CO2 Regulator for transfers

[Rosie]

Guys,

I'm pushing beer about the brewery with CO2, for instance from bright tank to kegs...I'm doing this on a small scale 2hl (1 barrelish) and using a bog standard dispense regulator and tank. On the last 50 litres or so, my tank has a quarter inch of ice on it, regulator is freezing up and the flow rate slows to nearly nothing.

So,

* Am I going to damage the equipment, brewery, or myself with this practice?

* Is there a special regulator I need to make this work?

Cheers,

[RobZamites]

Basically, you're drawing on the tank too hard. Special tanks exist with heaters in them to prevent dry ice build up, other places with hard usage utilize a surge tank, which allows the main tank to keep up while you draw CO2. Best advice? Consult an industrial gas representative.

[jipjanneke]

As long as the kit you are using has been professionally supplied (i.e. not home-made using cast steel components, for example) you should be ok.

Note that embrittlement (and therefore danger of rupture) of standard steel occurs at about -29oC (-20oF). You won't be getting enough dP across your regulator to generate such cooling (the ice is literally frozen moisure from the air, and indicates temperatures below 0oC/32oF, but hardly near -20oF). My little simulation shows that to get to -20oF from a starting temperature of 68oF, you'd need to have at least 545psi in your bottle. This won't be the case when the bottle is nearly empty!

Probably, your components are made of brass or stainless, which will improve the situation for you and so you are in no danger of doing anything or anyone any damage (unless you press your tongue against the ice!).

The ice will block the flow of CO2 until it melts again - spray some water mist over the regulator and this will help in a bind.

[BelgianBrewer]

There are a couple of options:
* Go with a high-volume regulator.
* Buy a small electrical heat strip to keep temperatures up.
* Add a regulator in parallel to the one you already have. This will spread the flow over the two regulators and reduce or eliminate ice build-up.

BelgianBrewer
www.sbmbrew.com

[Sir Brewsalot]

...or use a pump for the x-fer.

[RobZamites]

...or use a pump with a VFD on it as to avoid massacre to the proteins in your finished beer...

/just sayin'

[Sir Brewsalot]

Good point - though, I've been using a pump to x-fer for a year and a half now. (Not that I know any better.)

I'm a bit off the original thread here, but...

If there was a negative effect on the beer/proteins, how would that present itself in the finished product? Not that I use these either, but don't filters and bottle fillers pump beer?

Cheers,
Scott

[RobZamites]

It's probably a "momily" (A piece of advice you mom gave you that isn't actually true) that pumping full-bore will ruin your beer, it's just what I've been taught, so I try and minimize it. True that filters (especially the Velo brand :) ) use pumps to move beer, and frankly, I haven't noticed a real difference in finished head retention or anything else. It might be an interesting experiment to ferment two batches (say, in this case, a fruit beer), moving one to the secondary fermenter and fruit with a pump, the other with CO2, and seeing if the finished beers are different...

Hmmmmm....

[Larry Horwitz]

Issues with pumps not having VFDs are usually related to shear and O2 pickup...both of which can be avoided with careful practice. VFDs are very nice, but not required for world class beer.

for your ice problem try this old school trick...put a hose on it! We used to just hang the end of the hose on the regulators adjustment post and run it at a slow stream. Does wonders, and you don't need fancy equipment.

if you are pumping you could also use an atmosphere exchange hose...for tanks just run a clean hose from CIP arm to CIP arm. Keep the whole system under a bit of pressure (i'd say about 1/2 Bar or 7ish psi) and pump away. As the donor tank empties gas will be pushed back in. Also cheap and nifty.

good luck

[Moonlight]

My Mom never told me nuthin' about pumping beer, but I am a firm believer that a gentler transfer makes better beer.
As for problems with CO2 tanks freezing... BAD NEWS! The DIAPHRAM is Fragile!!! (and the safeties get plugged with ice.) I have had problems with regulators freezing and allowing dangerously way too much pressure thru. Been thoroughly scared before but usually caught it before beer tanks ruptured.

Even Micromatic has a regulator designed for more flow, but if you are icing up the tank and regulator, you need more than just that.

