Sounds like a worthwhile day
Guessing that was at/via the local homebrew store?
Mixed opinions on fermentation length. Longer is most certainly safer up to a point so it's probably good base advice. Once you've done a few my personal take is that it's done when it's done and you can move on then.
There are basically two measures of done:
- The specific gravity has hit a terminal and stable level. The only way to know this for sure is to measure it, a wine thief makes this a smidge easier.
- The year has appropriately settled out (that is the beer is clear, or at least the year has dropped you can sometimes have other factors affecting clarity)
Happily these two things usually coincide so you can generally use the second as a proxy for the first (this is for your work-a-day ales; strong beers, lagers, and specialty like sours have slightly different rules).
If this isn't happening in a timely fashion (I claim two weeks or less as timely for most ales up to say 7-8%) you should look at your process. It's possible your yeast isn't healthy (vigorous initial fermentation, good flocculation), your temperature is of (to hot or to cold can both do it), or you have a contamination issue of some sort (not sanitized properly or something left in that's hurting the yeast or some infection from somewhere - you'll petty much always also notice this in the taste, although sometimes differentiating it from year stress can be hard).
The downside to leaving it to long is mostly threefold: oxygenated beer (mmm wet cardboard, minimize headspace, keep airlock full), possible dead yeast flavor (autolized yeast - not good unless you like marmite..), and increased risk of contamination (mostly mitigated by airlock maintenance - don't let it go dry, but also if you have a small bug problem your increasing the of they might be able to get a foothold.. hops also mostly eliminate this issue). Somewhere around a month on the original yeast is where you might start noticing some dead yeast flavor, and most of the other issues take a bit longer than that to really set in (except possibly contamination but then you already had a problem so....).
It's generally also worth being more conservative and waiting longer if you're bottling because bottle bombs are bad!! But even then I'd recommend taking gravity reading because you can have a stuck fermentation and if it restarts in the bottle it can be a little exciting!! In kegs you mostly have flavor/appearance issues if you get to far ahead of yourself.
As a side note, I don't actually rack any of my beers to secondary unless they're a strong beer (or some sours) that's going to sit in the fermenter for over a month. After some research and tests (and mostly reading an excellent article in byo magazine that kicked off the idea a few years back) the downsides way outweigh the upsides. Basically you're exposing your beer to more air, more risk of contamination, and doing more work. The payoff is that is slightly easier to not pull over any yeast ( and since I go straight to keg, meh!! If the first pour has a smidge of yeast in it no big deal).
I thought I'd mentioned this before but can find no evidence to support having done so so at the risk of repeating models.. If you haven't read it yet it's worth a quick perusal of John Palmer's online book "how to brew" (
http://www.howtobrew.com). It's not super technical but it'll get you through your first few dozen batches well enough and lays out the basics in a nice clear way (as well as not having any major errors of fact that I know of). I generally suggest folks read chapter 1, but make the beer using the process from chapter 2 and on. Adding some grains in addition to the extract does a lot to support yeast health and will make a much cleaner "fresher" tasting beer.