WY 1968/ WLP002 Bottling Tips

Hey Everyone,

So I've been struggling with bottling any of my beers that use wyeast 1968 (WLP002). Any beer that I put in a bottle will end up overcarbonated. I even keg and bottle off the keg. I know the source of the issue is that the yeast doesn't attenuate the sugars completely and then reattenuates in the bottle.

What I've tried:
Oxygen system: Helped quite a bit. I've found 1968 to love o2 (other sources have confirmed this) The pure o2 increased my attenuation by 1.004sg on back to back recipes.

Rousing(swirl method): no real help.

Rousing (sanitized spoon): So far the most promising. One recipe stopped at 1.020. When roused the 1st time dropped to 1.017. A second rousing dropped it to 1.014.



Things to rule out:
Fermentation Temp: I never let the fermentation temp drop after fermentation has started. Always finish +68F

Pitching Rate: Starters with new packs and 8-16oz harvested yeast pitches.



Some people have issues when bottling this yeast, some don't. Let's get to the bottom of it.

Thanks, Jeff

Things I've been considering trying:

Lowering calcium content of brewing water:
I use Chicago tap water which is medium-hard water. Sometimes I'll add a bit of calcium chloride and gypsum (calcium sulfate). Lowering the calcium content may decrease the insane flocculation of this yeast.

Yeast Nutrient:
Perhaps some yeast nutrient would keep the yeast in suspension longer.

Fermcap S:
This binds to yeast. Maybe it would inhibit some flocculation.

Anyone?

What size starters are you using? Most recipes I see for this strain recommend a 2L, for that reason of stalling out. How long do you primary/secondary for? Any insight into your process might help narrow it down too.

Sounds like your bottling too soon, 1968 typically Will drop early if not treated right.

Pitch cold, allow it to rise to temp and hold until it slows and then allow it to rise more and rouse at the same time until it finishes.

Also be sure of proper pitch rate as with any strain. If you do what I suggest it will finish with good attenuation and provide a crystal clear beer

alane1 said:

What size starters are you using? Most recipes I see for this strain recommend a 2L, for that reason of stalling out. How long do you primary/secondary for? Any insight into your process might help narrow it down too.

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I target a pitch of .75 million cells per milliliter of wort per degree plato. I use Mr.Malty to calculate starter size. I've even gone as far as doing a cell count as well. I've intentionally overpitched and I've underpitched, same results.

I usually make the starter while brewing. I'll cool the wort to ~75F and let it come down to the mid/low 60s over the next 24 hrs. I'll oxygenate the wort and then pitch the whole starter and typically I see lag times of 8-16hrs.

duboman said:

Sounds like your bottling too soon, 1968 typically Will drop early if not treated right.

Pitch cold, allow it to rise to temp and hold until it slows and then allow it to rise more and rouse at the same time until it finishes.

Also be sure of proper pitch rate as with any strain. If you do what I suggest it will finish with good attenuation and provide a crystal clear beer

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I bottle when gravity is stable and always the beer is crystal clear.

I've read about the 64-68-64 Fuller's fermentation schedule. I have never attempted due to fear of cooling fermentation and the yeast dropping out. I typically pitch ~67F Last batch I pitched at 65F. I regularly have fermentation ending 70-73F.

You're confidence is inspiring however, I believe I have the basics of good fermentation covered and am still having issues.

AT-JeffT said:

I target a pitch of .75 million cells per milliliter of wort per degree plato. I use Mr.Malty to calculate starter size. I've even gone as far as doing a cell count as well. I've intentionally overpitched and I've underpitched, same results.



I bottle when gravity is stable and always the beer is crystal clear.

I've read about the 64-68-64 Fuller's fermentation schedule. I have never attempted due to fear of cooling fermentation and the yeast dropping out. I typically pitch ~67F Last batch I pitched at 65F. I regularly have fermentation ending 70-73F.

You're confidence is inspiring however, I believe I have the basics of good fermentation covered and am still having issues.

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I've never had a problem with 1968. I also don't drop temp at all. I pitch cold, like 60 and allow to rise to 65-68 and hold until fermentation slows. Then I simply let it rise and rouse it daily until it finishes. I let it sit at room temp to clear and package \keg. Good luck!

duboman said:

I've never had a problem with 1968. I also don't drop temp at all. I pitch cold, like 60 and allow to rise to 65-68 and hold until fermentation slows. Then I simply let it rise and rouse it daily until it finishes. I let it sit at room temp to clear and package \keg. Good luck!