You can get an inline heater from your CO2 supplier that threads on between tank and regulator body and runs on 110V. They work great and are not too expensive. I hope there is one today that has a thermostat so less attention is required.

Belgian Brewer said this:* Buy a small electrical heat strip to keep temperatures up. And it is probably the cheapest option.
I use regulators with aluminum fins to solve the freezing but they are expensive as ...

If your CO2 tank is in a cold room, you may even solve your problem by moving it to a warmer location. I am afraid of the idea of using water on a regulator unless you find one that is designed for water contact.

Regulators are SAFETY equipment! All kegs are marked with the pressure warning stamp and all couplers have pressure safeties today because someone killed themselves when a regulator overpressured a keg a couple decades ago in Ohio. The keg ruptured itself and the person's body. Don't risk that to your kegs or your body.

[RobZamites]

Could someone clarify the use of a balance line between fermenter and serving tank for the xfer of finished beer? I currently pressure up the FV to about 8 psi, the SV to about 5 psi and start the transfer, adding CO2 to the FV, while slowly bleeding off gas from the SV. What benefit does a balance line serve?

[Larry Horwitz]

Hey Rob.

Balance line is easy. Get a hose...what hose you will use will be determined by what kind of connection you have on your CIP arm or gas inlet / outlet. If you have a 1.5" Tri-clamp valve on the cip arm of your bbts and FVs you could use brew hose, or something like 1/2" braided hose with tc ends. Pressure up both tanks to more than 5psi but less than 15psi. Hook your hose to the CIP arm of one. Vent that tank a bit to purge the line. Hook the other end to the other tank's CIP arm. Open up both sides...the pressure should equalize. Pump away.


You don't really need that much pressure...unless the beer is carbonated. I just keep it up around 5 for safety...and cause most pressure guages on these tanks aren't very accurate near zero. You really don't want to suck in one of your tanks.

cheers

[RobZamites]

Larry, thanks for the input -- I generally cap off the TC fitting on my CIP arms and have quick connects for the gas -- also, I run from FV's upstairs to SV's downstairs in my cellar, so I don't pump anything, but rely on gravity/gas pressure to move things along -- would a balance line still be a benefit?

[Sir Brewsalot]

Rob,
That sound like a PERFECT situation. Just gas up the server to MATCH the FV pressure, open the balance line, open the beer line and let the beer flow. No bleeding required!

Remind me to install a basement.

Cheers,
Scott

[Moonlight]

By saving and "reusing" the old beer headspace you may not be venting off some undesirable aromas. Smell the gas and decide for yourself. I suspect this is especially true with lagers. Of course if there are any undesirable creatures in your aging tank, they would be sucked into your fermenter.

[Larry Horwitz]

???????? the off gas from the brite tank is going into the FV....which you will be cleaning when it's empty. No issue with venting volitiles. The goal here is to move your product without add O2 or crushing a tank. If your beer isn't finished you shouldn't be sending it to the finish cellar.

[Sir Brewsalot]

Had the same thought initially - then I thought: Maybe he means capping the fermenter prematurely will keep the "bad" gas captive?

On a related note, I thought of pressurizing a devoted (to a fermenter) bright tank with CO2 from the ferment, but have elected to forgo this practice for similar reasons, and spend the $4.00 on CO2 instead. Plus, I'm never really that well-planned on a brew day to set this up.

Scott

[Moonlight]

So in retrospect, I can't say I see the problem I saw before...Yes, there are/can be unpleasant volatiles in the bright (especially in lagers). And one can blow creatures from the bright headspace into and on the top of the finished fermented beer, although chances are slim. The fermenter would be cleaned but the beer could get contaminated. Not all that likely, but worth remembering if the bright wasn't so tasty.
1000 bonus points to the two sharp guys from PA!

[jipjanneke]

On a kind of related note, does anyone pre-purge their empty tanks with CO2 before pumping into to rid O2? Piston purging would potentially help here - charge up to a few psi with CO2, dump/vent, then charge up again and then pump in. Just wondering if anyone actually does it?

[RobZamites]

I do -- I ALWAYS purge/pressurize my serving tanks prior to moving beer into them.

