Am I over-oxygenating my wort?

[OldGoatBrewing]

I used to use an aquarium pump to aerate my wort. Within the last couple of years I have started using the disposable oxygen bottles at the hardware store. They work great, but I am using a whole bottle on two batches of beer. At over $10/bottle, I can't afford to keep doing this. Am I just opening the nozzle too much, aerating for too long or are some of you experiencing the same. When I oxygenate, I open it enough to get a flow that approximates a rapid boil... And I do that for a minute. I get good fermentation results, but would I get the same results with much less oxygen? And since I'm thinking about it, why not just go back to the aquarium pump? Thoughts and criticism always welcome...

 

[MaxStout]

Those disposable tanks should be enough to oxygenate several batches. Are you passing the O2 through a stone into the wort? It shouldn't look like boiling; most of the O2 should be dissolving before making it to the surface. Lower flow rate + longer time is better than fast and furious.

 

[OldGoatBrewing]

MaxStout, that makes perfect sense. If it is bubbling, it is escaping the wort. Sometimes the simplest things escape me. Yes, I am using a 2-micron stone. I will slow things down some and see what happens. Thanks much for your quick (and common sense) reply.

 

[murphyslaw]

I use just enough flow that I'm sure it's coming out. Barely, if at all, breaking the surface, for about 90 sec

 

[OldGoatBrewing]

Thanks murphyslaw! That is what I will do from now on....

 

[Vale71]

Get a 0.5 micron stone. With a 2 micron stone most bubbles will still make it to the surface before being fully absorbed.

 

[kh54s10]

And as far as I know my chemistry, the wort will only absorb so much oxygen. So, you are not over-oxygenating, you are just wasting oxygen.

 

[Qhrumphf]

You can't over-aerate as the level of oxygen in air isn't high enough to over-oxygenate.

But if you use pure O2, you can indeed overoxygenate.

But if you're blasting O2 and it's all bubbling to the surface and not dissolving into solution in the first place, then yeah that's just wasting.

Milwaukee sells a relatively inexpensive DO meter that'll appropriately verify DO levels when oxygenating (10ppm is what I'd shoot for). It's nowhere near sensitive enough for trace DO for oxidation purposes though, so most folks probably wouldn't want to spend ~$100-150 (on Amazon now for $160 but I've seen cheaper before) just to verify they're oxyenating appropriately. But if you've got other reasons to measure DO that aren't brewing-related (aquarium maybe? i don't know) it's something to think about.

 

[soccerdad]

I never went to disposable o2 tanks - I am a landfill freak. I used an aquarium pump at 10 to 20 minutes for a while and then got an o2 regulator from Williams Brewing. Now I get an o2 tank from the same place I get co2. Have yet to refil it. I run it for 60 seconds per batch (5G batch).

 

[Qhrumphf]

One other thing to keep in mind, some of your foaming properties are one-and-done (don't recall the exact mechanism offhand). The more foaming you create early on (blasting air for long periods of time, shaking the snot out of it, blasting excessive O2) the worse head formation and retention will be down the line.

 

[Tom R]

I spent $13 on an oxygen flow meter. and put it inline right after the regulator.

https://www.amazon.com/JIAWANSHUN-0...coding=UTF8&psc=1&refRID=D42ARXYBRC096EWQW35F

For a 5 gal latch I run 90 seconds @ 1 liter/minute using a .5 micron stone. Should result in 12ppm.

 

[kevink]

I spent $13 on an oxygen flow meter. and put it inline right after the regulator.

https://www.amazon.com/JIAWANSHUN-0...coding=UTF8&psc=1&refRID=D42ARXYBRC096EWQW35F

For a 5 gal latch I run 90 seconds @ 1 liter/minute using a .5 micron stone. Should result in 12ppm.

I use a very similar flow meter. It's awesome to know exactly how much O2 you pump into your wort so you can be repeatable from batch to batch.

 

[cswant88]

I use the red Home Depot oxygen bottles with a 2 micron stone. You should adjust the flow until you only see a few bubbles breaking the surface, that’s what I do. In my experience, the 0.5 micron stone clogs way too easily. I usually hit it for 60 seconds on low-moderate gravity wort, and 2 minutes on higher gravity. One of these days I’ll get one of those medical oxygen bottles with a nice regulator and flow gauge.

Edit: I’ve oxygenated half a dozen brews on my current little red bottle and it’s still going.