Spontaneously Resumed Fermentation with M47 Belgian Abbey Yeast?

[Protos]

I've been using Mangrove Jack's M47 Belgian Abbey yeast for years. Usually I kept it in primary for 3 weeks and fermented mostly at 20 to 22C. This time however I decided to push the temperature to the high limit of its range at 24C.

Now I see a strange thing. At the day 20, the yeast (almost fully flocculated at the monent) suddenly resumed fermentation. Micro-Kraeusen, bubbles, yeasty haze, all familiar signs, again. The "secondary fermentation" in the primary vessel goes on already for another week. A new large layer of yeast is growing on the bottom.

I'm pretty sure the fermenter is clean: I nuked it (as I nuke everything in Summer) with 0.05% industrial grade Peracetic Acid.
Of course, the easiest way would be just to open the fermenter and check gravity and smell. However, because of the plenty of airborne bugs in the summer air (I've been losing beers to it previously) I try to avoid opening the carboy as much as I can. What if it's not really infected?

So my question is rather theoretical: has anyone experienced a resumed fermentation with M47 (or WLP570/WY1388 believed to be close to it)?
In my experience, resumed fermentation is quite a common occurence with M21 Belgian Wit (I've had it twice with it) without any apparent infection, but with M47 that looks very new to me.

 

[HM-2]

I've used M47 a couple of times and found it has an affinity for high temperatures. I get a much drier ferment out of it at circa 26c than I do down in the 18-20 space. That said, I've not seen it stop fermenting for a week plus then restart. Have you roused it or anything? Added a dry hop? Any kind of interaction that might set things in motion again?

 

[Protos]

No interaction at all. No temperature swings as well, stable 24C all way long.
It doesn't look like an infection either: I have had various infections in my 240 batches over time, none of them stroke as late as after full three weeks when the fermentation had actually finished.

The only explanation I could think of is that some Mangrove Jack yeasts are actually blends of two or more strains, so M47 might be too I guess, a blend of yeasts with different fermentation timeframe? I hope someone knows more.

 

[dmtaylor]

Hmm. I have seen stalled-then-renewed fermentations with certain Belgian yeasts in the past, particularly WLP530/3787, but I know WLP400/3944 are very closely related to 530/3787. It is entirely possible that M47 is not actually equivalent to WLP570/1388 but is more closely related to the others listed above. We don't actually have genomic data for Mangrove Jack yeasts so these are guesses. It is also entirely possible that M47 and/or WLP570/1388 are similarly fussy yeasts, being that they are Belgian and being that many Belgian yeasts do weird stuff like this. I have not used WLP570/1388 enough times to recall how it behaves, and never touched M47 (yet).

So much data to ponder....

 

[Protos]

I have seen stalled-then-renewed fermentations with certain Belgian yeasts in the past

That's what I was hoping to hear
M47 is my "House-Yeast" for sweet chewy strongish Belgian Blondes which I like alot and brew regularly.
This is my twelvth batch with it, and I thought I knew this yeast well.
Will wait till this resumed fermentation is over, then open the carboy, try and bottle if it's good. If it doesn't throw the third spontaneous refermentation after another week.

 

[mashpaddled]

The Duvel strain is known for stalling out and taking a while to finish fermentation

 

[Protos]

Bottling day.
Sample taken, measured and tasted. 93% attenuation (for M47, norm is 80%). Seems to be a Diastaticus infection. Or rather a wild yeast infection, as I haven't been using Diastaticus yeasts for a year.
No apparent off-flavours, still down the gurgler it goes. Because I hate to "drink up" flawed batches of strong beers.

 

[Miraculix]

Bottling day.
Sample taken, measured and tasted. 93% attenuation (for M47, norm is 80%). Seems to be a Diastaticus infection. Or rather a wild yeast infection, as I haven't been using Diastaticus yeasts for a year.
No apparent off-flavours, still down the gurgler it goes. Because I hate to "drink up" flawed batches of strong beers.

I don't get it. If it tastes good, where is the flaw?!

 

[Protos]

Well, it doesn't taste GOOD. It just doesn't taste as bad as it could have, provided it's somehow got an infection. The aim wasn't to make a relatively passable beer, it was a recipe I've brewed several times which must have a certain flavour profile which I know well and which I missed this time.

 

[GoodTruble]

Hey, bad beers just become shandys, especially in the summer time. Just find a juice it mixes well with.

 

[Protos]

Nice idea!

 

[Protos]

It seems I'm having the same problem again, using yeast from the same resealed package. Obviously, it's the yeast (rather than fermenter or bottling bucket, which I suspected) that has been somehow contaminated.
Again, at the third week in primary the yeast has suddenly resurrected despite the cool ambient temperature and now I know where it's going to.
The batch I was talking about above came out not as bad as to dump it, still not something to be proud of either. I will have to gradually drink it up and I hate the idea to get another 8% alc. substandard batch of similar kind.

What's your opinion, if adding Campden might help to stop the wild fermentation before the gravity drops too low?
To hell with carbonation, I need to save my nice and pretty Blond before the contaminated yeast turns it into a wild Tripel

 

[dmtaylor]

It seems I'm having the same problem again, using yeast from the same resealed package. Obviously, it's the yeast (rather than fermenter or bottling bucket, which I suspected) that has been somehow contaminated.
Again, at the third week in primary the yeast has suddenly resurrected despite the cool ambient temperature and now I know where it's going to.
The batch I was talking about above came out not as bad as to dump it, still not something to be proud of either. I will have to gradually drink it up and I hate the idea to get another 8% alc. substandard batch of similar kind.