[Larry Horwitz]

Every time. If you don't purge the tank with CO2 from the bottom up for plenty of time you might as well be moving your beer from one take to another with a bucket. It's an o2 nightmare. i've seen orbisphere tests where the beer picks up so much o2 being transferred into an unpurged tank it would oxidize in like 1 week.

purge completly every time and your beer will be better.

[mtbc]

Any thoughts regarding standard practice for tank purging?

Based on Fix's "Analysis of Brewing Techniques" we purge by pressurizing our brights to 15 psi, filling from the bottom. We allow them to sit for half an hour and then exhaust from the CIP mast. The thought being the CO2 settles out of the gas mix and the O2 gets expelled first.

I suspect this is not an efficient use of gas. It seems various methods of purging a tank with gas could be evaluated with an O2 meter. I've never seen this discussed, and lacking an Orbisphere or Mettler-Toledo I've never done it myself.

How do *you* purge?

[RobZamites]

Well, being unable to afford o2 meters or the like, I purge by applying co2 to the stone and bleeding out the CIP arm, with the valve goosed pretty closed (but not completely), and let 'er run for 7-10 minutes. When I check, I put cupped hands under the CIP port and smell -- if my nostril hairs burn, I know I have a SV full of co2 ;)

[Sir Brewsalot]

Funny, I also use "Rob's Nose Hair Method". (Maybe he'll become famous for this).

My thinking is that I'm not getting ALL the O2 out, but figure that the concentrations are going to be much higher at the bottom, and since the top portion gets pushed out of the tank as the beer goes in, I should be in decent shape.

To answer an earlier question, I always move into a pressurized bright since I typically cap fermenters to capture the last bit of CO2, so I need a pressurized destination to prevent foam-out. I also use a pump for the x-fer, but I think I said that before...

Cheers,
Scott

[Larry Horwitz]

hey,

the "Rob's Nose Hair Method" sounds decent, but you'd be blown away by the amount of o2 that's still in your tank if you just pressurize and go. Even with the smell manuever there is still a good deal of O2 in there. I'd purge at least 10 mins for smaller (10bblish) tanks. also, the co2 sinking to the bottom thing is all smoke and mirrors / old wives tale. First off....it doesn't really work that way. also, consider the volume of CO2 you're using. When you don't purge all the way you will oxizide your beer by filling the tank. I was talking with someone (Bamforth? can't remember who) who made the very valid point that there is no research to back up the co2 sinks claim...but there is a ton of oxidized beer out there refuting it.

also...I hate to speak ill of those who have passed, but I'd ditch the Fixx book and get into some reading by brewing scientists (kunze, declerk, etal) Fixx was a math professor. He may have been a damn fine homebrewer but he wasn't a brewing professor......

[crassbrauer]

I agree.

CO2 is heavier than O2 and will sink to the bottom after a while, hence the deaths every year among Austrian farmer/vintners in their wine cellars. There is, however, in most brewery situations a large area of mixed gas in tanks. A lot of brewers are under the false notion that CO2 sinks like lead in their freshly purged brewing tanks.

Also, I've seen some false info and even formulas written different ways in Fixx's books. I respect(ed) him a great deal, but wouldn't use his books as the gospel truth.

[kugeman]

If what you guys say is true (and I'm sure you know more about this then I do :o ) then how much purging is sufficient? I've always...
1)taken my 7bbl tanks up to 10 psi, purged from the bottom, then
2)taken them up to 15 psi, purged from the top and
3)pressurized to 15psi and set up my filter.

But it sounds like this isn't good enough to really get rid of O2...

what would be your suggestion since cleaning under pressure is unfortunately not an option for me?

thanks in advance for any replies...

[beertje46]

You could always fill your tank, from the bottom, with sterile, de-oxy'd water until it flows out the CIP arm. Push the water out with Co2 and charge to 15 psi and filter. ;)

[Sir Brewsalot]

Hutch,
Before you change your procedure, let me ask you: Do you have any oxidation problems?

"Good Enough" may be good enough.

