Of all the things I get questions about, none surprise me more than questions about bottle conditioning, and not because it isn't important (it is): because it's not something I've ever struggled with.
I understand why people freak out about it a little, of course. After all, it comes at the end of the process, you've put a lot of work (and wort) in, you have high hopes. You add your priming sugar, cap that sumbitch, and wait. Time passes, you chill a test bottle, prep your favorite beer glass, reach for the bottle opener aaaaaaaaand.......
Nothing. No puff of escaping air. Your heart sinks. Your ego deflates. You pour, knowing even before you do that it's going to be a flaccid affair, and sure enough there's no carbonation, no fluffy whiteness. Just a sad little collection of not-quite-foamy bubbles from CO2 being slapped out of suspension as you dump beer aggressively into the center of the glass hoping for anything resembling head.
But it doesn't have to be that way. Below is a brief description of my bottle conditioning process (from Beer #1 to today, ten years exactly since that first beer) and a few quick Q&A responses from e-mails I've gotten from readers and homebrew club members.
Weight, weight - Don't Tell Me
First off, my process. It's pretty simple, really.
First, I check my beer's finishing temperature; a colder beer will have more CO2 in it already, while a warmer one will have blown more off.
Second, I head to my favorite Priming Calculator website (this one). Why that one? It was the first one I tried, and it worked, so why screw around? All you need is the volume of beer you're carbonating (which you should know already), the temperature of it (which you just checked), and the volumes of CO2 you want (which you should decide based on your recipe, but somewhere around 2.25, in all likelihood). The result is a weight. Don't just use that whole "PRIMING SUGAR" pack from the kit. Always carbonate by weight.
With that info in hand, I head to the kitchen and add the given weight of sugar (dextrose if I have it, table sugar if not, and I've never noticed a difference in the finished product) to a cup or so of water, stir, and bring to a boil for about a minute.
After that, it goes into the bottling bucket. I rack onto it, and that's it. No stir or anything.
I bottle and cap, and then set them aside for about a week. Usually seven days is plenty. The longest I've ever had was about three weeks, but that was very much an outlier (and even she carbonated up for me, eventually).
Your Questions (well, someone's questions...)
Do you ever add yeast at bottling, to help out the existing yeast?
Nope. Never. Not once. Not even for a several-month-old Eisbock that clocked in at about 14% ABV. Yeast are incredible. If you're not getting carbonation, it almost certainly doesn't have anything to do with whether there are yeast in there capable of carbonating - if you haven't filtered them out, then they almost certainly are.
I didn't get carbonation. What should I do?
Step one is put your bottles someplace warmer. In at least 9/10 cases, that does the trick, and a beer that sits for a month in a kind-of-cool place might not carbonate, but one that sits in a slightly-warmer place might carbonate in just a couple of days. I find 68F to be the lower limit. Find a warm spot in your house (near the dryer, in an upstairs bedroom that gets a lot of sun, etc.). In a real pinch, set your beer on top of a heat register or near a baseboard heating element.
If that doesn't work, try rousing the bottles and applying heat as above.
If that doesn't work, check your scale/calculations: maybe you didn't add the right amount of priming sugar.
Should I try adding more yeast to each bottle?
It almost certainly can't hurt, but it's probably unnecessary, and you're exposing the beer to oxygen. I'd let time/temperature take a shot at it first.
Should I add more SUGAR to each bottle?
NO! There's a real risk of bottle bombs if you do, and that's no joke. Flying glass is something to be avoided, and even if you don't go THAT far, you might still end up with a bunch of gushers.
Honestly, before you take that step, just consider drinking it flat or using THAT beer for vinegar or cooking applications.
Have you ever tried the Carbonation Tabs/Pellets?
Once, and I got pretty uneven results. It's kind of a pain, but the short-boiled sugar solution option I describe above seems like the best method.
Do I have to use white sugar?
No, you don't. You can carbonate with maple syrup, honey, candi sugar - virtually any simple sugar. You might need to experiment with weights/volumes, though, and keep in mind that some sugars will add flavor in addition to CO2 and a little alcohol.
What about caps?
I recommend them. Otherwise the beer slops all over the place as you ride your bike to the party.
Seriously, though, any caps are probably fine. Pick a color you like. If they're available and you want to be super-careful, go ahead and buy the oxygen-absorbing caps. But make sure you seat them fully on the bottle - even a slight gap can let air be pushed/pulled in and out as the temperature in the bottle changes, so don't just crimp them until you can hold them upside-down without liquid leaking out (though it's a start).
Why do you bottle at all? KEGGING, BABY!!!!
I keg, too, but I like bottling, especially for things I'm going to age for a while (Barleywine, Old Ale, etc.) and sometimes my brewing outpaces my keg supply. If you do it regularly, it doesn't even take all THAT much longer - I bottle a batch in about an hour, two batches in about 90 minutes, three in about two hours.
Personally, I like that once I put that cap on, it's done. I don't need to worry about a gas leak, or a contaminated keg wrecking my entire batch, or something in the draft line/faucet screwing up my pour. Bottle conditioning is reliable as hell, and that's worth a little time once in a while (if not every time).
In Yeast We Trust
I've said it before: yeast are incredible. They're worthy of your trust. Give them the right conditions, and they'll probably take care of you!
But I meant what I said back there: dump it before you add more priming sugar. It's not worth a glass sliver in the eye. The more you know...
Keep it simple.