Eggs

Coagulation
Coagulation of egg whites takes place at around 60-65°C and yolks at around 65-70°C. Mixing eggs with other food products can change the temperature at which this happens. Adding sugar, for example, raises the coagulation temperature, while adding salt lowers it. Adding liquid (e.g. milk or water) to eggs dilutes the concentration of proteins and as such increases the temperature required for coagulation to take place.

Whisking/Beating of Egg Whites
Beating egg whites changes their texture and the best way to achieve a light, yet stiff result is by using a balloon whisk to beat them at room temperature. The act of whisking incorporates air into the mixture, resulting in soft, medium or firm 'peaks'. Soft and medium mixes are used for 'foamy' type foods (e.g. soufflés) while firm mixes are predominately used for meringues. Whisking eggs too much will result in granulation and dryness.

Once beaten, eggs should be used immediately to prevent them from losing air and becoming watery. Most recipes call for beaten egg whites to be folded into a mixture at room temperature, since adding them to a hot mixture will cause them to collapse.  Beaten egg whites can be stabilised with the addition of a little acid like vinegar, lemon juice or cream of tartar.