Scott

[crassbrauer]

Just to add my experience to the sound advice in the above two responses:

In a brewpub, which kegged as well, I always just let the CO2 seep ever so slowly in from the bottom of the empty tank with the CIP arm open. When I "smelled" a strong level of CO2, I'd close the tank then top it up with a small amount of pressure. This I'd repeat for the same amount of time the following day. I think this allowed for the mixed gases to separate out somewhat. I never had any problems, even with kegged beer, which would sometimes not be consumed for a couple of months. This requires a little time between batches. This I did at pretty much atmospheric pressure. Pressurizing the tank up to 10 or more psi does increase the amount of CO2 relative to the air. The violent nature of this type of rapid purging, however, doesn't allow for any separation to occur.

[Larry Horwitz]

hey Hutch. Good to hear from you. Did you get home safe from Ommegang? Dude, what a great time! Also, you going to GABF? We are looking for a 4th for our Long's peak trip if your interested.

O2....I'd purge from the bottom for at least 10mins for your tanks. Try the "sniff test". You should do it a little longer then just topping off. Doesn't cost much (time or gas) and your beer will thank you. Don't forget to purge your hoses and filter too!

the answer to the question "is your beer oxidized" is; yeah sure, you betcha. Unless you've measured it and determined your airs are low I'd bet a sawbuck they're too high. Hutch's beers taste great and sell fast....so the level of o2 may not be contributing to long term instability ('cause the beer is gone) but that doesn't mean they're not oxidized. the question should be, 'how important is it that your beers are oxidized'

for pub brewers this could be less of a consideration.... but maybe not. Just something to think about.

[Greenbrewmonkey]

Hello all,

Just a thought about gas dynamics relating to Crassbrauer's comment on allowing time for the gases to separate. Correct me, but gas law dictates that a mix of different gasses will come to an equilibrium state. Meaning all gas molecules and concentrations will be equal at all points. More or less. So two gasses left overnight will not separate as liquids will, but rather mix together. Perhaps I am wrong on this? Chem class was oh so very long ago. Or I misunderstood the post? But all those cylinders of blended N2 / CO2 never seemed to first over carbonate then flatten the beer, so...

I would think the best procedure would be a relatively quick purge / vent procedure that would not allow the gasses to combine.

But again, no O2 meter. So no real data.

Cheers,
Ron
Jolly Pumpkin Artisan Ales

[crassbrauer]

I'm no physicist, but I do know why CO2 settles out:

Density of CO2: 1.98 kg/m³
Density of O2: 1.429 kg/m³

The unfortunate experiment I mentioned above, conducted seasonally by the Austrian farmer/vintners, along with the numerous other industrial accidents involving CO2 in low-lying areas or in tanks verifies this. Cold air and warm air also fall and rise respectively.

I believe what you're referring to (my memory of this is also a bit rusty) is that the same number of molecules will be present in a given volume anywhere within the tank, given that the temperature is the same all over. More clearly stated: With all ideal gases at the same pressure, the same temperature and the same volume, the same number of molecules are present. (This is known as Avogadro's law, I think.)

[mtbc]

Larry makes a couple good points. Our gas supplier agrees the 'CO2 settling model' is inaccurate in the case of purging. He says that mixed gasses just don't settle out that quickly. However it's a comforting old wife's tale and we cling to it here in lieu of a better model. I also agree with your comments regarding Fixx. I admire him for championing an analytical approach to home/craft brewing, but a lot of his conclusions do not scale up. His book *is* the only one I've found that advises a specific tank purging technique for CO2, though I guess if you rule out settling you're only reducing the O2 by half.

I made a quick review of the bookshelf and found the following. MBAA's Practical Handbook recommends "...purging for a period of time..." in addition to what it calls 'water gassing' or purging with de-aerated, sanitized water. Kunze makes several references to minimizing O2 uptake with the use of “degassed, biologically clean water” and none to CO2 purging. Malting and Brewing Science vol. 2 says “...a thin blanket of carbon dioxide may be readily produced above the beer in the donor tank, and a top-pressure of air used to move the beer out of the tank. A small amount of carbon dioxide may be injected into the main as the beer passes to the recipient tank, in such a way that it readily escapes as a gas when the beer enters the tank. Again a thin blanket of carbon dioxide covers the beer, this time in the recipient tank.” Alternatively it suggests water gassing. Siebel's notes say a tank can be “...purged with CO2, but this is an inefficient and ineffective way to achieve the CO2 atmosphere. The most effective way is to fill the tank with water, push the water out with CO2 and the fill with beer.”

