Aeration of Wort

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Permalink Reply by oliver on May 29, 2013 at 2:57pm

Tip: don't get the cheapest air pump off trademe like I did as it doesn't have the grunt to push the air through a diff stone :p No idea how to tell whether a pump is going to be grunty enough though sorry.

The one I bought is Aqua One Infinity AP150R Aquarium Pump
They actually have a physical shop so maybe you could go there with a diffusion stone and ask to try some pumps? 

They're at 397 Ilam Rd.

I've had some luck using the pump without the diff stone, can only run it for so long in the carboy though until foaming becomes an issue...
Pure O2 is ideal obviously but really pricey to get a tank I think.

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Permalink Reply by Crusader-Rob on May 29, 2013 at 3:55pm

Yeah Pricing on those Oxygen tanks is huge. Its a shame really, because Oxygen is by farthe best way to do it. and not only is it easy to do its quick as well. the aquarium pump take about 30mins on and off based on what I've read?

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Permalink Reply by Damon Colbert on May 30, 2013 at 11:21am

Depending on the source, there are some who suggest pumping air is as/less effective at dissolving oxygen than just swirling your fermentor around.  Hard to tell how carefully they ran that experiment though (http://www.wyeastlab.com/hb_oxygenation.cfm)

That said, I've read suggestions that over-oxygenating wort could lead to excessive cell replication, and consequently production of off-flavours prior to fermentation.  It's said that pitching the required amount of cells to ferment the batch from the outset is better, or at least only use an air pump.  (e.g. http://tinyurl.com/pdc3j3l)

I would have thought an aquarium pump would work; they should be able to pump through an aquarium diffusion stone after all.  Just make sure you get a filter to put in-line, so you don't pump dust through.

I've been looking at this disposable oxygen cylinder (http://tinyurl.com/oh2qfvd) and regulator (http://tinyurl.com/persxs6).  Not cheap, but not prohibitively expensive.  Thinking of making a trip out there sometime fairly soon.

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Permalink Reply by Damon Colbert on May 30, 2013 at 11:45am

Then again, Jamil adds (in that same thread);

"If you're not going to add O2 to the wort, you're going to need to pitch more yeast than if you do add O2. For me, I tried a number of batches of lagers (Ofest) with no O2 and more yeast to limit growth in the beer. A lot of people told me it wouldn't work, but the resulting beer was quite clean. Very clean. Too clean. The beer ended up seeming a little dull overall. I switched back to targeting some yeast growth in the beer. As the folks from Wyeast and White Labs will tell you, you must have some yeast growth or the beer just doesn't taste right."

(bottom of page 4)

Don't mind me. Just having a one-man debate here.

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Permalink Reply by oliver on May 30, 2013 at 11:54am

Yeh, was about to reply with a similar comment - i.e. the recommended pitching rate (e.g. mr malty) is probably not always the same as the pitching rate you would need for zero growth.
Obviously you don't want to under-pitch or over-oxygenate either.

Neva from whitelabs talks a bit about aeration here too: http://www.youtube.com/watch?v=2vELwUsBmWQ

Aeration is well worth thinking about if you're re-pitching yeast too.

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Permalink Reply by Chris Banks on May 30, 2013 at 11:54am

How bout dragging up this thread from back in the day about Olive Oil as a sub/.partial sub?

http://www.forum.realbeer.co.nz/forum/topics/1500433:Topic:8?commen...

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Permalink Reply by Crusader-Rob on May 30, 2013 at 12:48pm

Ha! all Good. Don't they say that talking to yourself is a Sign of Sanity.... Or is it the other way around :)

Yeah I'm trying to find a way to avoid Lifting an swirling etc of the wort, for 2 reasons.

1. streamline my process so to speak

and 2. so i dont have to do some much work/exercise. I'd rather not ruin my shoulder all over again. lol

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Permalink Reply by David R on May 30, 2013 at 3:07pm

"Depending on the source, there are some who suggest pumping air is as/less effective at dissolving oxygen than just swirling your fermentor around."

As someone with only a little brewing knowledge but 15+ years keeping aquariums I completely agree with that. Bubbles flowing through the water/wort may look pretty and create a bit of movement, but just think of the surface area of a bubble and the amount of time it has in contact with the water. There is a very small amount of oxygenation happening at the surface where the bubbles burst, but thats it. The best way to get oxygen into the water/wort is through surface disturbance. I would expect that the amount of time needed for a typical air pump and diffuser to make a worth-while increase in the oxygen levels of a fermenter of wort would make it impractical, especially when a vigorous shake will do a far better job in a fraction of the time.

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