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What method of rousing do you use? How many times do your rouse?

I use buckets and simply and gently agitate the bucket once daily. Fermentation is typically complete in 7 days, 3-5 days active, a couple days to rouse and finish at ambient, a week to drop bright-clear and then package

I replied a minute ago, but it seemed to have been lost.....anyway, here goes again:

I have seen similar reports on homebrew forums after I experienced the same thing you describe.

I brewed a batch of a Moose Drool clone in 2012, with 1968. It was my only time using that yeast. I have been brewing for 16 years but have never had a batch act like that one. The bottles gushed when opened at room temp. The bottles were not infected nor overcarbed. I know what it's like to open overcarbed bottles, from experience. I suspected the yeast residue was acting like a nucleation site for the carbon dioxide. It is similar to when you add granular sugar to beer, if you've ever done that before.
it was so strange that I contacted wyeast, who confirmed that they have had similar complaints before...

I would add Knox unflavored gelatin at bottling. I think that would bind the yeast residue and cement it to the bottle.

By the way, I still have several bottles of that batch left. Still good! I do refrigerate bottles for two days prior to opening, this helps.

More details are in this post, at hbd: http://hbd.org/discus/messages/52116/51881.html?1351733273

mike_g08 said:

I replied a minute ago, but it seemed to have been lost.....anyway, here goes again:

I brewed a batch of a Moose Drool clone in 2012, with 1968. It was my only time using that yeast. I have been brewing for 16 years but have never had a batch act like that one. The bottles gushed when opened at room temp. The bottles were not infected nor overcarbed. I know what it's like to open overcarbed bottles, from experience. I suspected the yeast residue was acting like a nucleation site for the carbon dioxide. It is similar to when you add granular sugar to beer, if you've ever done that before.
it was so strange that I contacted wyeast, who confirmed that they have had similar complaints before...

I would add Knox unflavored gelatin at bottling. I think that would bind the yeast residue and cement it to the bottle.

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I use gelatin in at kegging time. Nearly no sediment makes it to a bottle. Less than the dusting in the bottom of a Sierra Nevada bottle. I was really hopeful that nucleation was issue, but no luck.

I've noticed that it seems more like the beer doesn't want to hold onto co2; rather than a plain overcarbonation issue. I've also noticed, temperature of the bottles makes a huge difference (not the case with other strains). Freezing cold = just plain overcarbonated. If I just stick a bottle in the fridge for an hr = gushing. I should also mention I get the cidery/ green apple flavor along with the overcarbonation. If I degass the beer, it goes away.

Even wierder, I've noticed the gushing when warm issue disappears after ~1 year in the bottle. I have some barlewine that gushed terribly and I basically forgot about it. I cracked been opening one or two for the past few months and had no issues. I wonder if the co2 finally hydrated to carbonic acid, or the excess co2 escaped slowly thorough the cap liner. Another mystery to add to the list.

I have also had similar issues with 1968 yeast and bottling. I love the flavors of it and how it drops clear in a few days but I have the same issues as many other have when bottling it. Here are some of my test results:

A Tale of Two British Yeast

I have others tell me "it must be an infection" but when I was making my test batches of British Milds, I knew in the past I had problems with bottling 1968 so I was extra careful with sanitation on these batches. It seems 1968 (and some other British yeasts) drops out a little early (stirring is necessary) and I do suspect it will continue to chew on more complex sugars slowly in the bottle. I have never had this problem with US05, Wy1056, Wy1010, etc. I have never had a gusher with any other yeast. I love this yeast but I plan on trying other British yeast this winter and I am a little hesitant in using it again.

Tony

Blueflint said:

I have also had similar issues with 1968 yeast and bottling. I love the flavors of it and how it drops clear in a few days but I have the same issues as many other have when bottling it. Here are some of my test results:

A Tale of Two British Yeast

I have others tell me "it must be an infection" but when I was making my test batches of British Milds, I knew in the past I had problems with bottling 1968 so I was extra careful with sanitation on these batches. It seems 1968 (and some other British yeasts) drops out a little early (stirring is necessary) and I do suspect it will continue to chew on more complex sugars slowly in the bottle. I have never had this problem with US05, Wy1056, Wy1010, etc. I have never had a gusher with any other yeast. I love this yeast but I plan on trying other British yeast this winter and I am a little hesitant in using it again.

Tony

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Thanks for the link. Yeah, I don't buy the "It has to be an infection." I used to worry about that but now I'm convinced its not.

