Help: Why do I occassionally have zero head on kegged beers?

[macaronijones]

I'm having a weird problem with two of the beers I've recently kegged. After burst carbonating for a couple days they seem to pour fine, nice head, nicely carbonated, I'm happy! Then they sit till the next weekend and suddenly start pouring with ZERO head, or there's a millimeter and it dissipates quickly and doesn't come back even with swirling. Thing is, the carbonation still feels right in the beer itself, and this lasts the full length of the keg (a month or so) until it's kicked.

More info:
-probably irrelevant but interestingly both beers have been very dark, a robust porter and an oatmeal stout. well-regarded recipes that should not have a head retention issue. It's like i'm drinking pepsi.
-It's not an issue with my glasses, i clean without soap and the keg right next to it pours w/ beautiful and lacing head in the same glass.
-my system is set at about 40° and 12 psi
-carbonated both by rolling for 2 minutes @ about 30 psi, leaving for the rest of the day at 30 psi, then purging and setting to serving pressure.
-i understand the variabilities of the above method, but what's confusing is the head going from perfect to poor and never recovering. Also most of my other beers carb fine with this method, or if they are over/under i can then successfully adjust it back.
-i use perlick 650's now but the first time this happened was with picnic taps.
-i dont thick it's a leak because i've used the same 5lb tank on five kegs now and still haven't hit the red line on the regulator
-I use two different kegs, and the first time this happened was long enough ago that i'm unsure if it was the same keg in which it's happening now.

pretty much makes me not want to drink the beer... help!

 

[Homercidal]

All i can say is that if the carbonation feels right in the glass, and it's still not producing head, there is something wrong with the glass, or with the brewing method.

Carbonation means the bubbles are forming, so it seems either there isn't enough proteins left in the beer to produce a lasting bubble, or something is causing the bubbles to burst before they can form.

Some beers aren't known for having much lasting head, but the beers you mention are certainly quite capable of producing a quality head, historically. (Although I've had some porters that didn't have much head and did kind of resemble pepsi in the glass.)

 

[macaronijones]

All i can say is that if the carbonation feels right in the glass, and it's still not producing head, there is something wrong with the glass, or with the brewing method.

Carbonation means the bubbles are forming, so it seems either there isn't enough proteins left in the beer to produce a lasting bubble, or something is causing the bubbles to burst before they can form.

Some beers aren't known for having much lasting head, but the beers you mention are certainly quite capable of producing a quality head, historically. (Although I've had some porters that didn't have much head and did kind of resemble pepsi in the glass.)

Yeah this happened with EdWort's Robust Porter and Yooper's Oatmeal Stout, both beers that should have plenty of head-retaining properties. The confusing thing is that the beers were basically exactly how I wanted them head-wise, and then declined. I could be wrong that the carbonation itself is currently fine, and in fact it's undercarbed, but it's certainly not flat and porters shouldn't be super fizzy anyways...

I've read here and there that the shaking to force-carb method can "use up" enough of the head forming proteins such that head formation/retention can suffer, but it seemed like sort of a suspect theory to me.

When rapid force-carbing, is it normal for a beer to initially seem well-carbed and then sort of regress until eventually evening out...? Still wouldn't explain why the last one sat for a month and never regained any head, just trying to think of everything.

 

[day_trippr]

If you're not holding the beer at a combination of temperature and CO2 pressure to maintain the desired carbonation level it could easily flatten as the beer is consumed and the head space increases.

Otoh, if you set the CO2 pressure vs dispensing temperature using our favorite carbonation table the carbonation should reach and hold at whatever level you selected until the keg empties. Under those guidelines, if anything the carbonation will improve over time, burst-carbed or not...

Cheers!

 

[55x11]

If you're not holding the beer at a combination of temperature and CO2 pressure to maintain the desired carbonation level it could easily flatten as the beer is consumed and the head space increases.

Otoh, if you set the CO2 pressure vs dispensing temperature using our favorite carbonation table the carbonation should reach and hold at whatever level you selected until the keg empties. Under those guidelines, if anything the carbonation will improve over time, burst-carbed or not...

Cheers!

Agreed. If you CO2 pressure and temperature are corresponding to 2.5 or more volumes of CO2, there should be a sizeable head. It may disappear quickly, which may mean you have some fatty substance (dirty glass, etc.), but there should be precipitation of CO2 as you pour.

 

[macaronijones]

View attachment ImageUploadedByHome Brew1470697275.232964.jpg
This is both beers I have kegged right now, the porter I'm having the issue with obviously on the right. The left is a pale I burst carbed four days ago. Both were poured right down the middle at the same flow control setting, and here they other about 15 seconds later. They're connected to the same regulator with a "Y" split, (could it have something to do with that??) set to 12 psi at about 40 degrees.

The porter's actually getting worse, this time there wasn't even a hint of a head as it poured. But last weekend, it looked like the beer on the left.

Wtf?!?

