Dissolved oxygen in finished beer

I took two samples of finished beer down to a friend who can test for dissolved oxygen.
This was a 5 gallon batch of American Pilsner that I bottled after lagering for 3 weeks in a secondary vessel.
I purged with CO2 wherever possible and racked into a bottling bucket where I added 4.4 ounces of priming sugar and stirred with a stainless steel spoon trying not to splash while still getting my priming solution well mixed.
I took a sample prior to filling the first bottle and another three or four bottles from the end using my racking cane again with a bottle filling wand.
The first sample tested .06 ppm and the second .05ppm.
The only published information I have seen regarding this other than any dissolved oxygen is bad is that .05 is the maximum acceptable level generally allowed.
I was curious how my processes were performing and thought I would pass along the information.
Any ideas how I may lower the levels further would be greatly appreciated.

Vacuum chamber.

So... does it taste bad?

The yeast should consume any oxygen in bottle-conditioned beer.

The headspace in the bottle might contain 02. I've read the bottle filler can cause 02, but I don't understand that. Another idea would be using a blichman beer gun to bottle.

I'd be interested in hearing about any further testing you do.

GilaMinumBeer said:

Vacuum chamber.

Click to expand...

That idea sucks.

I have never had trouble with oxidation and all of my beers to date have aged pretty well. I would guess that my process is pretty clean.
I do think it is an area in the process that for home brewers could get sloppy and effect the finished product and shorten shelf life.
I would be hesitant to try but curious to know how the results would be affected by not purging everything with CO2.

When you say racked, do you mean with a bottling wand, right?

What is the meter mfg and model #? Some meters have as much as .2mg/l of error between 0-20mg/l. (Like the ysi pro20)

Or did he do a Winkler titration?

Basically I wouldn't worry about it if it tastes good.

I haven't had any of problems only curious because I have access to the equipment.
The tech down at the waist water treatment facility lets me bring samples in for testing.
When I started oxygenating wort I brought samples in and was able to dial in my processes for that.
The finished beer tests were with me taking every precaution to avoid introducing oxygen into my finished beer.
I may take a carbonated, bottle conditioned beer in for testing to see if the O2 is driven out by the carbonation, conditioning process.

I'm sure he has a decent meter but I would look at the manual to check the accuracy. With a reading of .05 or .06 mg/l and a accuracy of +/- .2mg/l it would be hard for me to be concerned. If you are bottling I would think that any oxygen would get used up in the priming process. That all said this why I try to keep my beers out of the lab. I use it as way to break away from work. No use seeking out problems that don't exist. DO meters can be manipulated slightly by the user, this is not a criticism of your friend. Its just a fact of the meter and how quickly one stirs the probe. Again I trust your friends ability but i would be hesitant to worry about or trust such low readings with out knowing the thresholds of that particular meter.

I suppose if I worked in a lab maybe I would be singing a different tune but I am looking for every opportunity and advantage to hit my marks.
If I spend $30.00 - $40.00 and 12-14 hours to brew 5 gallons of beer, I am going use every tool in my arsenal.
I have a TDS meter, PH meter, hydrometer, 5 thermometers, 2 fermentation chambers, a stir plate, a microscope, O2, CO2 and apparently OCD.
If something doesn't turn out the way I want it I will likely know what it is and can quickly remedy future batches rather than starting the guessing game.
Some things I do out of curiosity or as a gauge of how my processes are performing. Not necessarily because I think something is wrong.

To each there own, I'm not criticizing you either. I appauld your desire for process control. I have much of the same equipment minus the TDS and pH meter. As long as you feel its helping then who am I to say otherwise.

I just wanted to point out some practical things regarding DO meters and try to help put it into perspective. Knowing the limitations of equipment will help do that very thing. I work with waste water too but not as an operator. I don't think I said anything that youbuddy would argue with. That is unless they have an amazingly expensive meter, which they could. Though I would still like to see the mfg and model # as the readings you quoted fall well with in the +/-.2mg/l many have.

The TDS meter I use to check someone else's processes. The store I buy my brewing water from claims R/O among other purifying techniques so I check it to make sure it's close to stripped of solids.
The PH meter I use to check water ph prior to adding salts, mash, kettle pre boil, post boil, post fermentation, check my StarSan to make sure it's acidic enough to kill the nasties and ph for my starters.
I post information I get that I assume many Brewers don't have access to for informational purposes only.
For instance the microscope. I lagered a Pilsner for 3 weeks at 40 degrees and pulled a sample prior to bottling to have a look under the microscope. Much to my surprise and others as well not a single yeast cell. Kind of hard to bottle carb beer without yeast. I would guess many Brewers even experienced ones would say there would be plenty of yeast in suspension for carbonation.
Even for this thread, I wasn't really looking for help but just throwing out my results for those who might like to know. My bottling process is pretty standard among home brewers if I had to guess. I was quite happy with the results of that test actually but thought I would ask if anyone had suggestions as to what might drive the O2 down even further in my process.
Large craft breweries use deaeration systems that deliver 5,000-80,000 liters per hour. Current industry standards for acceptable oxygen levels in packaged beer is 50ppb, are typically 30ppb and the goal is 10ppb so it's importance shouldn't be overlooked and likely ultimately impacts shelf life.
For beers consumed rather quickly this probably isn't much of a concern.

Thats all fine. I know what those things are used for. In any case those numbers still me very little depending on the meter. That's all I'm saying how do you know its not 0.26 or 0.18 mg/l??? You don't. At least not with out knowing the specifics of the meter. I asked about the meter info to look up the manual to see if I could have confidence in what I was reading. I'm not trolling or looking to be schooledschooled. I'm genuinely curious but quickly losing interest.

If you measure in ppb you have to be careful with the sample. I think breweries inject a needle probe right through the beer can to sample. Even then I wonder if the needle would carry some 02 through into the beer.

My friend while out of work with the flu stated their machine has a resolution of +\- .02 mg/l.
He didn't know the name of the unit but mentioned it was a $4,500.00 machine and due to the nature of their work it had to be quite accurate.
I will try to get the make and model when it is convenient.

Well i'm sure thats a good meter and probably has a decent amount of accuracy. Though I would be remiss not to mention that the resolution is different than the accuracy. Using the YSI pro 20 as an example the resolution is selectable between 0.1 and 0.01 mg/l. No matter which you select, it still has an accuracy of +/- 20% or 0.2 mg/l which ever is greater.

I hope buddy gets better soon. The flu sucks.