Minimising oxidation

[Ferg]

Good to know it works in theory! Any tips or pitfalls? Is the beer fully carbonated by the time it reaches the tank?

 

[dblunn]

Where did you get the stone with the 1/2" BSP plug?

 

[wobbly]

I experience something similar with my Williamswarn ie loss of flavour and aroma from hoppy beers after a couple of weeks when the tank is about half empty. If I bottle some of the same beer at the end of fermentation with a counter pressure bottle filler that also facilitates purging some/all of the air from the bottle before filling, those beers are fine after a month (they don't last any longer than that) so this leads me to the view that the loss of flavour/aroma in my case isn't oxidation as a result of exposure to oxygen because the beer doesn't get any oxygen exposure once fermentation starts but rather the flavour/aroma is being absorbed into the Co2 in the ever increasing head space
\
Just my 2c worth

Cheers

Wobbly

 

[Ferg]

Where did you get the stone with the 1/2" BSP plug?

http://www.ebay.com.au/itm/2-Micron-Diffusion-Stone-1-2-MPT-1-4-Barb-Inline-Carbonation-Aeration-Homebrew-/172452344649?hash=item2826f5f349:g:RYUAAOSwUKxYZkrB

 

[tugger]

The only advice I can offer is to keep a constant pressure in the receiving vessel (1.5 bar) and try to maintain a constant beer flow rate.
If your flow slows your co2 will rise.
After a few tries you will know your pressures and hit your co2 target every time.
This usually ends up around 10 to 20 parts per billion of dissolved o2.

 

[Danscraftbeer]

I experience something similar with my Williamswarn ie loss of flavour and aroma from hoppy beers after a couple of weeks when the tank is about half empty. If I bottle some of the same beer at the end of fermentation with a counter pressure bottle filler that also facilitates purging some/all of the air from the bottle before filling, those beers are fine after a month (they don't last any longer than that) so this leads me to the view that the loss of flavour/aroma in my case isn't oxidation as a result of exposure to oxygen because the beer doesn't get any oxygen exposure once fermentation starts but rather the flavour/aroma is being absorbed into the Co2 in the ever increasing head space
\
Just my 2c worth

Cheers

Wobbly

I'm with these thoughts too. I brew closed system and find it a little hard to believe its O2 that diminishes my hop aroma's. Unless I over oxygenate at pre ferment?
Admitting that I do get the loss in aromas too like others mentioned.
Is it an old brewers tale that beer will have a layer of Co2 that self protects it when fermenting, never disturbed and transferred gently. As a layman I thought purging a keg with co2 isn't blasting and wasting co2 but pressurize it and let it sit. The O2 is lighter so disconnect the Co2 and then release with the PRV. o2 being lighter should be expelled out the top etc. Then pressurize it again, disconnect, let sit, release. This just means your not blowing the contents around and mixing the co2 with whatever o2 is left. If that makes sense.
I'm hooked on the idea of longer term hop aroma though. But to purge with water? what water? is it pre boiled and deoxygenated and sterile as well?

I like the Star San idea but there's still o2 in the water and you need to ensure you expel every dribble in my fussiness. I don't like any star san in my beer and bubbles of star san either because its probable got o2 in the bubbles too. So I actually final rinse with boiled water to get rid of the bubble plumes before I Co2 purge then pressure transfer.
To purge with Sanitizer I'll need another keg to store it, that's no biggy. And tip the keg upside down to release as much starsan dribble I can.

Good topic guys I'm sure well find the Holy Grail some day.

Edit: typos, clarification, layman's delayed proof reading.

 

[Lyrebird_Cycles]

the flavour/aroma is being absorbed into the Co2 in the ever increasing head space

I hadn't thought about that, but looking at work on headspace volatiles in hopped beer it looks to be possible.

 

[Danscraftbeer]

^ Then an assumption could be to bottle or can the draught beer when its green. Is that how the big craft boys do it?
That is something I've been tempted to do many times but just thought (its only going to get better in the keg anyway yeah?)
I've been blown away with hop aroma and flavour in my green beers. Then it does mellow and hop aroma and flavour does regretfully diminish.

So maybe that's the prime time to package in a Craft Brew thang. But I can only bottle into PET bottles for now. That may do it.
To think that I got into kegging to get away from bottling only to keg then bottle. :lol:

This thread now probably veering from topic but hey. Its a good conversation.

 

[Coldspace]

Ha, yeah kegging then back to bottles
Yeah, aromas disapating into the bigger keg space as time goes on.

I was reading about this technique that was done in the USA.

The oxygen in water would stay dissolved, and as the co2 pushes it out 99% would be gone leaving the volume replaced with 100% co2.

Might be over kill, but

I do agree that leaving that 50 odd mls of starsan in the bottom that can't be pushed out of the dip tube may be an issue.

Is starsan just water type food acid, they use phosphoric acids in soft drinks like coke etc, is it similar type?