 

[Stillraining]

FWIW..lots of porters/stouts I have had from pubs have little to no head as well. I think the higher Love-bond grains have oils from the roasting process that tend to kill head. Some of mine are definitely better then others. The ones with the black malts always have the least head. Or at least the quickest diminishing one.

 

[PapaO]

It sounds like you don't have the gas on. Is there pressure in the porter keg?

 

[macaronijones]

yes... the gas is on and there is pressure. if i pull the pressure release i can hear it fill back up. both kegs connected to same C02 bottle, same regulator, same psi, etc.

And i agree that porters/stouts may have less carbonation or head but this is not even close to appropriate (but it was last weekend, lol)

 

[macaronijones]

It seems like both times this has happened the beer/head was fine when it was the only tapped keg in my kegerator, but then when i added a second keg and hooked it up to the same regulator via the WYE splitter, that's when beer #1 started to go flat/lose head. Wondering if it could be an issue with that splitter, applying more pressure to one keg preferentially while the other suffers?

Thanks all for the responses.

 

[macaronijones]

Or, is it possible to have a leak that's slow enough to not materially affect my C02 tank level but fast enough to cause this problem in two beers?

 

[55x11]

Or, is it possible to have a leak that's slow enough to not materially affect my C02 tank level but fast enough to cause this problem in two beers?

Or the Y is leaking at the connection? Or maybe leaky keg (but you seem to have ruled this out).

Does carbonation recover when you connect only one keg?
Do you force-carb with higher pressure and then switch to lower pressure? Do you shake? describe your process a bit.
When you pull the pressure release (or press on gas in poppet) on the keg, does the CO2 come out forcefully?

Are the two beers at the same temperature? Is it possible that the stout is much warmer?

You could try disconnecting the CO2 for a few hours, and see if the pressure drops. Or close the valve on the CO2 tank, and disconnect the second keg gas line in and see if pressure drops over time (but keep the Y connected).

(The reason many darker beers - stouts etc. are less carbonated on purpose, maybe to 1.5-2 volumes - is because they are carbed to less volume, on purpose. This is in part because of tradition of cask beers in England where a lot stouts originate and perhaps in part because they are served at warmer temperatures and two much carbonation conflicts with the rich malty taste. Summer, lighter beers like Hefeweizen, or Berliner Weisser will be carbed to higher degree, 3 volumes and sometimes even higher).

 

[macaronijones]

Today's goal after work will be to rule out any leaks... Although it really seems like it would have drained my c02 tank by now, five kegs in and two potentially with leaks.

Yes both beers are at the same temp and both have c02 rushing out when I pull the PRV. I describe my carbonation process in my first post.

 

[Homercidal]

Leaks aren't the cause. If you are connecting gas via a Y adapter, then you have an open system where the gas is free to travel in any direction without limitation. Anything beyond the regulator or a check valve will be balanced through the whole system; lines, kegs, etc.

Any drop of pressure in any location will cause pressure to drop through the whole system.

A leak, barring catastrophic, will not cause a noticeable drop in pressure. Rather you would have a small continual flow of gas through the leak, but at that same pressure.

 

[macaronijones]

Leaks aren't the cause. If you are connecting gas via a Y adapter, then you have an open system where the gas is free to travel in any direction without limitation. Anything beyond the regulator or a check valve will be balanced through the whole system; lines, kegs, etc.

Any drop of pressure in any location will cause pressure to drop through the whole system.

A leak, barring catastrophic, will not cause a noticeable drop in pressure. Rather you would have a small continual flow of gas through the leak, but at that same pressure.

So what you're saying is that a small leak will allow C02 to escape but will be continually replaced by more C02, therefore causing no noticeable change in the pressure of the keg or the system as a whole. That makes sense.

That being said, I just opened the kegerator and pulled out the suspect keg. I put my ear close to the gas QD and heard a noticeable hiss. I pulled the QD off and it continued to hiss for about five seconds before stopping. I put it back on as firmly as I could and made sure I couldn't hear any hiss, and stuck it back in the fridge.

Now that I think about it, last night when i poured those two beers in the picture above not only did the porter come out without any hint of head, it also came out a bit slower.

I'm just having a hard time reconciling the fact that I have an apparent leak at my gas QD along with a flat-ish, headless beer and that one is not the cause of the other.

 

[ryan810cows]

Please let us know if the leak turns out to be the problem. I'd love another side-by-side picture!

 

[KartRacer54]

I am having a similar problem with a dry stout. I have blamed the problem on #1 the recipe
#2 the mash temp which I now know was in the upper range.
Am patiently waiting for info to make sure I don't have this again.

 

[LBussy]

Is it possible that you have not purged the kegs properly? Possible maybe that what you perceive as "ok" carbonation in the beer is actually low? If you have air mixed in there you will have a lower effective CO2 pressure and you will gradually be losing carbonation.

One way to test is to burst carb again and see if the head comes back. If it does, you are losing carbonation somehow. Like you said, if you had a leak that tank would be gone by now so mixed gasses in the headspace are my bet.

