There are times when you come across a new recipe that instructs you to treat eggs in a special way rather than just crack them open and toss them in. There’s a good reason for that, sometimes a batter will be too heavy for the whites (and it will collapse them) or maybe a mixture is too hot to incorporate the egg without cooking/scrambling it (but it needs to be added right now).
Since these techniques are typically used infrequently, it’s easy to forget just what is required. Here’s a handy tip sheet that you can quickly refer to and keep things moving along.
- Slightly Beaten: Mix with fork just enough to blend both whites and yolks.
- Well Beaten: Beat whole until light and frothy.
- Yolks, Well Beaten: Work at them until they are thick and light colored.
- Whites, Beaten Stiff: They are done when they stand in peaks when mixer is lifted out. Points of peaks droop over a bit and the surface is still moist and glossy.
- Whites, Beaten Very Stiff: Peaks will stand upright without drooping when mixer is removed and surface looks dry.
- Fold Into Beaten Egg Whites: It is usually recommended that a heavy mixture be folded into beaten whites rather than the other way around as less air is forced out of whites in the process.
- To Fold: Gradually add mixture to stiffly beaten whites with up, over and down movement of spoon or wide rubber or plastic scraper. If instead the mixture is stirred into them, air is driven out and the whites will collapse.
- Add Slightly Beaten Yolks Or Eggs To Hot Mixture: Always blend a few spoonfuls of hot mixture into yolk before stirring into remaining hot mixture. Egg will blend more evenly and won’t lump or curdle.
When whites won’t stiffen:
- Make sure there is no trace of yolk or fat until fully stiff. One good habit to get into is to pour a bit of vinegar on a paper towel then wipe down the inside of the bowl (and whisks/beaters too). This will remove any trace of grease or soap that may be lingering. Wait a few minutes to fully dry then get started with whisking.
- Use very clean tools! Use glass, stainless steel or ceramic bowls rather than plastic since the plastic can retain traces of grease. Copper bowls come highly recommended for this job (just don’t add anything acidic like Cream of Tartar).
- Try adding a pinch of Kosher salt.
- Humidity can affect the results so rainy days may not be your best option.
- Add a good pinch of Cream of Tartar, it will help stabilize them and make them sturdier to work with. A good rule of thumb is about 1/2 tsp per cup whites (test for your preference; can increase/decrease as you wish). No Cream of Tartar on hand? Try a bit of freshly squeezed lemon juice (just a bit will do the trick).
Eggs separate easier when cold so do that right when you take them out of the fridge. If the dish you are making requires room temperature egg whites, still go ahead and separate them then set on the counter for about 15 minutes or so before using.
If you do have some “mistakes” with traces of yolk, don’t toss them out! If you can’t use them to cook with in the next day or two, freeze them for future use. See this page  for details.
Also see 101 Cookery Terms  for more neat-to-know Cookbook Lingo.