I'm not too sure about the time in the primary. I think the instructions say, 5 to 7 days. It is all about the specific gravity the recipe calls for,,right??
Well, it will probably be about finished fermenting in a week- but the beer won't be "done" by a long shot.
Even after the active fermentation is over, the yeast are working. One of the things they do is digest their own waste products, when they run out of sugars to eat. After that, they begin to clump together and fall out of suspension, falling to the bottom. That means the beer will become clearer and less yeasty tasting. If you're going right to a keg, I'd suggest waiting about three weeks before kegging. For people using a secondary, the beer can be moved there to clear and condition some.
Even though it's possible to carbonate beer that's only a week old, it generally is better to give it a bit more time. For most beers, I like to keg them when they are about 4 weeks old, then allow them to condition at room temperature for a week or two, then put them in the kegerator to get them cold and ready to drink.
One of the reasons some kit instructions say to ferment for a week and then bottle is to sell the kit. I mean, if the package said "Ready in just 6 weeks!", not too many new brewers would jump at it. But that's more realistic, and gives better beer.
