Dissolved O2 in Wort

To measure you need a DO meter, and those are not cheap.

I use the volume flow rate with my O2 regulator and go from there.

 

It is EXPENSIVE and impractical for homebrewers to measure O2 saturation of wort.

There are several in-line devices available to take these readings, but they are expensive and only used in commerical breweries that I am aware.

Here is a link to a relatively inexpensive one (@ $1,500.00- it's relatively inexpensive compared to other 02 sensing units)

http://www.hach.com/product.detail-overview.jsa?id=7640513820

For all intents and purposes, it is not something that homebrewers can do affordably.

I can tell you that in-line oxygenation systems will have a higher efficiency than a wand or tube inserted into the wort/fermenter. But rate/flow/saturation is not something that is easily measureable. Too many variables.

I am unaware of any equation that would be accurate in measuring 02 saturation.

If someone knows an inexpensive and practical way to do so I WOULD LOVE TO HEAR ABOUT IT!

 

You have very weak Google-Fu. You can get O2 meters for under $700 from a scientific equipment company. There are methods to measure without a meter (See below).

You can do it at home without a meter via a Winkler Test. You just need to have common sense and the required chemicals and be able to measure a volume accurately when titrating. The Hach company sells DO kits.

Here are links:

http://serc.carleton.edu/microbelife/research_methods/environ_sampling/oxygen.html
http://www.ecy.wa.gov/programs/wq/plants/management/joysmanual/4oxygen.html

 

Ward, looks like I have some reading to do. Thanks for those resources!

 

there are also DO sensors out there for ~150$, but they require a relatively accurate DAQ board, if pressed for it I can dig them out and find the manufacturer

 

I know at least one homebrewer with a dissolved oxygen meter. IIRC, it cost him a couple hundred bucks.

 

Hopefully there's nothing in the wort that will affect the winkler test. I figure since its used for waste water, it should be fine, but when I give it a shot I'm going to definitely use a boiled and cooled sample for reference. Once my thesis is defended next week, I'll give this a shot alongside the DO meter we have in the lab.

 

arfdiggs, post: 1974485, member: 583505"]You have very weak Google-Fu. You can get O2 meters for under $700 from a scientific equipment company. There are methods to measure without a meter (See below).







You can do it at home without a meter via a Winkler Test. You just need to have common sense and the required chemicals and be able to measure a volume accurately when titrating. The Hach company sells DO kits.

Here are links:

http://serc.carleton.edu/microbelife/research_methods/environ_sampling/oxygen.html
http://www.ecy.wa.gov/programs/wq/plants/management/joysmanual/4oxygen.html[/quote]
Admitedly I am not an internet guy. This and my bank account and amazon are the only online stuff I really do.

Thanks for the info.

If they can be had for a few hundred bucks I'm gonna get one. Very cool.

 

Is such accurate reading of O2 levels really* necessary, or just a scientific curiosity?

If you're not using pure O2, there's a saturation limit (barfdiggs might know it offhand, I'm too lazy to look it up because it doesn't affect me much). I've worked in various labs (hospital, R&D, the latter doing mostly "chemistry," which translates into "mostly measuring a bunch of absorbances and putting them into spreadsheets and analyzing data"), and I can't think of anything from those labs that I'd really want to mix with my brew day, because then my brew day would come dangerously close to resembling my work day...

*well, I doubt it, because lots of us make great beer all the time, never thinking much about O2, except to "oxygenate" before pitching yeast, which frequently means "stir vigorously"

 

In Yeast there are practical guidelines to answer this question. They cite ppm from a 0.5 micron stone in a 5 gallon batch. I am not home but if someone who has access to a copy would look on page 79 and post the criteria it should help. Hmmm, can't find my car keys but remember the page number for dissolved O2 in wort ? ? ?

 

8ppm

 

With something like this I would use all the O2 I could find!

Also in Yeast is the suggestion to hit the wort with another dose of O2 when 12-18 hours into fermentation. This is after first cell division and keeps the new yeasties from gasping . . .forgot the page for this tidbit.

 

Personally, I wouldn't think the amount of improvement to one's homebrew would validate the $500+ spent on an instrument to measure DO.

 

From reading about it briefly, the Winkler test is gonna be a bitch if you have a dark wort, since you need to see the starch-iodine complex go away to know when you hit the end-point.

 

What you can do to get around that is to generate a calibration/standard curve with a light beer that tells you for x amount of time of O2 exposure at a fixed rate, you get y amount of oxygen. Its makes it so you really only have to do a couple runs of the winkler test and won't have to do it every brew day. We do this a lot in the lab.