Does longer brewing time with hot water negatively effect flavor? I've been reading the answers to related questions, but I'm still confused about the variable of the length of brewing time. I've heard that when using a Moka pot, one should turn off the flame immediately upon hearing the very first gurgle sound because if it brews a little bit longer (before the pot starts spurting coffee) the resulting liquid coffee can taste more bitter. I've also read that one of the benefits of the Aeropress is that the "brewing" time is so minimal that the coffee tastes better and is "cleaner". If less brewing time=less bitter,then does coffee made with a french press inherently taste more bitter than other methods? (Maybe people that use the french press prefer more bitterness?) I also read a post elsewhere from a person who says she bought a single-cup coffee filter holder with three holes at the bottom rather than the typical one hole, and that the coffee tasted better because the water drained more quickly. Does the faster the coffee passes through a filter make it less bitter? If so, I wonder why the three hole filter holder isn't more sold more frequently. The art of coffee brewing can be so mysterious ;/
As discussed further in this question about bitterness, degree of extraction is one significant factor in bitterness in your cup. There are a couple of other links to coffee bitterness in that question also.

Keeping other major factors constant (e.g., same temperature of water, same beans), time and grind level are the easiest to modify to reduce bitterness. That is: shorter time and coarser grind will (generally) result in less bitter coffee. While you certainly can't expect to get a reasonable brew from barely chopped beans in 15 seconds, small changes in time and grind level can have a noticeable impact on outcomes, especially for immersion-style brewing methods like French press, Aeropress, pour-over, and to a lesser extent stovetop methods like percolator or moka.

Specifics vary by brewing method. For instance, some bitter-tasting compounds are filtered out by paper filters, so paper-filter pour-over will generally be less bitter than French press, for example. Also, your average paper filter will allow brewed coffee to filter more quickly with a coarser grind (finer grinds will more quickly clog the filter) so you might have to vary your pouring method to keep the total brewing time constant.

You might enjoy trying to vary one parameter at a time: trying coarser- or finer-grind coffee, then with a shorter or longer period of time, in both cases trying to vary only one parameter at a time.