I always shake out starsan residue but never have rinsed it off, hope I don't get some exotic disease long term from its use

Would this small amount be harmfull or would it disapate and ph adjust out once beer goes in?

I usually just spray everything in starsan then shake the residue out, then purge , then fill.

Would it be best to spray starsan, then fill with water, push out then fill. ?

Are our local town water supplies treated enough to not re-infect the keg with a bug doing this?

I'm not too worried about water wastage , as I usually wash all my brew gear next to our pool, so the water goes into the pool to help keep it topped up. Especially in hot sunny qld ATM l

Might , if I get some time one day and could be ****** doing it lol, brew real hoppy APA from one batch, fill 2 cornies, one the traditional way, the other with this method, and drink them down evenly over a couple of months and see if there's any truth behind this.

Maybe myth busters or better still , brulosphy have a crack at it

Cheers

 

[Danscraftbeer]

No your on the right track brewer. Thinking! Drinking! What a powerful 10,000 years + philosophy.

 

[wobbly]

^ Then an assumption could be to bottle or can the draught beer when its green. Is that how the big craft boys do it?

It's highly unlikely that they would have the finished beer sitting around in a half empty brite beer tank for a few weeks before they bottled/canned or filled kegs.

Not sure what the craft brew pubs do but then they would most likely be turning there brite beer tanks over in less than a week

Cheers

Wobbly

 

[wobbly]

On the subject of purging the corny with co2 here is a post by Dr Smurto from another site that I have taken the liberty to copy and post here

No offence meat towards anyone just that this test by the good Dr indicates that purging is a lot harder to be effective than most commonly thought

Cheers

Wobbly



I've done the experiment in the lab measuring how long it takes to displace all the oxygen in a corny keg. Oxygen sensor in the lid, high pressure nitrogen through the dip tube so flushing from the bottom up out the PRV.

Took 2-3 minutes.

So venting isn't going to be an effective way of displacing the oxygen unless you keep the PRV open for minutes.

No need for racking IMO. The risks far outweigh the (perceived) benefits.

 

[Danscraftbeer]

On the subject of purging the corny with co2 here is a post by Dr Smurto from another site that I have taken the liberty to copy and post here

No offence meat towards anyone just that this test by the good Dr indicates that purging is a lot harder to be effective than most commonly thought

Cheers

Wobbly



I've done the experiment in the lab measuring how long it takes to displace all the oxygen in a corny keg. Oxygen sensor in the lid, high pressure nitrogen through the dip tube so flushing from the bottom up out the PRV.

Took 2-3 minutes.

So venting isn't going to be an effective way of displacing the oxygen unless you keep the PRV open for minutes.

No need for racking IMO. The risks far outweigh the (perceived) benefits.

Like on reference to burping a keg (3 times etc) its just the small headspace. For an empty keg its a waste of nitro or co2 because of the turbulence that mixes it all.
This why I ask below question. co2 is heavier than oxygen. So what about my thought to purge is to pressurize keg with co2. Then let it sit and settle.

Q: How long would it take for the co2 to settle to the bottom on an 18lt keg?
So that when you release the PRV it should expel the oxygen that should be sitting on top?
It may be stretching but any technique to improve on etc.

Otherwise its back to the full flush with San. I could probably get around to that.

 

[peteru]

Q: How long would it take for the co2 to settle to the bottom on an 18lt keg?

That will never happen, because of diffusion.

 

[Chridech]

There can be no waste in doing this method. I have a premixed 25L container of starsan. I fill a keg with it and then use co2 to push it straight back into the original vessel.

Excellent idea. How many uses do you get out a 25L container of Starsan? Is there any value in checking its pH periodically to determine that is still has sanitising ability? I saw comment on another thread a few months ago that pH should be below (?)3.5.

 

[Danscraftbeer]

^Correct.
I have measured mine fresh mixed. It read pH 2.5.
If everything is clean then you can get many usages. If its obviously clear then its good. Cloudy means its soiled somehow and needs ditching.

 

[peteru]

Will ditching cloudy starsan (let's say at pH of 4.0) on a 30+C day on a lawn kill the grass?

 

[Chridech]

Will ditching cloudy starsan (let's say at pH of 4.0) on a 30+C day on a lawn kill the grass?

Ha ha! I want to know too. SWMBO obeyed already goes crook at me for killing the lawn with hot wort dregs and perc.

 

[peteru]

I got in the ********* when I tipped all the spent grain, hot break, cold break, fermenter trub and yeast cake in the compost on top of some fresh lawn clippings, then went away for a week. When we got back, the compost smelt like a family of rats died in a vegemite factory. Luckily, turning the compost a couple of time over the next few days solved the problem, but it was rather nasty.

 

[nosco]

Will ditching cloudy starsan (let's say at pH of 4.0) on a 30+C day on a lawn kill the grass?

I dont know from personal experience but I have seen pictures that other people have posted of dead grass patches from tipping Starsan on the lawn.