1) A degassed sample doesn't exhibit the tartness or apple flavors. Acid (tartness) won't disappear when degassed. If it were an infection those off flavors would be retained.

2) It doesn't ever happen with other yeast strains

3) No yeast strain can be "prone to infection" If the initial culture was pure, it's not going to magnetically attract microbes.

4) I've learned from making sours (not on my equipment) that it is much more difficult to infect beer than one would think.

I spoke with a brewer at Wyeast about the issues I am having.

What we discussed:

• 1968 Does indeed have a high o2 requirement.
• Do a forced ferment test with pitched wort (from the fermenter). A gross overpitch (which I was doing previously) isn't as informative as a sample of your actual pitch rate.
• A 2nd round of oxygen 12-18hrs after pitching might be a good thing. Even on small beers this might be a good idea. I think that the o2 may be dissipating out of the wort before the glob of 1968 has a chance to suspend itself.

I made an Ordinary Bitter to implement these process changes.

I pitched the yeast before oxygenating. Swirled the fermenter and oxygenated. 8hrs later, I oxygenated again. Everytime I walk past the fermenter I give it a swirl(I'm re-examing the swirl rousing technique). I roused the fermenter at least 3x daily. Even more so I swirl the forced ferment test. With the forced ferment test I see exactly how quick the yeast is to flocculate. In the 22oz bomber I'm using for it, I see the yeast suspended for only a few hours. I take this as a sign that near constant rousing is necessary.

As of today. The forced test showed a gravity reading of 1.011. The fermenter is at 1.012. I gave the fermenter another swirl and we'll see where it goes.

Even if this test is a failure, I still have a few more few more tests in me before I give up on this yeast. I'll certainly do daily gravity tests on the next one. I wish I did them on this batch.

How did the test go?

mike_g08 said:

How did the test go?

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I'll open a bottle later today and take a gravity and check carbonation then compare it to a sample from the keg.

Opened a bottle today. No cidery or tart off flavors!

I tested the gravity of the bottle 1.010. There seems to be a slight increase in carbonation (as the 1.002 point drop in gravity would suggest). The beer was carbonated to about 1.5vols in the keg. So the beer has plenty of room to carbonate further without being undrinkable. I'm not using this as a solution to the issue but It just happens to be the case.

An interesting thing is that I took a gravity of the ordinary bitter in the keg and it was at 1.008. The keg has sat at 57F while the bottles have been sitting at 70F. I guess this would suggest that very little yeast is making it into the bottle.

While the numbers suggest the issue of further attenuation is still prevalent, none of the problems caused by the attenuation are apparent. I will keep an eye on the beer in the future and see if the gushing and off flavors appear. I'm pleased that I have drinkable bottled beer but will continue to look into a solution to the continued attenuation.

I have a Scottish Ale fermented with 1968 that is near terminal currently. I've taken daily gravity readings and will report my findings on that.

Test number 2 with the scottish ale went well. It's done fermenting as of today. I took daily gravities on this one. Here's how the fermentation went.

Day 1: Pitch, swirl fermenter to break up yeast, then oxygenate 2min. 12hrs later oxygenate again 1min Original Gravity: 1.048
Day 3: 1.025
Day 4: 1.016
Day 5: 1.016, Rouse with sanitized spoon
Day 6: 1.016
*Note: everyday the fermenter was swirled at least 3 times.

I noticed a lot of airlock activity after rousing with the spoon. According to the gravity, there was no additional fermentation, however. I know from harvesting 1968 from conicals that it retains lots of co2, this could explain the airlock activity.

The fact that the gravity has not dropped after using the spoon rousing method, seems to indicate that yeast has attenuated fully through only the use of fermenter swirling (or perhaps that isn't even nescessary). This is excellent, I would really like to move away from the spoon swirling method due to the increased oxygen pick up and contamination risk.

I'll be kegging this beer sometime in the next couple days. I'll carbonate it to 2.0 volumes and bottle a few to open over the next couple months and watch for off flavors. We have a Zahm 7000 Bottle piercer at work, I'll bring a few in and measure co2 volumes after bottling and a month or so down the line.

great work here. i've had trouble with 1968 attenuating in the past but love the strain.

i like to use it on APA/IPA's and prefer these beers as dry as possible. I'll give the 02 blast after 8-10hrs a try and maybe roust on day 4 or so.



I have a small (1.045) pale ale fermenting with 002 right now - first time using this strain as I normally grab 1968 (cheaper at my LHBS)

just to share/contribute to the discussion a little..

