1. Going from extract to all grain BIAB. I made this change very early on in my homebrew career and never looked back.
2. Switching from carbon filtered tap water to an RO system and building the water profile to style. I made this switch about 6 months ago and the results have been astounding. Our tap water here in the Denver area isn't bad for homebrewing, but it's not perfect for most styles. Before the switch, I noticed that all of my beers were starting to taste alike and bit "meh". Getting an inexpensive RO filter has been a game changer. Hard to explain, but the flavors just pop more for each style. I'm still experimenting with profiles for certain styles, but I'm convinced that this one change has taken my brews to the next level.
2. Switching from carbon filtered tap water to an RO system and building the water profile to style. I made this switch about 6 months ago and the results have been astounding. Our tap water here in the Denver area isn't bad for homebrewing, but it's not perfect for most styles. Before the switch, I noticed that all of my beers were starting to taste alike and bit "meh". Getting an inexpensive RO filter has been a game changer. Hard to explain, but the flavors just pop more for each style. I'm still experimenting with profiles for certain styles, but I'm convinced that this one change has taken my brews to the next level.