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Oxygenation of Wort


Otto Von Blotto

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I actually considered going down this route after reading a yeast book by White but decided to use the old aquarium pump method with no noticable results so I discontinued it. It maybe time to try out the oxy trick. I have a cylinder sitting in the back of my service ute permanently so It won't be much trouble rigging something up.

 

As for the safety aspect of oxygen it is quite safe and I've probably been using it on a weekly basis for longer than some people have been alive on this forum. Would you believe that I actually mix it with acetylene and then set fire to it and I'm still alive after all these years. It's called silver soldering. Oxy is quite safe just keep it away from oil especially in its compressed state.

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Yes well there won't be any oil or anything going near it. I'm looking forward to trying it out. It may have more effect on lagers than ales in the flavour department but if it speeds up the fermentation of both then I'll be happy.

 

Kelsey - I'm not sure if speeding up fermentation does the trick as too rapid of fermentation can throw off flavours as does too slow of fermentation. Too many cells can produce a too rapid fermentation, that is why I don't use yeast cakes as I would be dealing with an unknown number of cells. Likewise underpitching will result in too much yeast reproduction to consume the wort which can also throw off flavours. So from what I've read that is why there is an optimum number of cells for a given volume at a given specific gravity.

 

From memory in what I've read the introduction of oxygen greatly reduces the lag phase which will inhibit off flavours. I think this is what you meant by speeding up fermentation. In effect it does speed it up by giving it a kick start but the rate of fermentation should be similar to no oxygen being used. That's my understanding of it.

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It's my understanding that a normal ale fermentation shouldn't take any longer than 4-5 days to reach FG. Introducing oxygen does reduce the lag phase, but it also tends to give a healthier fermentation as well, which may cause it to ferment quicker too. There are a number of reports from blokes who have started using O2 like this whose fermentations have been reduced in time by 2-3 days and the beers improved noticeably as well, so I don't think the speed of fermentation on its own is responsible for off flavours if all other conditions are favourable such as temperature, pitching the right amount of yeast etc.

 

The usual reason for fast fermentations in homebrew is that the temp is way too high, because those using O2 wouldn't be in the majority. I would point the finger at the high temp as being the cause of off flavours more than the speed of the fermentation.

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That concurrs with what I've read regarding yeast health. Stressed yeast can throw off flavours regardless of how many of the little critters you've got in there. So by creating optimum conditions with oxygenation I guess you are giving yeast the best chance to produce a superior beer.

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I suspect that a lot of the homebrewers aerating with pure O2 are also removing dead cells from their re-pitches by washing/rinsing/pouring off. Such yeast will have high oxygen requirements as they cannot source the fatty acids and sterols they need from their environment and have to manufacture them. It seems to me these well meaning brewers might be first creating a problem that they then have to solve.

 

It would be interesting to do a side-by-side comparing high tech "clean" slurry pitches aerated with pure O2 to low tech "dirty" pitches of sloppy slurry aerated with room air by simple agitation. I am not convinced there would be an appreciable difference in taste.

 

That being said, I expect brewers who were pitching "clean" yeast and aerating with room air notice an improvement in lag time, and possibly flavour too, when they start aerating with pure oxygen.

 

Kelsey, I know you harvest from starters and not from slurry. I think you pour off the top, which is essentially beer; is that right? What do you do with the trub? Do you leave it behind when you pour off the yeast, or do you shake the yeast and trub together thoroughly?

 

Cheers!

 

Christina.

 

 

 

 

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Hi Christina,

Yes I pour the beer off the top of the yeast cake then just swirl the whole thing up in the flask and pitch it into the wort. It would be quite difficult trying to separate the trub from the yeast, and not something I can be bothered to do. I don't think there's much trub in the starters compared to the bottom of the FV after a full sized batch though.

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I don't see the point in cleaning trub full stop...

My personal preference is to use it unwashed...

 

Some of my nicest brews have been made from unwashed slurry that's been stored in a 500 ml jar in the fridge from 2 months

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Its the best way to go...

The yeast will love it

I can think of better ways to go.

 

I would rather die in my sleep than blow myself up tongue

Don't mind Hairy Waylon. He's just never been the same after that ill-fated clown balloon shaping disaster.

 

The sheer terror would have most lose all their hair via alopecia. Hairy went the other way. tonguewink

 

biggrin

 

Cheers' date='

 

Lusty.[/size']

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Its the best way to go...

