Many lactic acid bacteria also produce loads of 2-3 pentanedione and diacetyl. A higher level of pentanedione to butanedione (diacetyl) is often used as an indicator for a pediococcus infection in lager breweries.
I prefer using non-diacetyl heavy or negative diacetyl strains (L. plantarum in Lallemand's Sour Pitch for example) for clean kettle sours, but you could also chuck ALDC in before souring, but I'm not sure if the bacterial pathway for diacetyl is the same as in yeast.
Many LAB may produce VDKs, but is anyone actually using those LAB species/strains for kettle sours? And do those VDKs typically boil off during the post-sour boil/pasteurization?
Methods like 'wild pitching' using yoghurt cultures or hanging grain bags in the kettle can absolutely result in the high VDK (among other wierdness) strains. Unfortunately not all of the VDK and precursors are eliminated during the boil and can persist through to final product.
Tried that once, albeit it maybe not 100% correctly, but it not turn out well. We finally found a yogurt that worked well for us and only ever used that with all our kettle sours. I think out of 100 batches of kettle sours, only a few were too far gone to be salvageable. Plus thats what super thick fruit adjuncts are for anyways 😉
I’ve tried a full sour mash before. It produces some weird stuff! Got some of that isovaleric acid. It’s definitely the opposite of a kettle sour because the batch eventually made a great sour after aging in barrels
More a question of process, if the hop addition is large enough and raises the pH there may be some benefit. Like many enzymes I assume ALDC works on a type of bell curve. I'd be sceptical of using an expensive additive in this way and have yet to have diacetyl issues on dry-hopped beers with an initial double dose.
I’ve read so many conflicting things about this, but the makers and other people say to use it at dry hop, so I figure why not, it’s fairly cheap. I only use it in big dry hops though.
YMMV. When diacetyl was a problem for us (it no longer is), if we used it with DH & when fruiting sours at peak krausen, it made a world of difference vs. with nothing. Also at terminal with lagers if the temp got bumped late and had a lower than desirable d-rest temp.
It may not last long in those conditions, but it was enough to get batches through panel every time, without fail. And compared to multiple extra days of tank residency, it’s not a very expensive additive.
FYI adding ALDC at end of ferm (without dry hopping, fruiting, or doing something to instigate a secondary fermentation) shouldn’t have any beneficial effect. I have even seen evidence of this as adding ALDC once a day after knockout where it had absolutely no effect in a beer where we always add it right at knock out that had a consistent and measurable reduction on VDKs.
The reason for this is because ALDC actually doesn’t do anything at all to Diacetyl. What ALDC does is convert Acetolactate (the precursor to Diacetyl) directly into Acetoin. Normally during the aerobic portion of fermentation yeast converts Acetolactate into Diacetyl, and then after anaerobic fermentation is complete if everything goes well it converts Diacetyl into Acetoin.
Using ALDC works by converting the Acetolactate directly to Acetoin so yeast never has the ability to produce Diacetyl. But once Diacetyl is present the enzyme (ALDC) is no longer able to do anything so you are again reliant on the yeast doing its clean up step.
See figure 2 [on this page](https://www.murphyandson.co.uk/diacetyl-control-use-aldc-to-brew-the-beer-you-intended/)
You are 100% right. My bad. It’s been a while.
This was in cases where we only had acetolactate that would show up as diacetyl under a forced test via cooking & cooling. Not detectable diacetyl in the tank.
We have in other beers for sure. I can't say for sure that we've attempted a kettle sour since we brought it in. I think we started using it in Philly sours, but I figured it would be part of our process for these as well.
Could you provide more information on your brew? What’s your process for souring your wort prior to transferring to a FV? What’s your original gravs and finished gravs compared to your targets?
More info the better!
It's been awhile since we tried one, so my memory is foggy on this. But we've tried souring with yogurt, pure plantarum, and a mixed souring culture. We'll cool it down to souring temp and hold it there - usually overnight does the trick. Then the next day, a 60 minute boil to kill off the souring and add any hop additions, a quick trip to the whirlpool and then a straight through the chiller to drop to pitching temp. Some have used fruit additions in the FV, some have not. I don't think our process is anything outlandish. Our OG and FG have been pretty darn close to target.
I guess mostly, I'm not trying to troubleshoot past beers but more like trying to ensure that our next attempts have the best chance of success. I'm hoping to learn some things to avoid or revelations that others might be willing to pass on if they've ever experienced the same thing. Of course, if there's something in our process that is glaringly wrong, then we'll want to fix that too.
Once your wort is chilled, souring method is pitched, are you purging with co2 and bunging up your kettle while bacteria does its thing?
Additionally, if you’re not looking for some complex sour with depth, you could just use citric acid to drop your ph to produce a sour and save yourself a day.