It takes a surprising number of purges to get O2 levels down to a desirable level for long term storage (you could settle for more O2/less purges if you are going to consume the beer faster). @ 30 PSI it takes 15 cycles to get O2 down to 0.01%. Here is a chart that someone (and I wish I remember who sent it to me) shared.

 

[KartRacer54]

Lee
Great info. I have totally botched this process. 2or3 medium burst and I have called it good.
Thanks

 

[macaronijones]

I purged 5 or 6 times at about 30 psi, so it's possible i underpurged and in the future i'll use more. However, this is the same process I've used for all of my kegged beers, and i've only had this problem on two as described.

I THINK i've figured out the issue... As i said above, i heard a leak from the gas QD on the right side of my "Y" split. I tried putting this QD on the other keg, and heard the same leak, meaning it's specific to that QD and not the keg. I took the QD from the left side and hooked it up to the porter, no leak. I've now had it on there for a couple days and carbonation is returning, almost normal again. The two times this has happened have been two of the only times i've had two kegs in the kegerator, so using both QD's, so that makes sense. Why my C02 keg isn't drained, I don't know. Why it isn't still balanced despite the small leak, I also don't know. But it seems like too much of a coincidence to ignore. I emailed keg connection to replace that QD.

I'll post another side by side picture when i get home later.

 

[LBussy]

Here's hoping it's simple. Like you said it doesn't answer all the questions, but the end goal is well-conditioned beer. So, if you get that, all the rest is academic.

 

[macaronijones]

View attachment ImageUploadedByHome Brew1470947171.364811.jpg

Here it is now after several days being on the "good" gas quick disconnect.

 

[LBussy]

Well that's just strange, but I'm glad you have it settled!

 

[Homercidal]

Awesome! Maybe my logic isn't as sound as I thought. Something to ponder over a beer at the campsite tonight. (It it's not raining then...)

 

[Stillraining]

Awesome! Maybe my logic isn't as sound as I thought.

Nor mine either.

 

[Stillraining]

Here is a chart that someone (and I wish I remember who sent it to me) shared.

My guess would be Doug..I think the first chart is his creation.

 

[LBussy]

My guess would be Doug..I think the first chart is his creation.

Bingo!

Both are from him .... the spreadsheet is the data behind the chart.

 

[doug293cz]

Is it possible that you have not purged the kegs properly? Possible maybe that what you perceive as "ok" carbonation in the beer is actually low? If you have air mixed in there you will have a lower effective CO2 pressure and you will gradually be losing carbonation.

One way to test is to burst carb again and see if the head comes back. If it does, you are losing carbonation somehow. Like you said, if you had a leak that tank would be gone by now so mixed gasses in the headspace are my bet.

It takes a surprising number of purges to get O2 levels down to a desirable level for long term storage (you could settle for more O2/less purges if you are going to consume the beer faster). @ 30 PSI it takes 15 cycles to get O2 down to 0.01%. Here is a chart that someone (and I wish I remember who sent it to me) shared.

My guess would be Doug..I think the first chart is his creation.

Bingo!

Both are from him .... the spreadsheet is the data behind the chart.

Yep, they are my chart and table. Although @LBussy added the nice color coding to the lower right corner of the table, after I sent him the spreadsheet. The originals have been posted multiple times on HBT.

I purged 5 or 6 times at about 30 psi, so it's possible i underpurged and in the future i'll use more. However, this is the same process I've used for all of my kegged beers, and i've only had this problem on two as described.

...

Five purges @ 30 psi is plenty for the pressure in the keg to be entirely due to CO2. So, no carbonation issues could result. It's just not enough purges to get low enough O2 for good storage life.

Brew on

 

[macaronijones]

thanks yall. right now i'm just moving the "good" quick disconnect from one keg to another depending on what i want a taste of, inconvenient but effective. Per keg connection a replacement is on the way.

 

[doug293cz]

Is it possible the "bad" QD has a defective or broken poppet pin? In that case the QD might not be able to push the keg poppet open so that CO2 can enter the keg. That's the only explanation that makes sense to me. It the keg has the correct pressure inside it, you will get carbonation. You can't cheat physics. In order for a leak to lower the pressure enough to prevent carbonation, the leak flow rate has to be fast enough to empty your CO2 cylinder in a few hours or less.

Can you take the bad QD apart and post a pic of the poppet here?

Brew on

 

[macaronijones]

I will later this weekend. To be clear, carbonation wasn't prevented, it occurred at high psi (30) and then was lost over the course of a week after it was dropped to serving pressure (12). I've never taken apart a QD or gas post so not familiar with the components, but after playing with the QD and listening to the leak it seems like the poppet didn't "seat" perfectly or whatever and allowed gas to slowly escape from the keg, while somehow not simultaneously draining the C02 tank. Honestly I can't quite decide how that makes sense, but I can't argue with the results.