Help Troubleshoot Infection

I've brewed 11 beers so far. All beers are extract + grains, partial-boils. My 2nd beer (kit pale) had an off-flavor that I never could really describe. Girlfriend said cardboard, her father said banana, I never really thought those fit, more like flat wet dog. It was drinkable but not good. All other beers after that have been fine (some great, some ok, but nothing bad like this).

Now, batch 10 has the same flavor. Its a different pale recipe (Haus Pale), done in a different kitchen/apartment, but the flavor was instantly recognizable. Girlfriend's father said banana again, but I took it to the LHBS and he identified it as bacterial infection. In fact, it foamed up enough for him to diagnose it 1 second after popping it. Then smelled and tasted it to confirm. He said sour, but I don't really taste it as sour either. It foamed up quite a bit, but not like regular over carbonation. I've never seen/noticed that before from the other infected batch. I did notice a slight oil slick on this beer when I bottled it, but I don't remember tasting/recognizing this off-flavor at bottling time. Online research suggested it could be from StarSan, or hop oils, etc. so I didn't think too much of it.

The store owner ran through my cleaning and sanitation procedure trying to help troubleshoot. He mentioned some things that I wasn't sure about, so hope some here can help me straighten things out. I'll try to outline my procedure in detail to avoid the inevitable follow-up questions.

Vinyl hose, auto-siphon, plastic racking cane, plastic spring-tip bottling wand
Plastic bottling bucket (only one, used for all batches)
Bottles, all from commercial-bought beer, mostly used once or twice for homebrew
Glass carboys

After using equipment I rinse everything out ASAP with hot water, and wipe down with sponge (might have some dishsoap residue, but not really soapy) and rinse with hot water.

Often, but not always, depending on how dirty, I soak my small/plastic equipment in OxyClean-Free for an hour or few, then rinse. I do this either before or after using, and feel I should be more consistent about doing this always.

I clean the carboy by soaking in OxyClean and rinsing until clean. I rarely use the Carboy Brush on it anymore, as the Oxy makes it clean.

Bottles are originally soaked in OxyClean to strip labels. Immediately after drinking homebrew I rinse them out a few times hot water/swirl/dump/repeat. If the bottom is clean, they go to dry, if there is gunk, a hot water soak until clean. I rarely need to use a bottle brush on them, as soaking fully cleans the residue.

Bottling bucket gets a quick wipe before use, then StarSan spray/fill, drain through the spigot. Equipment that is visibly clean then goes in a tray full of StarSan for a while to sanitize. I have a spray-bottle of StarSan on hand too, which I refresh every few times I brew (monthly, or so) and periodically check for pH <3.0 and clearness.

Things that LHBS suggested:
Don't use OxyClean. Use sodium percarbonate instead. Oxy is 'similar' to PBW but not good enough. Sodium percarbonate is 'similar' to both, but better than Oxy?

I must use a brush to clean the carboy and bottles to remove/prevent beerstone. I wasn't aware of beerstone, and had trouble confirming it formed on bottles and carboys?

Obviously, toss plastic equipment (tubing). Do I need to replace the auto-siphon, cane and bottling wand and bucket too? I'm looking into a SS racking cane, and a siphon alternative. Plastic sucks, and I want to regularly replace as little equipment to avoid worry and risk.

I understand the casual rinse of drank bottles, and mere soak of the carboy are minimal, but I understood them to be fairly common practice without much issue. If you don't see stuck muck, don't worry about it?

I've tried to cover my major process, but I'm sure I've left something out, so please help me pinpoint my likely mistakes, and interpret the advice I've gotten.

Thanks
Aaron

why are you using a sponge? sponge is a prefect place for bacteria to get trapped and grow. i just use brushes.

other than that, everything else sounds like good ideas and good technique.

if you have an infection then you will probably see a tiny ring of gunk in the neck of the bottles where the top of the beer level is. do you see that?

I use a sponge to clean out my plastic fermenter, too, to avoid scratching it. However, I also sanitize all my equipment again and let it dry before putting it away after brewing.

I use a sponge to wipe things that have just come out of the beer and have stuff stuck on them: spoon, outside of auto-siphon/cane, wine thief, IC, bottling bucket. This is just after using them, and then eventually get rinsed w/ hot, dried and maybe soaked in Oxy before use. Or, just dried, then wiped with a clean, damp rag for dust, then sanitized and used. I use the sponge mostly on plastic things, as I know brushes and scrubby pads can scratch plastic.

I don't see any residue or gunk in the bottles at the moment. When we opened one yesterday, after pouring, the foam that came up was large soap-like bubbles (like starsan foam), not like lots of tiny carb-bubbles. I had never seen/noticed that before. I did open and pour a few 3 weeks ago, which didn't seem abnormal, except for the taste. I know it will get worse over time, so makes sense to see it now.

EDIT: Do lots of people sanitize again after cleaning, and before storing?

i have never had a problem with infection and i don't usually sanitize after cleaning.

it takes water and some time for an infection to grow, so as long as you clean and hang the equipment upside down to dry in a clean area (not in a moldy basement) then it should be clean and ready to store until you sanitize and use again.

Heh. I just figure I still have the sanitizer out, might as well hit everything again. I'm probably not the norm there.

Just to add: I forgot to mention, at the LHBS the bottle was unchilled. Not sure if it would make it appear infected?

Today I chilled one, and tried it. It didn't foam at all, is well-carbed, tasted kind of sweet and floral (wet hoppy), but doesn't have the off-flavor! I've had a few other beers tonight already, so I'll need to taste a few more to form a better opinion. Maybe some bottles are infected but not others?

I guess I'm going to replace my vinyl tubing, keep the autosiphon, and brew another batch with slightly 'enhanced' cleaning and sanitation procedures: Oxy soak, rinse, visual inspection, sanitize.

Thanks

I think the general rule of thumb is to replace everything that's not glass or metal.

I am a Starsan freak. I have an old bottling bucket I soak everything in until Starsan until I need it. Great thing about Starsan is there's no rinsing involved (don't be afraid of the bubbles) just in the very very small chance you have a contaminated water supply.

Bleach is my savior

I had a few mystery infections when I first started brewing. I was cooling my wort by putting my kettle in an ice bath in the sink and then pouring it into my fermentor. I believe that I introduced an infection by allowing contaminated sink water drip down the outside of the kettle into the fermentor. If you cool this way, make sure you thoroughly wipe off the kettle before pouring.

Do you sanitize your bottles? If you're just rinsing them, that could cause problems.