The yeast will love it

I can think of better ways to go.

 

I would rather die in my sleep than blow myself up tongue

Don't mind Hairy Waylon. He's just never been the same after that ill-fated clown balloon shaping disaster.

 

The sheer terror would have most lose all their hair via alopecia. Hairy went the other way. tonguewink

 

biggrin

 

Cheers' date='

 

Lusty.[/size']

 

And now Hairy's hair is going grey. whistling

 

Cheers

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This little thing arrived in the mail today, it's a connection for the oxygen regulator to attach the line/hose to the Oxywand which obviously sits in the wort. Tomorrow I'm off to Craftbrewer to get the Oxywand among a bunch of other stuff so I will be able to give it a crack on my next batch which is being pitched on Monday.

 

post-25376-0-53855200-1478683663_thumb.jpg

 

Cheers

 

Kelsey

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Craftbrewer were out of stock of the Oxywands today sad apparently they've been pretty popular. Anyway, I've organised a temporary solution while I wait for them to get more in stock which is basically just a diffusion stone which I'll attach to the end of the gas line, and perhaps attach the gas line to my stainless mash paddle as well to keep it in the bottom of the FV, so I'll still be able to test this out on the next batch.

 

I have plenty of spare gas line from buying the wrong diameter unintentionally last year when I got my CO2 manifold for the kegerator but it will fit perfectly on the barb on the O2 regulator connection.

 

And if the wand has issues at some stage then I've always got a spare stone there. Can never have too much spare shit lying around, never know when you might need it! tongue

 

Cheers

 

Kelsey

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After Craftbrewer was out of the oxywands I lamented this fact over on the other forum and one of the guys kindly offered to get a diffusion stone for me from iBrew on the Gold Coast today while he was buying some other things for himself and have me come and pick it up after work tonight which I did. This is a temporary set up until the wands are back in stock, but I can now attach this thing to the end of the gas line in order to pump oxygen into the wort. Looking forward to trying this on Monday with my latest pilsner batch happy

 

15042115_10211552259910691_5488839353362763599_o.jpg

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Yes' date=' well with all due respect I think working on aircraft on a tarmac is a slightly different thing to injecting wort with oxygen for a minute or two in the laundry or wherever at home. I'd imagine there would be a lot more risk of contaminants causing problems there, or in other industrial situations where they are used.

 

The instructions that came with the regulator are pretty clear on how to make sure problems don't occur, as I'm sure they are with the BBQ gas bottles too. Problem is most people are morons and don't read them properly or at all and then end up injured or worse as a result. I'm not one of those people. [/quote']

Your probably right mate. Just paranoid after being told it was going to kill me for so many yearsbiggrin

Damn right that oxygen will kill you. Thats why i smoke. Keep that nasty oxygen away

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After Craftbrewer was out of the oxywands I lamented this fact over on the other forum and one of the guys kindly offered to get a diffusion stone for me from iBrew on the Gold Coast today while he was buying some other things for himself and have me come and pick it up after work tonight which I did. This is a temporary set up until the wands are back in stock' date=' but I can now attach this thing to the end of the gas line in order to pump oxygen into the wort. Looking forward to trying this on Monday with my latest pilsner batch [img']happy[/img]

 

15042115_10211552259910691_5488839353362763599_o.jpg

 

 

Got one of these thinking it would work with a regular air pump. Its only recently I realised it was for high pressure delivery. I wonder if an oxygen concentrator would be a better bet. Perhaps initial cost more but then your not paying for bottle hire and refills.

 

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The 2 micron stones are better with air pumps and such like, these 0.5 micron ones won't really work with those but they are really good with the cylinders.

 

I set up my temp fix for this thing yesterday with a bit of spare gas line I had lying around attached to the stone. I hit my pilsner batch with it for about a minute or so then pitched the yeast and it's currently in the fridge at 10C. So we'll see what happens.

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  • 2 weeks later...

As documented in other threads, I didn't notice much difference in fermentation performance from the oxygenation process on my Bohemian pilsner, however, I think things could have been done better with the oxygenation and improvements will be made on the next batch due in the FV next Friday (2/12).

 

The first improvement will be using a wand instead of having the stone on a flimsy piece of hosing since CB got them back in stock and I ordered one this morning. This will allow much easier movement of the stone around the wort for better coverage, although the science suggests it makes bugger all difference. In any case, a rigid tube will be easier to use than a floppy hose (I'll wait for the innuendo comments... tongue).