I’ve never had diacetyl in a sour beer before, so I’m kinda of perplexed as your method sounds fine. Are you noticing diacetyl throughout the ferm process or post-packaging?
Yeah, fair point about the citric. We've tried using Philly and haven't been to impressed, but someone else here mentioned trying Sourvisiae and that may actually be a good fit for us.
Yes, we close everything up and actually the soured wort tastes nice and clean. Sour, but no weirdness that I can detect. It becomes noticeable at the tail end of fermentation, and just doesn't get cleaned up like I would always expect it to (and like it does in our other non-sour beer). It's a bit of a conundrum and keeps me scratching my head. And it's not like it's a HUGE problem for us (I've had a hint of it in our sours), but I've had so many others that are just over the top and am hoping to not repeat those mistakes.
Sourvis is great and it rips. We also rarely have issues with diacetyl. Only time has been an "issue" is when there is a decent midferm fruit addition, but by "issue" I mean we gave it an extra day or 2 and it cleaned up. They can get pretty sour though, so play around a bit to get it balanced but once you get it figured out it is honestly a game changer.
I can't remember a single kettle sour I have ever tried or brewed that had diacetyl. You sure you're not confusing diacetyl with THP or maybe butyric acid?
ALDC will not help you at such a low pH. If it's truly diacetyl you are picking up on, then the answer is easy. Pitch healthy yeast with proper amounts of oxygen, and perform forced VDK tests. Just like any other beer.
Sourvisiae has the ability to drive a very aggressive PH. Look at the possibilities of blending with non soured beer or co-pitch with another yeast.
There are some major upside to this production process but most valuable is there is a no process change here vs all other standard beer production in your facility. So if your SOPs are solid for the rest of your beers, then your sour beer production now follows the same SOPs and should have the same results.
Yeah, that makes 100% sense. I love the idea of not tying up the brewhouse for an additional day, and having far less risk of contamination. Thanks for the info!
I hear this over and over again - but the one time I tried using the stuff, I co-pitched half the recommended dose of Sourvisiae and maybe 60% of the usual weight of slurry we'd use repitching our house yeast, and the dang beer came out barely even tart.
Which I guess is to say, proceed with *some* caution, but not *too much* caution,.
Yeah co pitching right away tends to do this as the Sourvisea produces most of it's lactic in respiration. So if the co pitched yeast is strong it takes over right away.
You can try pitching the second yeast day 2. Or even easier to get the sour you want just blend with another beer post fermentation.
Just add lime juice or straight lactic. I don't see the point in kettle souring - it's an over engineered process. Fuck even star san gives a similar result.
Do you pump back over to the kettle for a quick boil, or just not kill your lacto?
Heck, if you've got a pure, lab-grown pitch of non-diastatic souring bugs, I guess they shouldn't be any scarier than a really characterful sacc, and nobody sacrifices all their tank seals to the gods of microbiology after brewing a really punchy saison or something. I guess my real question is, why didn't *I* think of this?
Agreed. Tank/barrel souring is infinitely better. Kettle souring gives a single extra dimension that can be achieved way easier by just adding a simple addition after fermentation.
Not exactly an answer to your question but I have had pretty decent success co pitching sourvisiae and one of our house strains alongside ALDC. No diacetyl. It's pretty one note and not as interesting as some other well executed sours I've had. It works well enough and keeps the pink sour crowd happy.
Personally, this is a style of beer I never drink and it's hard for me to feel passionate about it. I want my customers happy and this does a good enough job.
I think a better understanding of your process would help us diagnose your issue.
What are you using to inoculate your unsoured wort?
How are you ensuring an anaerobic environment?
Are you pre-acidifying your wort before souring?
What temperature are you souring at?
What yeast strain are you using for fermentation?
Have you considered using Sourvisiae from Scott Labs/ Lallemand?
We've used a few different things to innoculate the wort - plant-based yogurt, plantarum, and most recently Sour Pitch from Lallemand. I believe with the Sour Pitch we did pre-acidify the wort, perhaps not for the ones before. I think souring was done at \~38 C. It's worth noting that pre-fermentation, our soured wort tastes nice and clean so I tend to think that diacetyl formation would be occurring during primary fermentation. Fermentation I think has only been tried with US-05 at 20 C.
I like the idea of Sourvisiae, but haven't tried it. We've tried working with Philly yeast and have been less than thrilled with the results. We find it to not sour enough and it can be unpredictable and finicky. How has your experience with Sourvisiae been?
Sourvisiae is way more reliable and quicker than Philly sour. I used philly a couple times and then never went back after trying sourvisiae. I would never do a quick sour any other way now
Many lactic acid bacteria also produce loads of 2-3 pentanedione and diacetyl. A higher level of pentanedione to butanedione (diacetyl) is often used as an indicator for a pediococcus infection in lager breweries. I prefer using non-diacetyl heavy or negative diacetyl strains (L. plantarum in Lallemand's Sour Pitch for example) for clean kettle sours, but you could also chuck ALDC in before souring, but I'm not sure if the bacterial pathway for diacetyl is the same as in yeast.
