A Few Contaminated Batches

Although most of my beers have been coming out 'clean', I've had a couple of my beers show up with what I think might be bretanomyaces or some other 'bug'. The contamination shows-up after they're bottled and have sit at room temperature for a while. It has that slight "cherry pie" flavor that shouldn't be there.

Oxi-Clean and Star-San

My standard cleaning process includes overnight soak of the auto siphon and plastic carboy with Oxi-Clean Free. I put about 1/2 cup of Oxi-Clean into the carboy with 5 gallons of hot (120F) city tap water and pump it through the auto siphon. The next day all visible material adhering to the carboy walls is gone. I triple rinse with city tap water. I then put a few cups of properly mixed Star-San solution into the carboy, pump it through the auto siphon, swirl to hit all interior surfaces, dump the Star-San and store the equipment. Before using the carboy or auto siphon again, I repeat the Star-San step. I don't think the contamination is from my counterflow chiller, but I'll mention that I store it full of Star-San, then during the boil, I run boiling wort through it without the chilling water turned on. So it sits at well over 150F for 10 minutes before I start the chilling process.

Salvaging Equipment

Apparently my sanitation practices are not good enough. I presume the problem is in the carboy and racking (I don't ever secondary, just bottle). So the question is, what should I do to "bring out the big guns" from a cleaning perspective. An easy step 1 is to throw out all my vinyl hoses. Consider that done!. But what to do about my auto siphon, which I'd hate to throw out. And also my plastic carboys. I don't see any scratching on them, and I've kept from using brushes on them, ever.

Bringing Out the Big Guns for Cleaning/Sanitizing

What more powerful cleaning solutions are available to me? Bleach? Boiling water? I saw something in another post about quat or something like that? I have not used PBW, and understand it's different than Oxi-Clean, but is that going to make the difference? I don't want to get into a religious rant about sanitizers, but is Star-San letting me down? I've never used Iodaphor, and don't know much about it. Should I use a powerful "yes-rinse" sanitizer first, and a no-rinse sanitizer after? If you have suggestions, please recommend specific concentrations.

  • Can you be sure it's contamination? If possible, get a brewer buddy to also taste and see. Your sanitization routine sounds thorough.
    – mdma
    Aug 27, 2012 at 7:36
  • I'm going to bring it to an event and get some BJCP guys to have a taste, but I'm pretty darn sure something is going on; The first 6L keg of 3 I drank right away and it was lovely. These next two... not so much. The one that was stored room temp the longest is the worst.
    – Dale
    Aug 29, 2012 at 2:00
  • 1
    How are you cleaning and sanitizing your bottles and caps? Are you using priming sugar? CarbTabs?
    – jessecurry
    Sep 2, 2012 at 15:29
  • 6 Liter bottles get an overnight oxyclean soak, quadruple hot tap water rinse, and an interior coating of starsan before storage. Before use, they get starsanned again. Caps get similar treatment. I boil corn sugar and water, cool for as long as my patience allows, split it into the 3 bottles (sanitized funnel) and rack on top of it.
    – Dale
    Sep 19, 2012 at 23:23

3 Answers 3


Although you could use bleach as a effective "yes-rinse" sanitizer, the chances are the bugs are in your environment, not just the equipment, so you'd have to do this before each brew, which is a bit of a pain.

Last year I had some slight contamination issues, which I later tracked down to my forgetting the correct dosage of Star San. (That's what happens when you take a 2 year brew-break!) But to be sure, I also alternate with iodophor, since I had some on hand. No contamination in the last 4 batches.

You mix 15ml/0.5 fl.oz. iodophor in 5 gallons. Contact time is just a minute, although I usually leave for a little longer. Iodophor is less effective on unclean surfaces, but since you've thoroughly cleaned everything, there's no problem there. Finally, the iodine does stain - I can't really see a change after a few uses, but I know that it will show eventually.

  • I'm ready to try anything to avoid this. It's discouraging to hear that I can get brett just out of the environment, which means there's no hope...need to find a new hobby.
    – Dale
    Aug 29, 2012 at 2:06

Clean, sanitize, keep it simple. Infections will happen because of other things in your environment. You could try wiping down all surfaces around which you will be working for a while. That may help. Also you could try replacing equipment which is inexpensive and more likely to be trouble, like stoppers and airlocks.

However, usually your key issue is that this sort of thing will happen from time to time. Usually it can be prevented between batches but you have to be aware that occasionally you have to do more. this isn't quite the same thing but I did run into trouble once with something growing in several successive batches of sauerkraut probably introduced in one of the seasonings in the first contaminated batch. Sometimes rotating equipment to another different fermentation use can be helpful (that's what solved this-- bucket going back to beer/mead and then back to sauerkraut).

  • Yep, I did switch from a racking cane to a autosiphon, and used a different fermentation vessel. I also started wearing rubber gloves when cleaning cold side stuff and during bottling. And I got rid of all cloth in my bottling process (towels). Not that I towel dried anything I'd sanitized, but I would move the towels around (dust) to dry the counter, etc. I think they might have been the problem. I keep a roll of paper towels, but I almost never use them... everything is drip-dry.
    – Dale
    Sep 19, 2012 at 23:17

You'll have to thoroughly examine your sanitation process. Of course we all think that we're doing it perfectly, but most of us are not. Think about any equipment that might not get sanitized (for example, your ball valve coming out of the kettle -- do you sanitize it before running the wort out of it? Look for things like this)

My hunch is that it's scratches in plastic that are causing you problems. I would suggest replacing plastic equipment. i.e. hoses, siphons, etc. Plastic is much more porous than one might think. Don't throw the old stuff out just yet, but don't use it until your contamination problem is gone. Then, you can re-introduce your (most expensive) old plastic equipment one piece at a time and make sure that your problems don't come back.

It shouldn't be any problem to clean and sanitize your metal equipment with an appropriate no-rinse sanitizer. What you've told us of your sanitation practices sound good, but you'll need to look at the entire cold-side process.

A story from personal experience: I don't think it had yet caused me contamination issues, but for the first year of brewing, I wasn't aware that you could take apart your three-piece ball valves. There is some nasty shit in there, where the ball sits. I now clean it each time I brew.

  • 1
    The ball valve on the bottom of the kettle sits at nearly 212F for an hour. Gook in there may be gross, but nothing is going to be alive in there!
    – Dale
    Sep 19, 2012 at 23:08
  • 1
    Of course you're right, Dale. I clean it now, regardless. :) It was perhaps a poor example, but the point of the story is that there is probably something you aren't thinking of in your sanitation/cleaning regime, if you're getting contaminations (and even if you're not). Sep 21, 2012 at 0:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.