Note: In all of my following comments, your mileage may vary! They are opinions only!
jfliv said:
1. How long before I can drink my beer (more to the point, how long until it is no longer considered "green")?
Like most things in life, "It depends." Depends on the style, the conditions in your brewery, the procedures you've adopted for your brewery, etc. For example, a low-gravity, English-style Ordinary Bitters can be fermented to completion in three or four days, racked to a cask (with finings and priming) and served a week to ten days later. Turnaround? 14 days. On the other hand, another English style, Barleywine, can take weeks to ferment and months of aging before it becomes palatable. Another example: Pilsner. Same sort of gravity, bittering, etc. as Bitters (that's a simplified example!), but must be stored for weeks before packaging.
Shortly, there are myriad variables to be considered, not the least of which is your experienced palate - you must taste each sample you take of your beer during its brewing cycle, from kettle to glass. Each gravity sample, at racking time, at packaging time. Take notes. Eventually, you will discover that point where each recipe comes into its own, and can more readily plan.
2. When is the optimal time to drink the beer? (When should I brew for that special occasion?)
IMO, that's so closely related to #1 that I'll simply refer you to my above comments.
3. When does aging go from a good thing to a bad thing? (How long can I store my beer?)
I think the answer is complicated for these things, and has to do with the different types of beer. For instance, IPA is designed to preserve well...using hops and alcohol to fend off nastys. However, smaller, less hopped beers may be more susceptible to fouling. I'm not sure if this preservation effect also slows desirable maturation.
You're 100% right - it
is complicated, due to the wide variety of variables. Aging alone isn't necessarily a bad thing; all beer does well with a bit of time to consolidate flavor after the period of vigourous fermentation ceases. Judging that length of time really can only come from experience.
Commercial breweries - even respected microbreweries - can have a beer like a 6-7% ABV IPA from brewkettle to your glass in 14 days. And it tastes fabulous! But their processes are quite different from ours. Let me illuminate one process: filtration. Once you sterile-filter a beer, stripping out the yeast, you essentially remove any possibility for the beer's flavor to change (except chemical staling, but that's a bit too complicated for this post), because in removing the yeast, you've stabilized the beer. Once filtered, force-carbonate to ~2 volumes and package. Ship it out and tap it. It is the rare homebrewer who filters his beer. Hence, our beer is never quite stabilized, thus its character changes over time.
Style also has something to do with it. You can brew a beer like Belgian Wit and really
ought to have it gone within a couple of weeks. You can brew a Barleywine and cellar it for a decade.
For me, the most important flavor I learned to recognize was
freshness. That's hard to learn, but very much worthwhile, because - once you've learned to recognise when the beer was "ripe" or no longer green - you must now learn to recognise when it's stale. The best method is by drinking lots of beer. "Damn!" I hear you shout. "Not that!"
Try it with a nice Witbier. Either make some or purchase some, carefully checking the dates on the package. Better yet, make some of your own, then buy an assortment of domestic and imported examples. Set up a blind tasting and sample them all. I can all but guarantee you'll find the best-tasting example is the one that's been in the package the least amount of time (considering bottle-conditioning vs. force-carbonation)!
Better yet, buy a sixer of Hoegaarden just before you get on the plane to Belgium, then taste the bottled import next to a fresh draught as close as you can get to the source. The difference is dramatic.
In any case, I was wondering... are there rules of thumb? Are the rules different for bottle/keg/Cask?
My only rule of thumb is to listen to my beer. I take daily gravities when it's in the primary, graphing the ferment. I always taste the sample, write my notes, then compare them with previous batches (I tend to brew the same dozen recipes, with few trips afield, in case you can't tell!). From there on out, it's a judgment call made on experience. There are few rules, of thumb or otherwise, to guide you.
Do I rack it? Dunno. Is it something that needs to be racked before it can be packaged?
If I racked it, how long do I keep it under an airlock? Dunno. What have I brewed before that's like the beer in question? What do the guys on HomeBrewTalk say? What do my books tell me?
Do I package it instead of long bulk aging? Dunno.
Et cetera, et cetera, et cetera. All these things are best answered by experience tempered with judgment and good old common sense. Another example - I know the last brown ale I brewed tasted wonderful with a month in a carboy in my basement. That was in December, where the basement was, on average, 60 degrees. Now it's June. A variable has changed (the basement's ambient temperature), making it impossible to
know that I can replicate the previous beer. So I must make a judgment call. That's a SWAG - Scientific Wild-Arsed Guess.
One of the wonderful things about homebrewing is that our beer is a living creature that can do surprising things, no matter how we try to split hairs. You gave a really good example in your post:
One of my worst beers ever was a nut brown ale, which I tasted 8 weeks after bottleing (bottle conditioned). Turns out one of my best beers was the same nut brown ale, about a year later (when I ran out of every other kind of beer, what a nice suprise it was)...
That's part of the experience-building, which makes later judgment calls easier to make - okay, maybe not
easier, but certainly with more confidence.
I've blithered enough. I hope that, somewhere in the above quagmire of no definitive answers, you've found something useful.
Cheers,
Bob