Carbonating while a beer is in a bottle, also know as bottle priming or conditioning, is the most common carbonation method for beginner homebrewers. But also many experienced homebrewers and commercial breweries utilize this technique as well.
The main challenges of counter-pressure bottling are to retain the beer’s carbonation and minimize its exposure to oxygen during the transfer. When performed correctly, almost all of a beer’s carbonation is retained when it is counter-pressure bottled. Likewise, with a little practice, the beer can be transferred with minimal exposure to oxygen. Learn how with pointers found here.