When I tell people I brew beer, the most common question they ask is "How long does it take?" (Closely followed by "Like in your bathtub?" or "So basically like
Breaking Bad?") It's a difficult question to answer since it can mean several different things: How long does the brewday take? How long does it take before the beer is ready to drink? How much time do you spend on a single batch of beer? On top of that, it can vary from batch to batch. That's a bit much to cover to answer a casual question, so if you're interested here's the full explanation.
Preparation:
In terms of total time spent, maybe the longest stage of brewing is the preparation. Researching the style (both in books and bottle), writing the recipe, outlining a process, more research. However, it's not really fair to include all the time I spend daydreaming about beer at work. If I could get paid by the hour for time I spent researching (and writing about) beer, I could quit my day job. And all that doesn't even include time spent running to the homebrew store to pick up ingredients or making modifications to equipment.
Brewday:
This is what people most often think of when they think brewing--a giant boiling vat of mysterious ingredients which, under the bearded alchemist's watchful eye, transforms into that golden elixir we love so much. In reality it's mostly cleaning. Start to finish, brewday takes me about 8 hours for one batch. The breakdown is roughly 1 hr of setup, 1hr to heat strike water and continue cleaning, 1 hr for the mash, 1 hr for vorlauf and sparge, 1 hr for boil, 1 hr for chill, and two more hours to rack to the fermenter and cleanup. If I time things right, I can get another batch done with only a couple hours more, but this requires careful planning and that everything goes according to that plan.
Now that is of course only for my standard procedure. Other brewers may do things differently: more involved mashing regime, longer boil, more or less time cleaning, etc. If someone were to brew a Czech pilsner for example, the triple-decoction mash and 90 minute boil that are required when dealing with under-modified pilsner malt would both extend the brewday. I use pure 02 to oxygenate the wort, but some homebrewers shake the wort or bubble air through it until they believe there is sufficient oxygen dissolved to support healthy yeast, maybe a 30-minute addition. On the other end of the spectrum, extract brewers can skip the mash and sparge, going directly to the boil, effectively cutting the brewday in half. There are a lot of variables to consider, but each brewer tends to find a rhythm in his brewery, and for me that 8 hour mark is a fairly good rule of thumb.
Fermentation and Conditioning:
Once the yeast are unleashed, the rest is mostly up to them. There's not much for a brewer to do besides manage temperatures and keep from screwing things up. It takes less than a week for the yeast to complete fermentation, converting all the sugar they care to digest into ethanol, carbon dioxide and a host of flavor components.
But at that point, the beer is rarely ready to drink. The yeast often takes a few days to settle out, maybe it needs time for dark malt flavors to come together or fusel alcohols to mellow, maybe it needs time to lager, or maybe there is time set aside for dry-hopping. It depends on the style of beer, but for something best fresh like a wheat ale or IPA, two weeks from brewday to packaging is fairly reasonable, lagers need roughly a month, and big stouts and barleywines can take up to a year.
Packaging:
The final step before a beer is ready to drink is packaging. With modern force carbonation techniques a keg can be ready to drink in as little as 24 hrs. On the other hand
bottle conditioned beers take roughly 3 weeks to naturally carbonate in the bottle. These are the two methods I practice, but there is all sorts of other middle ground with cask ales and force carbonated bottles falling somewhere in between.
Personally I tend to keg my low gravity, everyday beers since it is the quickest and easiest solution, requiring maybe an hour of brewer time to clean and sanitize equipment and take all the necessary measurements before siphoning over to the keg. It's the kind of thing I can do on brewday while waiting for water to boil. However if I brew a bigger beer that I shouldn't be drinking as frequently or something special that I want to horde, I will put that in bottles. On the homebrew scale, bottling is a huge pain. It often takes me an entire day to clean, sanitize, and fill each bottle individually by hand. It is probably the single task I dread the most in the entire process.
Conclusion:
So when you put that together what do you get? Well start to finish, a beer can take anywhere from two weeks to a year to complete, but usually somewhere around four weeks. However little of that time is spend actively brewing the beer. Brewday takes me about eight hours, tending and packaging somewhere from two to ten, and "research" is always an ongoing process. Most people quickly realize this is more trouble than it's worth to brew their own beer, but for some of us obsession seems to justify any investment of time.