Don't let the naysayers talk you out of it. I recently started making a couple 1 gallon batches and they're fun!
First of all, I brew outside, and don't have a garage. Some of my gear is in my basement, and some is in the shed. By the time I get everything set up, brew, cleaned up and put away, I've invested almost 6 hours. Because of this, I can't really brew during the work week, which only leaves the weekends. Weather can scrub out brewing on the weekends since I don't have any cover.
I started using the Brew in a Bag method that I first read about here
. It seems to work very well, and I have everything cleaned up and in the fermenter in under 3 and a half hours inside on my stovetop. It seems to require a lot less babysitting than a full batch, so I can do other things while it's mashing and boiling. It will probably only take an investment of around $6 to get started.
When I brew my next one, I'll document it and put it on my web page. Until then, here are some thoughts.
Set your oven to around 150, then when you mash in, move your pot into the oven to keep temperature.
Think about getting a refractometer to measure your gravities. With a 1 gallon batch, you'll notice the ounces that you use for a hydrometer reading.
I have been using the foam control drops to squeeze as much into the fermenter as possible without having a blowoff problem.
If you're careful, you can probably get around 8 bottles out of a batch.
If you're planning a full-size batch of a big beer or a lager, brew a 1 gallon batch of the same beer. You'll have a starter that you can drink!
Interested in trying a step mash? You can change the mash temp very easily/quickly with a one gallon batch, by direct heat.
Like I said, the next time I brew a 1 gallon batch, I'll document it.