Help with Troubleshooting Infections

[doctorseth]

Hello everybody,

This is my first post on here and I was hoping for some help and ideas with troubleshooting infections. I've been homebrewing for about a year with mixed success. I've made some beers that I'm pretty happy with but have had a perpetual problem of infected beers- not all of them but much too common (I'd say more than half of the beers that I've made below ~6% abv have been infected to some degree, though most are still drinkable). When I say infected, I mean that they are overcarbonated and have an off flavor that gets worse over time.

Anyway, I think that I am pretty knowledgeable on the overall process and I have an advanced degree in chemistry, even working with cell cultures at times in the lab. I say this not to brag, but just to point out that I have a decent idea of what I'm doing. I also try to be careful with my sanitation, especially at the most crucial times such as while cooling the wort. I brew in 1-gallon batches, make starters usually using White Labs yeast, use PBW and Star San, brew all grain using Brew in a Bag, and bottle my beers. For the bottles, I rinse them thoroughly after use and then clean them with PBW and Star San. Any infections that I get seem to be on a per batch basis so I don't think it's the bottles.

I think that the air in my apartment might be relatively dirty- I tried doing a spontaneous fermentation of some leftover wort and it was very quick and easy to get the wild yeast to take hold. The beer even came out tasty (and I may culture it to use for future batches) but I'd like to figure out what is going wrong or at least how to control it to a level that it doesn't significantly affect my beers. I have cleaned everything including the bottling area and I turn off any air flow in the apartment (AC or heat) during critical moments.

To make a long story short, I've done a lot of reading with no success and I'm hoping for any ideas that the community here might have for fixing/controlling this problem.

Sorry for all of the text- just hoping to provide any relevant information I can think of, and thanks in advance for any feedback!

 

[ImNoExpert]

I'd start by making sure you're mixing the starsan to the correct proportions.

I'd then move on to look at any of my plastic. Tubes, hoses, bottling wand, spigot on the bottling bucket, autosyphon or racking cane, etc. Any scratches or crannies where stuff can accumulate? The only time I had an infection was because I wasn't completely disassembling my bottling wand each time to make sure it got all cleaned out after use.

 

[daksin]

What is the "off flavor" you're tasting? Overcarbed beer is pretty not-tasty, IMO. Do you see a pellicle in the fermenter prior to bottling? Do you get mini-pellicles in the bottle? Apart from flavor, what tells you it's infected? You can almost always see badly contaminated beer- bad flavor and overcarbonation are different problems to diagnose. How do you prime?

 

[doctorseth]

Thanks for the replies!

I'd start by making sure you're mixing the starsan to the correct proportions.

I'd then move on to look at any of my plastic. Tubes, hoses, bottling wand, spigot on the bottling bucket, autosyphon or racking cane, etc. Any scratches or crannies where stuff can accumulate? The only time I had an infection was because I wasn't completely disassembling my bottling wand each time to make sure it got all cleaned out after use.

I am careful about my Star San proportions. Also, I checked the pH and it seems to be acidic enough (I was told that if the pH is less than ~3 it should be good). I've tried changing the tubing, etc. and also started disassembling my bottling wand but no luck so far. I may go back and once again replace some things but I don't think that is the problem.

What is the "off flavor" you're tasting? Overcarbed beer is pretty not-tasty, IMO. Do you see a pellicle in the fermenter prior to bottling? Do you get mini-pellicles in the bottle? Apart from flavor, what tells you it's infected? You can almost always see badly contaminated beer- bad flavor and overcarbonation are different problems to diagnose. How do you prime?

The off flavor is kind of a sour flavor that, along with the carbonation, will increase over time. I've had sour beers and I'm pretty sure that it's contaminated and not just overcarbonation.

Sometimes there is a small residue on the side of the bottle at the top of the liquid but not usually. Most of the beers taste fine coming out of the fermentor and I've never noticed any pellicles or anything like that. Do you think that the problem then is post fermentation? Or is it possible that it is present during fermentation and only becomes noticeable later?

I prime by dissolving table sugar in boiling water (calculated using an online calculator from Northern Brewer that takes into account temperature, volume, etc.), cooling it, and racking the beer onto that before bottling. My high gravity beers always come out fine on the carbonation, which I think is consistent with the issue being contamination. Do I need to be boiling the sugar solution for some amount of time or is it sufficient to boil the water and then add the sugar to it?

Once again, thank you for the ideas- it's helping me to think this through. The more I think about it, the more it does seem to something that is happening during the bottling process.

 

[derek8307]

This sounds very much like my issue. I'm very curious to know if you resolve it.

 

[Ozarks Mountain Brewery]

its most likely the fermentation temperature, the instructions on those kits are misleading, wort can raise as much as 7 degrees from the air temperature so if your fermenting at 70 your could really be fermenting at 77 for the first 3 days and that leads to off flavors from the yeast, try fermenting at 65

I personally ferment at 60 and since I started that years ago I have never had an off flavor

 

[doctorseth]

its most likely the fermentation temperature, the instructions on those kits are misleading, wort can raise as much as 7 degrees from the air temperature so if your fermenting at 70 your could really be fermenting at 77 for the first 3 days and that leads to off flavors from the yeast, try fermenting at 65

I personally ferment at 60 and since I started that years ago I have never had an off flavor

Would fermentation temperature control account for the sour flavor and overcarbonation? I do not have a converted fridge yet for temperature control but I have fermometers on the carboys and use a swamp cooler. I keep a pretty close eye on it and, while it does fluctuate, I keep it ~68 and it rarely goes higher than 70-72. Also, the flavors that I'm referring to aren't generally noticeable at the end of fermentation but show up later in the bottles.

 

[ImNoExpert]

Do you use a bottling bucket with spigot?

 

[doctorseth]

Do you use a bottling bucket with spigot?

No I use an extra glass carboy to transfer into and then bottle out of that using a siphon and bottle filler. I'm thinking maybe I should buy a new bottle filler and replace that as well.

 

[Ozarks Mountain Brewery]

a sour flavor usually means it got too warm before fermentation, just like milk souring and wort can sour too under the right conditions, you might have waited too long to pitch the yeast

 

[eluterio]

Im just trying to understand your process a little. Your brewing 1 gallon BIAG batches and making a starter from White Labs yeast vials. Im assuming your not using the entire WL Vial when making your starter. For 1 gallon batches there should be no reason to make a starters. I know this is now going off topic, how do you measure from one vial to get enough yeast to ferment 1 gallon.

Ok, so back on topic, you think your issue is coming from post fermentation. If the same taste is coming from different batches what type of beers are you making? It could be the over usage of darker malts. Making Stouts and over using darker malts can lead to having a sour taste. Buckets are cheap by a new bucket brew the same recipe that had the same sour taste. If the bucket was scratched and PBW was unable to clean it up well enough this could be your issue. To better use PBW try heating up the water to 150 and use that to clean out equipment. Ive noticed the heat with PBW kick ass when you let it sit and soak. I would stay away from using brushes or hard scratch pads to avoid scratches and would not store anything in the bucket as it could scratch the bucket.

Boil the sugar until it dissolves is usually best practice, 5 mins 10 tops.

If you able I would take your beers to a local home brew shop or club and have them taste it. They can give you some valuable feed back.