Well, it’s bound to happen sometime, and today I have been hit with an infection. It sucks, but it gives me a chance to write about it. If you have been brewing for any length of time, there is a good chance you either have been hit with an infection, or you will sometime. For me, it has been a few years since I have been infected with something. I have, what I think to be, very good cleaning and sanitation practices. I clean my equipment, I replace hoses and plastic parts often, and I give the equipment and bottles more than enough contact time with Star San. Still, something is bound to be in the air or hiding somewhere along the line. But the trick is that once this happens, you need to put on your detective hat and figure out what may have gone wrong so you can avoid it again in the past. That is what I am going to talk about today. So here is my situation……

My infected beer

As you can see I have what are called gushers. What exactly causes the gushing is not known at this time, but it is thought that whatever the infecting agent is, forms some sort of protein that allows for nucleation points and gives the CO2 a place to form and gush out of the beer. Sort of like dropping Mentos into a Diet Coke. This gushing happens when you pop the top of the bottles, the beer foams out and sometimes comes out in a stream. It acts a lot like a shaken up beer, but you did not shake it. Normally it will also continue to foam out of the bottle for some time. There can be a few causes of gushing, one is from a fungal infection in the grain called Fusarium. Fusarium is killed during the malting process, and if it were to survive there it would surely be killed in the boil. The toxins produced from the fungus withstand the boiling process though. The use of Fusarium infected barley is a common cause of gushing. However, Fusarium infection is not the only cause of gushing. It can be a few factors and I don’t think Fusarium is the cause of my problem.

When this happens, it helps to think about something you may have done out of the ordinary during this batch. It also helps you narrow down a cause if every bottle is infected, or if it is just one or a few. If it is one or two, it was probably something with the bottle. The whole batch however, is a different story. Did you use a different fermentation vessel than you normally use? Did you not sanitize your bottle tree? Did you think you could get away with a shortcut you normally don’t take? Did you drop something into the beer on accident?  Basically, what was different?

In my case, everything I did was as I normally do. The auto-siphon I used was fairly new, it was clean, and well sanitized. The hoses were new, and sanitized. The aeration stone was boiled and the hoses were sanitized. I had a micron filter put in place between the pump and stone. I sanitized everything that came in contact with the cool beer. I did not mill any grains in the area, or around the time of brewing or bottling (raw grains naturally have bacteria on them, like lactobacillus). I checked my bottles and sanitized them with a long soak in Star San.

So what did I do? Well, the only thing I can figure out is that I used Coopers Carbonation drops. I used these before in a batch that I kegged and I bottled, so I had some left over. I thought they would be alright because I had them sealed in a bag. This is the one thing I can think of that I did differently. I don’t think the carbonation drops in the original package are sterile, so I figured it would be OK. However, when I think of it, they have been sitting for some time and could easily have harbored some sort of bacteria or wild yeast that was slowly consuming the sugar. There was some time for humidity to set in and make the outside of the sugar moist at one time. I am willing to bet that this gamble is where I went wrong. I used those drops in every bottle in the batch, and the beer was infected in every bottle. It makes sense that this infection took place after bottling because during bottling the beer tasted excellent. Also, right after carbonation it tasted quite good. It was not until 2 or 3 weeks after they were carbonated that I thought the beer started to taste a bit off, with a funky overly bitter and sour taste.  Then a week or two later the beer seemed to really pop in the bottle, like it was over carbonated. Then not too long after that, we have this.

So I am willing to bet that whatever took hold, did so during bottling and the carbonation drops seem to be the perfect villain in this story. So if you ever use these to bottle a few bottles, as well as keg. Don’t use the leftovers. You would probably be better off figuring out the dosage for the amount of bottles you want to use, and boil corn sugar and add that to the beer instead of using a few carb drops.

Finally, you may be wondering what I do now that I have an infection. Well, this part can get a little pricey, but I feel it’s the most effective way to ensure your next batch is not infected. That is to replace all the parts you can. Although I don’t suspect my autosiphon, it may very well be the cause and I just don’t know it. So at this point it is better to replace all plastic parts and hoses. So I am replacing my autosiphon, my hoses, and micron filter. My aeration stone is getting an extended boil to kill anything that may be inside there. Bottles are easy. I am just cleaning them and sanitizing them now. Then when my next batch is done, those bottles will be sanitized again. Carboys should be cleaned and sanitized and plastic buckets replaced. This may not be feasible for everyone because of budgets, but do the best you can. At the very least replace the autosiphon and hoses. Right now I am sanitizing my bottles are I write this.

Now grated there could have been many other causes. It could have been something in the air that day when I bottled, I could have had some solid particulate in a hose or some little nook somewhere, there may be a small crack harboring some bacteria. But because of my practices and how I check my equipment over, I just think those are less likely causes. The only real way to be sure that it was the left over carbonation drops, would be to replicate the mistake. But when it comes to infected batches, that is one process I don’t want to replicate. Now if I brew again and this same batch develops something, that will take a bit more digging.

If you think there may be something wrong with one of your beers. You can get some hints on what those may be. Sometimes flaws are not caused by infections of bacteria or wild yeast, but could be something that went wrong in the brewing process. Feel free to check out the beer evaluation page to get some links and documents on troubleshooting your beer.