What's your opinion, if adding Campden might help to stop the wild fermentation before the gravity drops too low?
To hell with carbonation, I need to save my nice and pretty Blond before the contaminated yeast turns it into a wild Tripel

Are you certain that it's contaminated? This is a fussy yeast. But assuming you are correct:

Campden can kill bacteria and maybe some wild yeasts. It won't kill commercial yeast, but will piss them off. Your plan will be effective, and you can still get carbonation. It will just take time. Expect sulfur and diacetyl for a month or three. Eventually it will fade and you should end up with a drinkable beer.

 

[Miraculix]

I would say the exact opposite.

Camden does not kill yeasts but slows them down or inhibits their reproduction. This means what's already in there, will be in there afterwards plus it will be stressed and produce off flavours.

 

[Protos]

Thank you gentlemen!
Well, regarding the certainity of infection the gravity hasn't dropped yet into the Disaster Range (so I've got some time to salvage the beer) but the previous batch with this same yeast went south exactly the same way: resumed fermentation and then overattenuation down to 1.000.
M47 never behaved like that in my many previous batches with it, so infection is a solid suspicion.

Now I'm a bit confused about using Campden. If it won't really work, then only Pasteurization remains as an option to stop the wild fermentation

 

[Miraculix]

Thank you gentlemen!
Well, regarding the certainity of infection the gravity hasn't dropped yet into the Disaster Range (so I've got some time to salvage the beer) but the previous batch with this same yeast went south exactly the same way: resumed fermentation and then overattenuation down to 1.000.
M47 never behaved like that in my many previous batches with it, so infection is a solid suspicion.

Now I'm a bit confused about using Campden. If it won't really work, then only Pasteurization remains as an option to stop the wild fermentation

Doesn't have to be wild, could be also just a dash of belle saison in there by accident.... Mj mixes yeasts.


Pasteurisation would certainly work. I've done that before with mead and cider.

 

[Miraculix]

I've read that some folks just place their closed bottles in the dishwasher on highest temperature setting and let them run through. Should work actually. Positive side effect, if a bottle cracks, it's inside the dishwasher.

 

[Protos]

Yep, I suspect it's rather a Saison infection than a wild one, indeed (this infection doesn't produce any prominent smell, besides the overattenuation). The second layer of yeast that's precipitating now (just like it was with the previous batch) isn't creamy like in M47 but tawny like in Belle Saison. I don't think its Mangrove Jack's fault (if it was, I'd have a nice chance to sue them out of free yeast supply for the next 5 years), but it's a mystery to me how did it manage to catch a Saison bug when I keep my Diastatic yeasts in a separate container in the fridge O_O

 

[Alan Reginato]

Don't call it substandard... if It's saison yeast, they're nice!

 

[dmtaylor]

but it's a mystery to me how did it manage to catch a Saison bug when I keep my Diastatic yeasts in a separate container in the fridge O_O

Might be time to replace all your hoses, gaskets, o-rings, plastics. It's hiding out in your fermentation equipment somewhere.

 

[Zambezi Special]

Curious to see how this ends.
I'm currently brewing a saison and M47. Getting a bit worried...

 

[Protos]

It's hiding out in your fermentation equipment somewhere.

Don't think so. Perfect beers have been brewed with the same equipment between and after those two unfortunate batches. Now I'm sure it's exactly the yeast that's been infected. I've had a similar problem with M21 some time ago: whatever I brewed with it, it's spoiled. Upon opening a new sachet, all worries are gone.
That's one of the very few downsides of splitting a yeast sachet between several smaller batches. From dozens, I got just two resealed sachets infected. Which is still a weak consolence.

 

[Protos]

Don't call it substandard... if It's saison yeast, they're nice!

But the beer came out a really substandard Saison as far as Saisons go. The beer was conceived as a Belgian Blond, i. e. not a very dry style, so it got quite a bit of White Candy Sugar added to the grist, just for digestability. Because of that, the unintentionally resulting Saison came out super dry, and at 8% ABV such a dry beer is a bit tough to drink.
Maybe, it's good to get well pissed with, but even for such a noble purpose I prefer to employ some chewier brews

 

[HM-2]

Because of that, the unintentionally resulting Saison came out super dry, and at 8% ABV such a dry beer is a bit tough to drink.

Sounds like it would be great blended with a kilo or so of Morello cherry puree.

 

[Protos]

A followup, just for the statistics.
Bottled the problem beer. No overattenuation at all. Despite that, the fermentation was obviously abnormal: a second slightly darker layer of yeast precipitated onto the bottom, yeast flavours characteristic to M47 are considerably muted, the beer is still cloudy after a month in the primary. Far from what M47 used to behave like in my previous healthy batches.
Conclusion: it seems I've got an infection indeed, though not the same Diastatic kind as in my previous failed batch inoculated from the same sachet.
At least, the batch came out as a usable beer. Nothing to write home about but not a dumper either.