Q&A for How to Pasteurize Your Homemade Wine

The alcohol (ethanol) will evaporate at around 78°C. While some will evaporate, the alcohol vapors will condensate in the bottle and drip back into the wine. It won't be a problem unless you remove the foil seal before it's finished cooling.

It was about the temperature - 60°C will need 30 minutes, 72°C will only need 15 seconds.

Heat the juice to about 70°C (158°F), stirring frequently. Keep it at 70°C for at least 1 minute. This will make sure that all E. coli bacteria, as well as other organisms such as mold, are destroyed. Pour the juice into clean, sterilized preheated bottles.

Not likely, although it may help things settle out more quickly as it will stop fermentation and the small currents that form in the liquid from fermentation. However, I am no expert in the matter.