Egg white protein coagulation

[JAZ]

While it's true that I don't make a lot of drinks with egg whites, I do make Clover Clubs fairly often, usually with fresh berries but sometimes with (homemade) raspberry syrup. I don't usually take the trouble to "dry shake" but just shake once. I get enough foam for my taste although it's probably not a professional result. This Thanksgiving, though, I made Clover Clubs twice; both times the egg white simply coagulated. No foam, just stringy bits of protein. The eggs were fresh, and I didn't do anything differently from my usual method. Has this happened to anyone else? Can anyone explain what might have happened?

[Shalmanese]

Do you have any acid in there. Too high a concentration of acid will denature proteins.

[J. Williams]

I've had the same problem, and it's infuriating! I've been able to minimize this by using VERY fresh eggs and adding the whites last, but still, I run into this issue on occasion. Dry-shaking doesn't help with this. The amount of acid doesn't seem to matter (much).

Here's hoping someone has a better answer than "always double-strain."

[JAZ]

There was acid in the drink, but as I mentioned, it's a recipe that I make all the time, and the acid level wasn't any higher than when the drink works right.

[slkinsey]

Acid does promote curdling of egg whites, but eggs actually become more alkaline as they age.

[vice]

Might the order you added the ingredients to the tin have been different from usual (i.e., citrus + egg white before gin vs. citrus + gin before egg white)?

At what pH do egg white proteins coagulate? Is it common to see lemons acid enough to coagulate egg white even when it's added last?

[DLim]

I'm pretty sure a single type of fruit (raspberries, or lemons for instance) can vary significantly in acidity between specimens (and batches). At work, we've long had a problem an inconsistent texture in a gel made from agar, lemon, and ginger, and I think it is because some batches of lemons are more acidic than others, which changes how the agar behaves. pH testing would be the way to find out for sure.

Of course this could be totally wrong or totally irrelevant to your problem.

[Frederic]

Acid does promote curdling of egg whites, but eggs actually become more alkaline as they age.

Acid also helps the foaminess, but it is a fine balance. Too little and there's not much of a foam(egg protein does not denature to form bigger matrices), and too much, and the foam breaks down (breaks up interactions between egg proteins).

Same with shaking. Too little or too much agitation is bad.

Some notes from the Eggpire Strikes Back talk at Tales of the Cocktail:

http://cocktailvirgin.blogspot.com/2010/08/notes-about-eggs.html

[Chris Amirault]

I think an experiment is necessary using older vs newer eggs.

[EvergreenDan]

Maybe it does have to do with proof. I've never had this happen before (although I don't use egg white often). I made a Tuesday with Mole, double batch, with 1 large egg white. I had to sub 151 Goslings, so the proof was higher than expected. I did add the egg white last.

The coagulation is unappealing. Probably should have tossed it, but I used some very good cognac in it and I just couldn't. Taste was fine. Texture was a bit slimy (as it didn't foam up as expected). Coagulated egg white was very fine and not particularly noticeable as solids, but just mouthfeel and visually, of course.

... not as mellow as I had hoped to be ...