Should I cut my dip tube?

[chipmunk]

I recently bought some pin lock kegs and have some questions about kegging. I‘m planning on doing a closed transfer after fermentation is complete, and then cold crashing under pressure. I’m making an octoberfest style of beer, and I did add Irish moss to the boil. A couple of questions:
- do I just add gelatin prior to the transfer, should I wait until it is already cold, then open and risk oxygen exposure, or just skip it cuz Irish moss will be good enough?
- much sediment will I get from just the crash? Is it worth cutting the dip tube? How much should I cut? If I do, will I lie awake at night lamenting the wasted beer?

 

[passedpawn]

Haha, good post. I don't strictly practice the LODO techniques, so my answer likely will conflict with those. I like to get the beer as clear as possible BEFORE transferring to keg. I've had too many clogged poppets. So I suggest cold crashing the fermentor to 33F, adding gelatin, waiting 2 or 3 days, transferring as carefully as possible to keg. Don't cut dip tube.

 

[VikeMan]

- do I just add gelatin prior to the transfer, should I wait until it is already cold, then open and risk oxygen exposure, or just skip it cuz Irish moss will be good enough?

Gelatin works best when the beer is cold. But I never use it unless the beer actually needs it. And since you're making a lager, I assume you'll be lagering, which will allow more stuff to settle out.

- much sediment will I get from just the crash? Is it worth cutting the dip tube? How much should I cut? If I do, will I lie awake at night lamenting the wasted beer?

How much sediment you get from the crash will depend on how much suspended particulates made it into the keg. Since you're doing a closed transfer, can you pressurize your closed fermenter (to avoid sucking air) and cold crash in it before transfer?

Regarding cutting the dip tube, IMO it's kind of a tossup. If you don't cut it, you may "waste" the first pint or two. If you cut it, you'll never pour whatever volume is below the end of the tube. You might also consider using a floating dip tube, which is great for clarity.

 

[chipmunk]

Thanks for the suggestions. I do have one of those Anvil fermenters so I think it should hold some pressure - I recall seeing a video where someone was doing a pressurized transfer on it. So any tricks to that? Just set to 1psi and mcgyver some connection to replace the airlock?

 

[VikeMan]

Thanks for the suggestions. I do have one of those Anvil fermenters so I think it should hold some pressure - I recall seeing a video where someone was doing a pressurized transfer on it. So any tricks to that? Just set to 1psi and mcgyver some connection to replace the airlock?

I would go with 2-3 PSI (gauge) during crashing, but that's the idea. I use a spunding valve in place of an airlock, and then remove the valve before crashing under pressure. Hopefully, someone that has experience with an Anvil fermenter will speak up.

 

[Dgallo]

1psi is sometimes difficult for regulators to manage properly. Depending on what your fv is rated for, you may want to set it for around 5

 

[Stonehenge360]

Planning on cold crashing my CF-5 for the first time this week. Do you guys recommend leaving the co2 line at a constant 5psi or can I just hit it once, disconnect, and cold crash? I have no reference for what psi loss I will have during the crash

 

[Dgallo]

Planning on cold crashing my CF-5 for the first time this week. Do you guys recommend leaving the co2 line at a constant 5psi or can I just hit it once, disconnect, and cold crash? I have no reference for what psi loss I will have during the crash

Keep it connected. Your regulator will kick on anytime it falls below it. This will protect your fermenter from negative pressure damage

 

[passedpawn]

Planning on cold crashing my CF-5 for the first time this week. Do you guys recommend leaving the co2 line at a constant 5psi or can I just hit it once, disconnect, and cold crash? I have no reference for what psi loss I will have during the crash

Easy to calculate this using combined gas law (I think ). The only trick is that V2 (headspace) will increase due to the increase in density of water as the temperature drops (which is what causes suckback when we crash). I've previously estimated the decrease in beer volume (and increase in headspace) to be about 2% when cold-crashing an ale. So, I just called the warm headspace H and the cold headspace 1.02*H. H cancels out and doesn't matter.

For the calculations to work, before you actually do the math, convert temperature and pressure to their absolute numbers by 1) adding 459.67F to T and 14.7psi to P. Subtract 14psi from the final answer to go back to gauge pressure. If Celcius, use 273.15.

P1V1/T1 = P2V2/T2

Need to find P2

P1 = 5 (psi),
V1 = H
T1 = 65 (F)
P2 = ?
V2 = 1.02*H
T2 = 32 (F)

If you start with 5psi, after cold crash (given temperatures above) you'll end up at 3.40 psi.

 

[VikeMan]

^ Pretty cool. But aren't you ignoring the fact that some of the headspace CO2 is going to be absorbed by the beer?

 

[Iseneye]

You dont have to cut the dip tube. When I used to ferment in a keg I just bent the dip tube. Pretty easy to do.

 

[bracconiere]

NO MAN DON'T CUT YOUR DIP TUBE! i'd just count on dumping the first few pours.

 

[chipmunk]

I was playing around with my Anvil with a leak test with soap - the lid starts leaking around the seals at the very lowest controllable range - probably less than 1psi. It kind of makes sense - the lid is over 100in2 in area - so 1psi is like 100lbs pushing against the latches. I like the idea of cold crashing in primary - I think I’ll try using my camelback bladder from mountain biking, fill it with CO2 and use that for the suckback.