I brewed a pale ale 6 days ago. It came in at 1.045 so it was a pretty small beer. I mashed @ 149*

Day 1: pitched WLP002 @ 62*, pure 02 for 90 seconds.
Day 3: raised temp to 64
Day 4: raised temp to 68 as fermentation had greatly slowed (read: airlock activity)
Day 5: Airlock activity was basically stopped. Sample read 1.013 for ~ 71% AA. Hydromemeter sample was clear as a bell. Swirled yeast per reccs here
Day 6: Moderate airlock activity and sample read 1.008 for 82% attenuation. Sample appeared fairly cloudy.

Rousing this yeast appears to really have kicked up fermentation again

jammin said:

just to share/contribute to the discussion a little..
Day 5: Airlock activity was basically stopped. Sample read 1.013 for ~ 71% AA. Hydromemeter sample was clear as a bell. Swirled yeast per reccs here
Day 6: Moderate airlock activity and sample read 1.008 for 82% attenuation. Sample appeared fairly cloudy.

Rousing this yeast appears to really have kicked up fermentation again

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Jammin, thanks for sharing your results thus far. Please follow up with how it turns out in the bottle. 1.013 to 1.008 is a significant drop; glad it happened in the fermenter and not the bottle. Hope this solves any bottling issues you may encounter.

As I commented on the last page, I LOVE 1968 but also have been frustrated with it. I also like using 1469 and also to a lesser extent had problems with it. I hate the green apple or cidery flavor when bottling 1968 and the over carbing. I have also found rousing/stirring and added o2 helps.

It does appear that British yeasts need higher oxygen levels during their primary growth phase, this along with them being very flocculent is creating the problems. These yeasts are originally from breweries that either have some sort of pump over or recirculating to keep the yeast in suspension along with adding small amounts of o2.

You guys are on the same trail I am. I will be using 1968 in a couple brews coming up, ones I have made several times so I know what to look for.

I am currently making some bitters with 1318 and at the 36 hour mark, pulled the lid and stirred like mad (I make wine so am use to this sort of thing). I saw a big increase in activity about 1 hour after doing this. 1318 is a little slower to drop clear than 1469 and 1968 but still does quite nicely and cakes to the bottom of the bottle real well. So far I really like the flavors it has, even used it on some non British ales, really like it in a basic Amber Ale. In fact, I like 1318 more than 1469 and about equal to 1968...almost.

Tony

Are these strains used to an open primary, perhaps?

There is some speculation these prefer either no cover or low top pressure (loose cover on bucket) to preform best but that may be more of an o2 issue than anything. I am experimenting on the 36 hour stir and o2 addition. I find most of my British style beers are completed in 72 to 96 hours when fermented between 64-68 degrees so I don't want any o2 added much later than the 36 hour mark. The flavors these British yeasts have are fantastic and it is just a matter of figuring what they prefer in our home environment vs. their original breweries.

Tony

Blueflint said:

There is some speculation these prefer either no cover or low top pressure (loose cover on bucket) to preform best but that may be more of an o2 issue than anything. I am experimenting on the 36 hour stir and o2 addition. I find most of my British style beers are completed in 72 to 96 hours when fermented between 64-68 degrees so I don't want any o2 added much later than the 36 hour mark. The flavors these British yeasts have are fantastic and it is just a matter of figuring what they prefer in our home environment vs. their original breweries.

Tony

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Any luck with the 36hr o2?

Still working on this. The scottish ale exhibited symptoms at 2 months in the bottle. This is a significant increase in shelf life, but still unacceptable. I never measured the bottled co2 volumes but the gushing (at room temp) was enough to let me know it had increased.

I will have access to a very exciting new toy shortly. A dissolved oxygen meter capable of reading as low as 4ppb. . I'm excited to use this to measure wort oxygenation. Also, I'm very interested to see how much DO is picked up by rousing via the spoon method.

I'll probably get another batch in before the DO meter comes. I plan on trying some yeast energizer in that one.

I had an IPA in the fermenter I thought I would try yeast energizer on.

fermentation stopped at 1.016
Roused with spoon 1.014
~2.5tsp yeast energizer in boiled water yielded 1.010

Might be on to something here. I'll bottle some once its bright and carbonated. I'll report back in 2 months, ha.

Interesting. Hope it works.

Still at it.

Bad news on the dissolved oxygen meter. I've been using it at work nearly everyday but it takes about a gallon or so to get an accurate reading.

