No boiling. But all equipment is sterilized (chemically) before use.
The mixture of apple juice made from the concentrate ferments for about a week, till it settles down, then when it is bottled, 1/2 a teaspoon of sugar is added to each quart bottle before it is sealed. That ferments under pressure and gives a great fizz when opened and drunk after a bout a two week wait.
One doesn't want to start with too sweet a mixture of apple juice nor to add too much sugar. A low alcohol content is pleasant, too much would make it too wine-like and would probably produce too much pressure in the bottles).