 

Other things I'll be doing are increasing the time I inject oxygen into the wort and not pumping the oxygen in too fast as it just ends up bubbling away out of the wort anyway; I'll decrease the pressure to just a gentle flow of bubbles that just break the surface, rather than it looking like boiling wort. It's pretty much impossible to over oxygenate it under these conditions of injecting O2 into wort at normal fermentation temps, so I'm not worried about that.

 

The wort itself is a standard APA wort I've been brewing for years, containing Maris Otter, Munich II and medium crystal, mashed at about 66C, which will be fermented with the same old US-05 yeast as pretty well all the ones before it were. OG is about 1.048. Flavour differences will be hard to judge because of water treatment to accentuate the hops, and a hopping schedule I've not used before being all Citra, but fermentation activity can be compared to previous batches quite easily, given the same wort and yeast. I'll be interested to see how it works with these improved methods.

 

Cheers

 

Kelsey

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...In any case' date=' a rigid tube will be easier to use than a floppy hose (I'll wait for the innuendo comments... [img']tongue[/img]).

Probably not a good idea to cut & paste comments from that OTHER forum you frequent Kelsey! whistling

 

biggrin

 

Good luck with the oxygenation next time around.

 

Cheers,

 

Lusty.

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  • 2 weeks later...

So, as per the FV thread I have pitched my Citra pale ale today. This time with the oxygen set up, I dialled back the pressure so that there was just a gentle flow of lots of small bubbles out of the stone into the wort, rather than it looking like it was boiling. I also ran it through the wort for about two minutes this time, which was made a lot easier with the wand. I was able to see the flow when I put the wand up against the side of the FV and it was much better, and easily move the stone around the whole of the bottom of the FV. Whether that makes a difference or not I have no idea but it was still better than a stone on the end of a hose.

 

I'll take an SG reading on Monday as I won't be here over the weekend, which is unfortunate from a monitoring lag time point of view, but the SG reading will obviously give an indication of how quickly it ferments. I suppose looking at krausen residue would give an idea of the size of the krausen too.

 

Looking forward to seeing how this goes happy

 

Cheers

 

Kelsey

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Hey Waylon, this batch is only the second one I've tried it on, the first batch was a pilsner which was kegged and bottled 2 days ago so no idea how that turned out really other than the FG samples which were very nice. I mucked up the process on that one though, so this one today is really the first one I've used it properly on. I'll definitely keep the thread updated though.

 

Crappy picture but this is the whole set up in action:

 

15350578_10211838832194819_1473041803965231705_n.jpg?oh=8661db1231b4909ae432bc1dfb033668&oe=58B15D2E

 

Cheers

 

Kelsey

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Nice one OVB, it will be very interesting to see two identical batches fermented side by side, one with Oxy and the other without for a true test, perhaps you could do a 40L batch and split it between two small fermenters?

 

Also, you can buy Dissolved Oxygen Sensors pretty cheap now, so you could easily find out how long it takes to completely saturate the wort with Oxygen, so you don't under or over oxygenate.

 

I would caution the use of pure Oxygen in a semi-confined space, like a laundry, though. I saw a test done once with a Hi-Vis shirt that had 40% (so double the atmosphere) Oxy sprayed on it for 5s and then a grinder used to shower it with sparks and it just erupted in flame. Even in small concentrations it can be incredibly hazardous. I also do work with liquid oxy valves and even a dust particle can cause an explosion so they are absurdly clean before being installed. Not the same thing, I know, but something to think about when mucking around with it.

 

Just make sure you have the doors open for airflow and be away from anything that can spark, mate. Maybe take the fermenters outside to do that part?

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Unfortunately I don't have the capacity to do a 40L batch, or the room to stick two full size fermenters in my ferment fridge either. I could do a 21L batch and use two smaller fermenters, although I don't have any small fermenters either lol

 

I may look into a DO meter at some point, but I have other more important stuff to put my money towards currently.

 

The door of the laundry is always open and where that photo was is pretty much right next to it (door behind where I was standing), so it's pretty ventilated there. I find it easier there because I can rinse off the oxy wand straight away - I don't like putting liquid on it when it's not running because it'll end up inside the stone. There's definitely nothing in there that could spark, though.

 

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