Easy to calculate this using combined gas law (I think ). The only trick is that V2 (headspace) will increase due to the increase in density of water as the temperature drops (which is what causes suckback when we crash).

That’s a neat idea - just figuring out the pressure such that suckback won’t ever go negative to atmosphere. One complication would be the solubility of beer with CO2 - which likely depends on specific gravity, temperature, pressure of the beer, and time required for the CO2 to go back into solution with the beer. Do you find that after cold crashing you have pressure left over? I guess in a corny keg you could just pressurize the crap out of it to avoid all the math - hahaha.

 

[Gnomebrewer]

I like the idea of cold crashing in primary

The advantage of cold crashing in the serving keg is that you can transfer with yeast still active so they have more chance of removing oxygen from the serving keg. I like to transfer with a few points of gravity still remaining even though it means some sediment in the keg. No matter how well you purge a keg with CO2, there is still some Oxygen in there.

 

[passedpawn]

^ Pretty cool. But aren't you ignoring the fact that some of the headspace CO2 is going to be absorbed by the beer?

Woops. Back to the drawing board.

 

[Beermeister32]

Is it worth cutting the dip tube?

No

 

[clearwaterbrewer]

Is it worth cutting the dip tube?

I did it a decade ago, it was worth it because even fined beer still deposits a layer on the bottom over time, and I may only have one beer from each tap every few days... but I would swap back for full length ones now, because I use them in a distillery and want every last drop...

 

[passedpawn]

^ Pretty cool. But aren't you ignoring the fact that some of the headspace CO2 is going to be absorbed by the beer?

Well, that only happens if you take it off the gas before the gas has diffused into the beer. IOW, put it on 5psi, wait a week, then when you remove and cold crash the math above will work.

Otherwise, the problem gets more complicated, and I think I'd need to investigate partial pressures - how much of the gas would be in the headspace and how much in the liquid. I'm a stamp collector, not a chemist, and though I'd enjoy taking a stab at that, I would not trust the result.

 

[VikeMan]

Well, that only happens if you take it off the gas before the gas has diffused into the beer. IOW, put it on 5psi, wait a week, then when you remove and cold crash the math above will work.

Yes, of course, because it will have reached equilibrium. Well, maybe not in a week, but at some point. My comment about headspace gas being absorbed by the beer was in regard to the "an I just hit it once, disconnect, and cold crash" option.

 

[passedpawn]

Yes, of course, because it will have reached equilibrium. Well, maybe not in a week, but at some point. My comment about headspace gas being absorbed by the beer was in regard to the "an I just hit it once, disconnect, and cold crash" option.

You're going to make me do the math, aren't you. Can somebody smarter than me please step in and do it first? Remember AJ? I don't think he's around anymore.

 

[VikeMan]

You're going to make me do the math, aren't you. Can somebody smarter than me please step in and do it first? Remember AJ? I don't think he's around anymore.

Well, you could do the math, but I can say from experience that hitting a headspace once with CO2 and expecting it to maintain significant pressure ends in disappointment.

 

[HB2 HughBHomeBrew]

Planning on cold crashing my CF-5 for the first time this week. Do you guys recommend leaving the co2 line at a constant 5psi or can I just hit it once, disconnect, and cold crash? I have no reference for what psi loss I will have during the crash

Yes, you can hit it once at 5 PSI and it will probably drop to something like 2 PSI - which is kinda what all that number-y, math, physics-y stuff was saying. I have found that works with a CF-5 with something like 5 gallons in it to go from 70F -ish to 40F ish. In other words, you won't get to negative PSI in your CF-5 with about 5 PSI prior to cold crash.
If you leave the pressure on, you'll obviously end up with beer that is more carbonated in the CF-5. Personally, I do it the first way, then transfer pretty flat beer to a keg and let it carbonate in the keg once I've connected it to the CO2 tank/regulator I use for carbing/serving.

 

[JAReeves]

I like the idea of cold crashing in primary - I think I’ll try using my camelback bladder from mountain biking, fill it with CO2 and use that for the suckback.

Did this work? I have been looking for a good cold crash-CO2 method that it is affordable and food-safe. One of my buddies saying just put a balloon on it (with all that powder inside) sounded like a really bad idea. Anyone else have suggestions?

 

[VikeMan]

I have been looking for a good cold crash-CO2 method that it is affordable and food-safe. One of my buddies saying just put a balloon on it (with all that powder inside) sounded like a really bad idea.

Anything used as a CO2 reservoir should be cleaned and sanitized first.

 

[Ogilthorpe2]

Did this work? I have been looking for a good cold crash-CO2 method that it is affordable and food-safe. One of my buddies saying just put a balloon on it (with all that powder inside) sounded like a really bad idea. Anyone else have suggestions?

 

[chipmunk]

I haven’t really tried any other methods, but the water bladder worked well for me - I used a 3l bladder - filled with CO2. I crashed a 3gal batch for 2 or 3 days and it looked like it used around 2liters or so. The bladder itself has a wide mouth opening so you can easily clean and sanitize. It also has tubing already installed, so I just popped off the mouth valve and connected it to the stopper.