The literature seems to agree with David, though I sure don't want to work out the de-aeration, UV sanitizing and storage problems that approach presents. It seems with a proper O2 meter you could pretty easily say “blowing 3 psi CO2 into your 15 bbl tank for X mins. results in a O2 level of Y”.

On top of oxidation concerns our CO2 is barged in rail cars from Seattle and at $0.85/lb I'd sure like to use less of it.

Take care all.

[Moonlight]

If gases separated over time, we wouldn't have the mixed atmosphere we breathe-entropy is stronger than the different densities. It is more like the "strong" mixed drink where the liquor is poured on the top...it will only slowly diffuse until it is mixed. Ditto a black and tan. If your CO2 can go in so non-turbulently from the bottom, there will be less mixing of the gases for a while. I know that in my cold room with the blowers off, after opening a tank, the CO2 is dang strong near the floor as it is heavier, but not after a half hour or less.
Without expensive CO2 meters, it seems like gentle (maybe by stone?) purging from the bottom has got to help especially with "Rob's Nose Hair Method." I use the same method after the tank is full of beer after three high pressure purges. Purging after filling may be more cost effective especially for that CO2 shipped in from Seattle.
If your nose doesn't burn then there IS oxygen left, but burn doesn't prove it is all gone. I would be more concerned about air in bottles than a brewpub.

[crassbrauer]

I agree. That CO2 settles is indisputable. How it does it and how fast are the questions. The model accepted by much of the brewing world is very simplified, i.e. in reality there's a lot more mixing, and settling occurs more slowly. Obviously, the CO2 has to far outweigh the air to achieve much, and regardless, the CO2 is never completely free of air. I guess if one were to grab the old physics book, it'd be possible to figure the time it takes for CO2 molecules to settle out in an undisturbed tank of CO2 mixed with air under certain conditions. Sorry, I don't have the time to play with the formulas right now... ;)

[Larry Horwitz]

Great thread gang. love the discussion.

two things...just to clarify my position on CO2 settling: I do get worried about CO2 in the cellar near the floor (there is some settling, no dispute) I also know that if my tank isn't purged totally it'll have O2.

anyway....so I was talking with another brewer friend of mine and he uses a method I've got to tell you guys about. He routes the offgas from fermentation into his clean empty bright tanks. He just leaves the CIP arm open on the bright. Very elegant, very cheap, very effective. I'm gonna try this one out!

[crassbrauer]

CO2-recycling is used widely in Europe, and it's a wonderful way to save money, only if you clean it and filter it first. There's all sorts of crap in there. CO2-recycling equipment cleanses the CO2 numerous times, using various methods before it's ready for use again in the brewery. Just running a hose straight to your bright tank sends anything that gets carried out with the CO2 or any of the other volatile substances created during fermentation right into your bright tank - stuff that you don't want coming into contact with your beer. Plus you're creating a substrate for infection. Your wort-/beer-spoilers will love you for it. Not cleansing it can result in infection from lactos, pedios, even other weird microbes drawn to the particular mix of substances found in fermentation blow-off. Besides, beer maturation involves getting rid of a lot things which give the beer a "young beer" flavor (acetaldehyd is commonly cited, but countless other substances are in there, like H2S, DMS, etc.). These things should be allowed to leave, not be sent to your bright tank. Odd off-flavors and aromas have resulted from reuse of funky CO2. There's a reason this is not common or mentioned in any books dealing with relatively small-scale brewing. It's also the reason brewers buy CO2 if they don't have the equipment for recycling it: It has the potential for becoming a very nasty problem.

Don't quote me on this, but I seem to recall a figure that CO2 recycling starts to pay for itself around 200K hl per year. This figure comes from Germany, i.e. where the Reinheitsgebot covers CO2 usage, so it may be even more in the States.

