Re: Conical question – closed transfer

Thu Jan 26, 2012 9:34 pm

darkalex wrote:Well my main reason for going with a conical was the ability to drop trub and collect yeast for reuse, without the pick up of oxygen that you have with buckets or carboys. The 2-stage temp controller and ability to conduct a closed transfer clinched it for the More Beer conical.

Those are all good reasons.

darkalex wrote:AJ, in terms of the flavor in the finished beer both initially (say a month out) and looking more longitudinally, how would a closed transfer from fermenter to keg compare with gravity feeding and simply purging keg and transfer tubing with CO2?


I think it would depend on how well you purged the kegs. If you do it by pushing water out that's better than just pressurizing with CO2 and bleeding as discussed in an earlier post. As to how beers packaged in the two different ways would compare - really can't say. I've been doing counter pressure transferring for so long I can't remember what the beers I made before I started doing it tasted like except that they weren't as good as the one's I'm making now but there have been lots of other improvements in my methods beyond CP transfer since then. I'm sure you know what the effects of staling are (cardboard, aldehyde, winey, diacetyl, souring...) and theoretically the better you exclude oxygen the longer you can go with less of those spoilers.

darkalex wrote:I did not bother with a closed transfer with my first batch, a sweet stout which tasted pretty awesome. It's in my chest freezer now around 37F. I believe that it should be fairly stable. Do you agree?


Can't agree or disagree because I can't be there to taste the beer. And even if I could you should be the one to answer that question. Certainly stout, with its strong flavors, should be able to mask staling better than a delicate lager so you have an advantage there.
ajdelange
 
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Re: Conical question – closed transfer

Sat Jan 28, 2012 5:08 am

When using the CO2 bleed technique for purging the keg prior to filling, doesn't the CO2 stratify near the bottom of the keg, since it is a heavier gas than O2? When the valve is subsequently opened are you not selecting for the lighter O2 near the top of the keg? Or should we assume the gases are uniformly mixed.

Also, do you think it's a good recommendation for beginners to target a beer style that is more resistant to oxidative stress, beers that have a lot of darkly kilned malts in them. Generally these brewers are using plastic buckets, racking canes, and conducting an open transfer.

And for a delicate light lager style, will re-yeasting in the keg with priming sugar help burn the O2 introduced during the transfer and preserve the beer long term?
darkalex
 
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Re: Conical question – closed transfer

Sat Jan 28, 2012 7:25 am

And another thing: Won't the lighter and smaller O2 effuse preferentially through the pressure relief valve. So upon repeated purgings, are we not selecting for the heavier bulkier gas?
darkalex
 
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Re: Conical question – closed transfer

Sat Jan 28, 2012 8:33 am

darkalex wrote:And another thing: Won't the lighter and smaller O2 effuse preferentially through the pressure relief valve. So upon repeated purgings, are we not selecting for the heavier bulkier gas?


I believe Graham's Law of effusion applies in this case. Please correct me if I am wrong, but the lighter gas should exit the keg at a greater rate through the pressure relief valve.
darkalex
 
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Re: Conical question – closed transfer

Sat Jan 28, 2012 2:51 pm

darkalex wrote:When using the CO2 bleed technique for purging the keg prior to filling, doesn't the CO2 stratify near the bottom of the keg, since it is a heavier gas than O2? When the valve is subsequently opened are you not selecting for the lighter O2 near the top of the keg? Or should we assume the gases are uniformly mixed.


When you turn on the CO2 you can hear it whooshing into the keg so I expect things are pretty turbulent in there and at least initially the gasses are pretty thoroughly mixed. After letting the keg sit undisturbed for some time things might separate but I have no idea how long it would take to reach any particular level of separation.

darkalex wrote:Also, do you think it's a good recommendation for beginners to target a beer style that is more resistant to oxidative stress, beers that have a lot of darkly kilned malts in them. Generally these brewers are using plastic buckets, racking canes, and conducting an open transfer.


Yes, definitely.

darkalex wrote:And for a delicate light lager style, will re-yeasting in the keg with priming sugar help burn the O2 introduced during the transfer and preserve the beer long term?


Yes, absolutely but the less O2 in there for the yeast to consume the less of the yeasts reducing power gets taken away from, for example, diacetyl reduction.

darkalex wrote:I believe Graham's Law of effusion applies in this case. Please correct me if I am wrong, but the lighter gas should exit the keg at a greater rate through the pressure relief valve.


Graham's law just says that the velocity of the particles is inversely proportional to the square root of their masses so that a ligher particle covers more distance in a unit time and thus has a higher probablility of reaching the outlet port than a heavier one. The ratio is the square root of the masses of the particles in this case sqrt(44/32) = 1.17 so oxygen would have a 17% advantage in this regard. I'd think that would be a second order effect.
ajdelange
 
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Re: Conical question – closed transfer

Sun Jan 29, 2012 9:49 am

So due to its molecular weight, O2 has a greater probability of exiting the keg. How does this probabilty change with each subsquent venting and purging of the keg? Is it simply multiplied by the number of times purged? Or does the O2 loss depend on the concentration of O2 and/or other gasses in the head space? If so, does the probability decrease, with each purging, since there is less of it around? Describe what you mean by 2nd order phenomena.
darkalex
 
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Re: Conical question – closed transfer

Sun Jan 29, 2012 10:13 am

ajdelange wrote:Well, if you stood up in front of, for example, my brew club and made that statement all the experienced brewers would laugh.


Some people are hopelessly locked in linear thinking and allow themselves to imagine that the universe of acceptable possibilities is already constrained by the box in which they have settled themselves.
The box is not the universe. It's just the box.

I'm addressing members of that universe that want to get into the subset that makes the best beers.


You are merely stuck in a box and telling yourself that you have a hotline into cosmic truth and reality.
HEY~!! It's a hobby~!! It's NOT supposed to make sense~!!
Cliff
 
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Re: Conical question – closed transfer

Sun Jan 29, 2012 11:16 am

Not sure if Oxygen loss from the head space in a corny keg upon repeated purging and venting confers to linear relationship. I think that is what we are trying to establish.

Cliff wrote:
ajdelange wrote:Well, if you stood up in front of, for example, my brew club and made that statement all the experienced brewers would laugh.


Some people are hopelessly locked in linear thinking and allow themselves to imagine that the universe of acceptable possibilities is already constrained by the box in which they have settled themselves.
The box is not the universe. It's just the box.

I'm addressing members of that universe that want to get into the subset that makes the best beers.


You are merely stuck in a box and telling yourself that you have a hotline into cosmic truth and reality.
darkalex
 
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Joined: Tue Jan 25, 2011 1:30 am
Location: Gainesville, FL

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