How do low volume boils affect the taste of beer?

What is the primary difference in taste between doing a full boil versus only a 2 gallon boil?

As far as I know, the your low volume boil will produce a less bitter beer, because you will get reduced hop utilization due to the high gravity of the wort.

When I did a partial boil, I used late-extract addition in order to help offset this.

I'm still a noob, so I'm sure someone else will have a more definitive answer.

There's also a much higher chance of the sugar caramelizing - due to less space and a thicker wort - which will cause the dreaded "homebrew funk". This is perceived as a strong bitterness or tartness, which especially hits me in the back of the throat. It diminishes over time but can dramatically change the flavor of a beer within the first couple months.

you will definitely get lower hop utilization, but i don't really like hoppy beers so i just shoot for the middle of the range and it works fine.

i do all my partial mashes with partial boils...that's the idea for me, to minimize mess, make for easy pouring (i gotz a bad back) and shorten the brew day (my stove takes a long time to boil large quantities)

i never heard of the "dreaded funk" and i often will do longer boils to get some carmelization out of the brew. some recipes i've seen even call for it. not sure if it's possible, but my brews have been fine.

i generally boil 3-4 gallons and add my extract at the beginning of the boil. must say, the last few batches especially with my new "tea-bag" method have turned out fantastic!

Homebrew funk is not from doing a partial boil. Its from making bad beer! As noted above your hop utilization will go down but you can compensate for that and you will get some kettle caramelization. 2 gals is really pushing it though so you might consider investing in a canning kettle (they are cheap) that will hold 3-4 gals of boiling wort.

GT