[Moonlight]

Further thoughts on "settling" of gases...a cylinder of Guinness gas doesn't give nitrogen first, then later CO2... it is mixed and stays that way.
As for pressurizing and venting a tank before filling, perhaps we remember from some old chemistry class that atmospheric pressure (0 psi on your gauge) is really 15 psi "absolute" (above a vacuum.) So if you have a bright tank with regular atmosphere of about 20% oxygen, and you pressurize it with pure CO2 to 15 psi on your gauge, then vent the tank down to zero again, you have only diluted the oxygen in your tank by half, or 10% oxygen. It will be 50% CO2, but this is still way too much oxygen to have in contact with your beer. Another identical purge will drop the oxygen to 5% and so on.

[jipjanneke]

Once you start talking about pressurised gas in cylinders (e.g. nitrogen/CO2 cellarmix), the much higher cylinder pressures than at relatively lower fermentation pressures make the density difference negligible. The driving force to settling out/layering depends on this difference alone, so it won't settle.

Also, the time to reach a signficiant settled equilbrium is probably more than any of us will live, plus the power of the Expanding Universe (entropy) will cause homogenous mixing quicker than the settling effect.

Now, don't mistake a strong smell of CO2 as being pure CO2 - the Austrian winemakers will kark it at CO2 levels any higher than 10% CO2. Apparently, it takes only 0.5% to cause an increase in breathing rate (and possibly burning nose hairs?), and only 3% to cause breathing at twice normal rates. Obviously, these are insiginficient concentrations when we are talking about eliminating O2 to avoid beer spoilage, and we would need to do a better job than that.

Reading all of the forum discussion, it sounds to me like the only acceptable method of signficiantly displacing O2 with CO2 is the water-purge method, using new CO2. However, this needs to be traded off against a) the need, depending on how long it takes to sell your beer; b) the beer storage conditions (warm or chilled); and c) any history of problems. Oh, and d) the cost (in time and $$).

Don't neglect the fact that quietly filling your brite tank with beer from your fermenter is necessary so as to minimise disturbance of the liquid/vapour interface - this will help reduce the instance of O2 dissolution in the beer, compared with a fountain effect inside the tank.

Finally, you need to check what the actual limiting factor is - is it O2 dissolved from the brite tank, or through a non-perfect pump seal, or through your filter, or residual O2 from your sterilizer (oxine?), or even hot-side oxidation back at the kettle. If any of these other sources of oxidation are sigificantly neglected, what is the point of getting a perfect transfer environment if the beer is already 'spoiled'? Take a holistic approach.

My 2c worth...

[RobZamites]

What a great thread this is. Yet another reason I love these forums!

[crassbrauer]

Yes, apparently, gases which have been mixed, for example in a cylinder, don’t separate again, given that temperature and pressure are constant all over. I remember learning in ag shop way back in high school that you could put one component of a mixed gas in a cylinder, then another and then roll the cylinders. This didn’t mix them right away, but they would eventually mix. I think we were told to wait a week or two. (These were gases for metal shop.) As mentioned above I’m a little rusty on this, but I think this has something to do with Avogadro, the law of partial pressures, etc.

I think the reason a lot of the CO2 settles out and doesn’t immediately mix in an open fermentation cellar is that there’s a lot of it, and there’s very little movement to speed up the mixing, which takes a little while. It just sort of “flows” out of the fermenting beer and forms a blanket of gas on the floor. (The fans for blowing the CO2 out of open fermentation cellars are at the bottom of the room.) I think that’s why letting CO2 very slowly seep into the bottom of tank works OK for purging a bright tank. As you mentioned, Moonlight, given enough time and/or movement, the air and the CO2 in the fermenation cellar would become homogenously mixed, but I guess they’re not given the chance.

As done in numerous college chemistry classes, if you fill balloons with different gases, for example, helium, CO2, air and xenon gas (or some other heavy gas), they’ll rise or sink according to their density compared with air. If you pop a helium balloon, though, the gas disperses around the room, because the room is huge compared to the tiny volume of the balloon. One thing this thread speaks for is the importance of some knowledge of physics and chemistry for brewers. I’ll put dusting the cobwebs off of those subjects on my long list of things to do. :)

As already mentioned a few times in this thread, the first question to ask yourself before taking drastic measures is: Do I have an oxygen problem, and if so, where is it?

[Moonlight]

If you like toys, check out the Oxy/Nitro gas meter in the Micromatic catalog. It is a bit crude but basically tells you the amount of CO2 in a venting gas, so you can see how effective your purging is.