I'm thinking the yeast nutrient thing may be promising. I make starter with the end of runnings. I know the later runnings have less nutrients than first runnings. Not sure it the last runnings are nutrient deficient enough to stress the yeast. I notice Duboman claimed not to have the issue and his recipe included yeast nutrient.

I have never in all my years of homebrewing used yeast nutrient. I've always read that all malt beers should have all the required nutrients (except zinc). So I put some in the boil of the ESB. We'll see if that works.

Just to rule out infected wort I did a forced wort test post chill. Its been 4 days and still is showing no signs of fermentation.

The answers to all your british yeast questions are contained in this thread: https://www.homebrewtalk.com/showthread.php?t=221817

...spoiler alert: wy1968 is a tough one to bottle condition with.

I don't remember if its actually from the thread or my own personal experience but 1318 london 3 isn't the best tasting but it is pretty good and the easiest to use. Its not the amazing malt bomb that is 1469 or 1968 but it wont floc out on you and then restart in your bottles, it wont **** out a ton of diacetyl, it won't turn to cidery rocket fuel when you repitch. It just works and makes pretty decent english beer.

gbx said:

The answers to all your british yeast questions are contained in this thread: https://www.homebrewtalk.com/showthread.php?t=221817

...spoiler alert: wy1968 is a tough one to bottle condition with.

I don't remember if its actually from the thread or my own personal experience but 1318 london 3 isn't the best tasting but it is pretty good and the easiest to use. Its not the amazing malt bomb that is 1469 or 1968 but it wont floc out on you and then restart in your bottles, it wont **** out a ton of diacetyl, it won't turn to cidery rocket fuel when you repitch.

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Hey GBX,

Yeah, I've read through all the pages in that thread. Nobody seems to have a definitive answer as to how to solve the issue. Some users have the issue, some don't. I want to figure out why and solve it once and for all.

I'm very familiar with 1318. It's 1968 or bust for me.

What have your personal experiences been with 1968?

Honestly, I've been using WLP002 for over a year now as my house yeast because I've been on a bitter and mild kick. I've only had drastic over-carbonation once and other than that have not had a problem bottle conditioning, as I never keg.

As another member said, try an "open" or loose-top primary. Are starters being used? What temp are we doing the primary at? What temp are we bottle conditioning at? How many volumes of c02 are we shooting for when we bottle condition? Are we estimating volume of beer we're carbonating accurately?

I only ask because my fairly low gravity bitters and milds have been turning out great with 10 days of primary around 65-68F and 10-14 in the bottle near 70. It just seems like people are working too hard and over-complicating things to me, but perhaps I'm missing something.

Anyhow, I hope we all figure it out!

lowtones84 said:

Honestly, I've been using WLP002 for over a year now as my house yeast because I've been on a bitter and mild kick. I've only had drastic over-carbonation once and other than that have not had a problem bottle conditioning, as I never keg.

As another member said, try an "open" or loose-top primary. Are starters being used? What temp are we doing the primary at? What temp are we bottle conditioning at? How many volumes of c02 are we shooting for when we bottle condition? Are we estimating volume of beer we're carbonating accurately?

I only ask because my fairly low gravity bitters and milds have been turning out great with 10 days of primary around 65-68F and 10-14 in the bottle near 70. It just seems like people are working too hard and over-complicating things to me, but perhaps I'm missing something.

Anyhow, I hope we all figure it out!

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I can't speak on the bottle conditioning part, but my beers that are kegged and then bottled form the keg still exhibit the continued attenuation. I do use starters. I've tried overpitching as well as underpitching.

Do you use yeast nutrient by chance?

I do not, no. My methods are incredibly basic. Honestly my advice would be to look at a simpler solution. Rousing the yeast (gently) once a day in the first 2-3 days or so is a good idea even by white labs' advice. Also perhaps just shoot for slightly lower volumes of c02 on your next batch using the yeast. Even .2 volumes can certainly make a difference.

lowtones84 said:

I do not, no. My methods are incredibly basic. Honestly my advice would be to look at a simpler solution. Rousing the yeast (gently) once a day in the first 2-3 days or so is a good idea even by white labs' advice. Also perhaps just shoot for slightly lower volumes of c02 on your next batch using the yeast. Even .2 volumes can certainly make a difference.

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Yeah, I rouse daily. I've certainly found that anything over 2.5vols does not suit this yeast. Maybe 2.5vols would be fine once it's stable. In either case, I do prefer around 1.5-2.0 volumes.

If you have the time, please look over the thread from post #1. I would love a simple solution to this, hopefully you could pinpoint what you do differently in your process than those of us with the issue.

