Is it Safe to Carbonate Beer in a Can?

Question

I have been thinking of getting canning equipment for my homebrew set up to make it easier to share beer ( no worries about collecting my swing top bottles down the line). The only question I could find relating to carbonation methods for canned beer was this question, Beer Bottle vs. Can Head Space, Carbonation, and Conditioning. I would prefer to "can condition" for convenience, though I do have a keg setup to force carbonate prior to canning. My question is, are there any dangers to naturally carbonating in a can?

Answer 1

I am the guy that asked the question you referenced. Since asking that question, I have canned 500+ 16oz cans of beer and session mead/melomel. I notice that it has only been a couple of months, which makes the number of cans seem a bit excessive. In my defense, I had six buckets of mead that I started last summer and finally got around to packaging, and my daughter asked me to supply the beer for her wedding next month, so I have been brewing pretty aggressively recently. And I might have been drinking a few myself :-)

All of my cans so far have been can-conditioned. I would highly recommend it. I follow exactly the same routine when canning as I do when bottling. If know what you are doing and you don't get bottle bombs, you will not get can bombs either.

My experience with canning has been very positive, and a step up from bottling:

1. I sanitize by filling and emptying in Star San in a bucket. With bottles, it takes a long time to get the bottles to fill and empty, while with cans it is super quick. My hands spend a lot less time in the acid and are much happier with the cans, and packaging takes less time.
2. While filling, I feel like I have better visibility into the can and waste less through overflowing.
3. The cans are SO MUCH LIGHTER. I have to haul everything up and down from the basement, and I definitely notice the weight difference.
4. The cans chill down much faster. I tend to not be very organized and sometimes forget to refill the beer fridge before going to bed. With cans, a couple hours in the fridge creates noticeably colder beer than the bottles I load at the same time.
5. I don't stress at all about handing some beers to a buddy; with bottles, I never got them back (or if I did, they came back with caked on crud in the bottom - maybe I need better friends?). With the cans, they are single-use and just go into the recycling.
6. Along the same lines, I don't have to deal with rinsing the empties and carrying them back down to the basement.
7. Of the cans I have opened so far, I have had ZERO duds (i.e., beers with no carbonation). Maybe it is just me and my crappy capping skills, but it seems like my bottles ended up with a dud at least every case or two. This always made me a little nervous giving away bottles, because I was worried about giving my bud a dud.
8. With cans, you can tell how the carbonation is coming along. When they are first filled, they are "squishy" - they firm up as they carbonate. This means you can just give it a squeeze to tell if it is ready. No more drinking an under-carbonated test beer!
9. I think that canning takes me slightly less time than bottling. For me, the biggest difference is the sanitizing time (mentioned above). Seaming might take a couple seconds longer than capping, but the difference seems negligible.
10. The cans stack really nicely, and it seems like they take less space than cases of long neck bottles. I use the plastic 4-pack holders and I stack 5-deep with no worries about something falling over.
11. I can take my home brews anywhere, without worrying about the possibility of having one break and leave sharp glass shards behind. If you drop and break a can, you just shotgun it! No broken glass and no wasted beer!
12. With bottles, I would use a sharpie on the cap to mark the style. Given the limited space, I would have very cryptic one or two-letter markings that nobody else could figure out. With cans, I use a sharpie on the side of the can, so I can actually write something that is useful to other people without needing a decoder ring.
13. The 4-pack holder make it easy to carry around a small number of beers. With 22oz bottles, I can carry a couple or a whole case in a carton. Makes it much more convenient to hand off a few beers to a friend.

The only negative to canning is long-term cost. The cans are somewhat less expensive than bottles, but they are single-use and you will end up buying lots more cans than bottles in the long run.

Answer 2

Well I am not so sure. They could explode if you aren’t careful. Sometimes just dropping a commercially canned beer or soda causes a rocket, so at least the cans that the commercial world use are about as lightweight as one can go under very controlled circumstances. I am not sure you have the ability to maintain that tight level of control in the home setup.

Answer 3

The risks are about the same as with any bottle or other container: over carbonation.

The key is measuring the amount of sugar accurately to not over carbonate and risk explosion. You have to make sure the beer as fermented completely as well, before conditionning, to avoid excess CO2.

Head space is also crucial, since cans do not have the same shape as bottles, you have to calculate it accordingly. Not enough head space can lead to over carbonation and too much space will lead your beer under carbonated.