Bernzomatic Oxygen and Off Flavors

[roger456]

You didn't mention what the "off flavor" tastes like...

[triplepoint]

Thanks for all the feedback. I'll definitely sanitize and boil the airstone before i use it again, I suppose it can't hurt.

I'm tempted to believe the flavor isn't an infection, though, because it isn't getting worse the longer it sits in the keg. I guess that's not a sure-thing, but still it suggests it's some sort of non-biological contaminant.

As for what the flavor is: it's hard to describe. At first I thought it was too much bittering hops, because it was sort of a strong bitter flavor, not so apparent up front but lingering badly after the finish. But the more I compare it to other beers, the more I'm thinking its not quite a hop flavor.

My second guess was tannin extraction from the steeping grains (it's jamil's american amber ale, about 1.75 lbs of steeping grains in it). But i've scrutinized my steeping process, and I'm almost convinced that's all ok, too. I keep the temperature between 155 and 160 during the 30 minute steep. I keep the water volume low during the steep to encourage a lower pH. I'm using carbon filtered water, and city water here is pretty good to begin with. I've tested my water pH with beer-range strips (4 to 6) and it was off the chart basic, but that could be 7. I'll need to get some larger-range strips and test it again. At any rate, I'm not sure its an astringent tannin flavor either, I've had other people (including my club's BJCP judge) say that they know that flavor well and this isn't it.

So really I'm sort of stuck. I chased down the aluminum-flavor theory by going to a keg-kettle, and that wasn't it. The only other thing I've changed in recent beers is the oxygenation system, and looking at the record - 100% of the beers I've oxygenated with the bernzomatic tank have this flavor very strongly and 100% of the ones that weren't oxygenated do not have this flavor (admittedly, we're talking about 2 beers and 1 beer here, not a very large sample).

I'm going to try the same recipe again, but without the O2 and see if that makes an obvious change. Thanks again for the feedback,
- TP

[Lars]

Hmmmm maybe over oxygenation? Post your oxygenation routine and maybe there is something in your routine that can be adjusted.

[codewritinfool]

I've had what I think is the same flavor in two AG batches, kind of like a roasty burn on the tailoff. At first I thought it was tannin extraction, but later convinced myself that my city water absolutely sucks. Oh, and I didn't oxygenate those two.

I still don't know if I fixed it or not, because my latest beer has some kind of infection. Petedadink thinks it might be Acetobacter. I think I agree.

You know, you probably don't want to take any brewing advice from me.

[triplepoint]

As far as my oxygenation process goes:

I bought one of these:
http://pivo.northernbrewer.com/nbstore/ ... on&x=0&y=0

and one of the above-mentioned bernzomatic tanks.

After siphoning from my kettle to my carboy, and after the wort has reached pitching temperature (68F in both cases), I sanitize the airstone and hose, insert the hose into the carboy (trying to get it down to the bottom as much as possible), attach the bottle, and crack the regulator wide open for 60 seconds.

The first beer may've been 45 seconds, I'd have to check my notes.

After that, I remove the hose, pour in the starter's worth of yeast, attach the blow-off hose and off it goes. Then I clean up the hose and stone with hot water and oxyclean.

The only soft spot in this process is the duration over which to oxygenate. I'm not sure how long that should go. Is 60 seconds too much?

I'm not really sure what over-oxygenation flavor would be like, but I just assumed it would be a yeast flavor of some sort, and this doesn't seem yeast derived. But I could easily be wrong.
- TP

[triplepoint]

A a bit of an update:

I took a glass of carbon-filtered tap water just now, and used my oxygenation rig to bubble O2 through it for 60 seconds.

There was no visible iridescence on the surface of the water, so I don't think its oil contamination. more importantly, the off flavor was not present.

So If the cause of my troubles is indeed the oxygen, then it must be reacting with something in my wort, because the bernzomatic tank itself is evidently not causing it. Hmmm. I guess I'll know more when I brew my next beer.
- TP

[SacoDeToro]

I've been using the Bernzomatic O2 tanks for about 4 years without any issues. I have the O2 stone that's on the end of a long stainless wand. Williams Brewing often carries these. I do not have an inline HEPA filter, which I personally believe is overkill. I put my O2 wand in a StarSan bathc at the beginning of my brew day. That allows the StarSan more than enough time to penetrate everything. As a note, none of the professional brewers I know use a HEPA or pre-filter for their O2.

[Techie101]

I could be wrong but wouldn't pure O2 be sterile anyway? Can anything live in a pure O2 enviroment? I know humans couldn't.