AT-JeffT said:

Hey GBX,

Yeah, I've read through all the pages in that thread. Nobody seems to have a definitive answer as to how to solve the issue. Some users have the issue, some don't. I want to figure out why and solve it once and for all.

I'm very familiar with 1318. It's 1968 or bust for me.

What have your personal experiences been with 1968?

Click to expand...

I used 1968 for about 20 batches and had similar results. I couldn't get a beer that was malty that didn't have a ton of diacetyl. I did have some success bottle conditioning if I left it in the primary for upwards of 2 weeks but the resultant beer was very very clean and all the Englishness was gone. The last beer I did with it was a 1.070 old ale that I keg conditioned for 6months before bottling. It was really good for the first year in the bottle but then it started to overcarb and get thin. Maybe its an infection but its very typical 1968. The best results I had were in low gravity bitters and milds that I overpitched (ie more than a pint of thick slurry into 5gal) and fermented cool (starting at 62F) and kegged, crash cooled and fined within a week. There was still a perceivable amount of diacetyl but awesome malt and fruit was still there.

AT-JeffT said:

Yeah, I rouse daily. I've certainly found that anything over 2.5vols does not suit this yeast. Maybe 2.5vols would be fine once it's stable. In either case, I do prefer around 1.5-2.0 volumes.

If you have the time, please look over the thread from post #1. I would love a simple solution to this, hopefully you could pinpoint what you do differently in your process than those of us with the issue.

Click to expand...

I did read through the whole thread before posting because I'm interested in the topic. Some differences are that I use WLP002. I know that they're supposedly the same strain, but even the "same strain" from different companies can exhibit different behavior.

I also make pretty low gravity beers usually, like around 1.045 OG. I almost always use a loose-top or open ferment for at least the first 3-4 days. I also pretty much never shoot for more than 1.5 volumes, or not much more. 2.5 is probably pushing it. If you're making English styles with it, many have low levels of carbonation anyhow.

A shorter primary might also help. Although I make mostly low gravity beers, I pretty much never let it go past 9-10 days, and have done 7 before with no issues. It's always done between 3-5 days for me anyhow, so not giving it extra time to sit around and flocc out hard like it does would see to be good advice to me.

Like I said, I hope everyone figures it out for their personal system and uses! I'm not an expert by any means, just detailing my process that seems to work.

I brewed 10gal of an American wheat and split it with 1056 and 1968. The 1056 FG was 1.010 and the 1969 FG was 1.012. Started @60F and slowly raised. Both are kegged and the 1968 hasnt carbed up anymore than what it was initially.

Big news Everyone,

A very possible break through. I believe the source of the overcarbonation in my bottles is due to my lack of dedicated beer lines. My standard procedure(until this discovery) was to move my single beer line from keg to keg to serve all the beers I have in kegs. Typically I have at least 2 beers available at a time, usually 1 beer with 1968 and one with some other yeast. I was constantly swapping the line between kegs.

I also bottle off the kegs with a Biermuncher beer gun (See: here) When swapping lines back an forth I imagine a few yeast cells would cling to the walls of my serving line. Later, when bottling a few of those yeast cells would make it into my bottles. Since 1968 the least attenuative yeast I ever use, any other yeast would attenuate those sugars not consumed by 1968.

So, it would seem another problem is solved by cleaning and sanitation...shocking. I now have a dedicated bottling line and a dedicated floating line.

Testing the theory:
I bottled one beer with the non-dedicated line and bottled one beer with the freshly cleaned and sanitized dedicated line. I waited a few weeks (3, I think) and opened both. The results were in line with my theory. The non-dedicated line bottle over carbonated and the dedicated line was right on.

I degassed and checked the FG of both. The non-dedicated bottle had dropped a few points, while the dedicated one was the same FG as I recorded when kegging it. This is a first!

So it would seem that this is just a matter of true cross-contamination. If you are using your beer serving line as a bottling line, treat it accordingly.

I hope those who have also been having issues with 1968 will find this solves their issues as well. What I would like to know now, is if this could be the possible cause of your issues. Please let me know.

On a personal note; It may be quite a while before I can post another definitive test.

I would like to do another bottle test to be sure. I would like to give the bottles longer and bottle more than one to be sure.

Sadly, I find my motivation to homebrew waning. We've expanded our fermentation capacity at work and we are brewing about twice as much. This leaves me pretty unmotivated to homebrew.

I will hope to do another test, but hold tight. I am very, very eager to hear if this solves others problems. Please do your own experiments and let us know the results.