding and it becomes too “solid” after such a long time beating.

With Swiss Meringue, the whites and sugar are heated until the sugar dissolves and this denatures the proteins in the whites so they don’t behave the same way when they are beaten and don’t get blocky and dry.

wow, thats quite a bit of science there!

I guess when the heat is gone, it probably will turn dry and blocky?

Not that I’ve seen; when you make Swiss meringue buttercream, you whisk (by hand) the sugar and whites over a bain marie until the temp of the whites is 160; then you put it on the mixer and beat until it has tripled in volume and then you add the eggs.  There’s no reason to continue beating so I don’t know if you can over beat this mixture or not.  The percentage of sugar in the whites is high so that might offer more protection but I’m not sure.