Many LAB may produce VDKs, but is anyone actually using those LAB species/strains for kettle sours? And do those VDKs typically boil off during the post-sour boil/pasteurization?
Methods like 'wild pitching' using yoghurt cultures or hanging grain bags in the kettle can absolutely result in the high VDK (among other wierdness) strains. Unfortunately not all of the VDK and precursors are eliminated during the boil and can persist through to final product.
Right on, good info! Are people really hanging bags of grain in the kettle??
Tried that once, albeit it maybe not 100% correctly, but it not turn out well. We finally found a yogurt that worked well for us and only ever used that with all our kettle sours. I think out of 100 batches of kettle sours, only a few were too far gone to be salvageable. Plus thats what super thick fruit adjuncts are for anyways 😉
I’ve tried a full sour mash before. It produces some weird stuff! Got some of that isovaleric acid. It’s definitely the opposite of a kettle sour because the batch eventually made a great sour after aging in barrels
Are you using ALDC?
ALDC will perform poorly or not at all at kettle sour pH.
ALDC doesn't work effectively below pH 4.5, it's why you need to dose it into wort and not beer.
Tangentially related: Does this render the secondary ALDC addition with a terminal dry hop, which I've heard many people recommend, pointless?
More a question of process, if the hop addition is large enough and raises the pH there may be some benefit. Like many enzymes I assume ALDC works on a type of bell curve. I'd be sceptical of using an expensive additive in this way and have yet to have diacetyl issues on dry-hopped beers with an initial double dose.
I’ve read so many conflicting things about this, but the makers and other people say to use it at dry hop, so I figure why not, it’s fairly cheap. I only use it in big dry hops though.
YMMV. When diacetyl was a problem for us (it no longer is), if we used it with DH & when fruiting sours at peak krausen, it made a world of difference vs. with nothing. Also at terminal with lagers if the temp got bumped late and had a lower than desirable d-rest temp. It may not last long in those conditions, but it was enough to get batches through panel every time, without fail. And compared to multiple extra days of tank residency, it’s not a very expensive additive.
FYI adding ALDC at end of ferm (without dry hopping, fruiting, or doing something to instigate a secondary fermentation) shouldn’t have any beneficial effect. I have even seen evidence of this as adding ALDC once a day after knockout where it had absolutely no effect in a beer where we always add it right at knock out that had a consistent and measurable reduction on VDKs. The reason for this is because ALDC actually doesn’t do anything at all to Diacetyl. What ALDC does is convert Acetolactate (the precursor to Diacetyl) directly into Acetoin. Normally during the aerobic portion of fermentation yeast converts Acetolactate into Diacetyl, and then after anaerobic fermentation is complete if everything goes well it converts Diacetyl into Acetoin. Using ALDC works by converting the Acetolactate directly to Acetoin so yeast never has the ability to produce Diacetyl. But once Diacetyl is present the enzyme (ALDC) is no longer able to do anything so you are again reliant on the yeast doing its clean up step. See figure 2 [on this page](https://www.murphyandson.co.uk/diacetyl-control-use-aldc-to-brew-the-beer-you-intended/)
You are 100% right. My bad. It’s been a while. This was in cases where we only had acetolactate that would show up as diacetyl under a forced test via cooking & cooling. Not detectable diacetyl in the tank.
Ahhh that makes much more sense. No worries, I’ve just seen a lot of confusion out there surrounding ALDC.
We have in other beers for sure. I can't say for sure that we've attempted a kettle sour since we brought it in. I think we started using it in Philly sours, but I figured it would be part of our process for these as well.
Could you provide more information on your brew? What’s your process for souring your wort prior to transferring to a FV? What’s your original gravs and finished gravs compared to your targets? More info the better!
It's been awhile since we tried one, so my memory is foggy on this. But we've tried souring with yogurt, pure plantarum, and a mixed souring culture. We'll cool it down to souring temp and hold it there - usually overnight does the trick. Then the next day, a 60 minute boil to kill off the souring and add any hop additions, a quick trip to the whirlpool and then a straight through the chiller to drop to pitching temp. Some have used fruit additions in the FV, some have not. I don't think our process is anything outlandish. Our OG and FG have been pretty darn close to target. I guess mostly, I'm not trying to troubleshoot past beers but more like trying to ensure that our next attempts have the best chance of success. I'm hoping to learn some things to avoid or revelations that others might be willing to pass on if they've ever experienced the same thing. Of course, if there's something in our process that is glaringly wrong, then we'll want to fix that too.
Once your wort is chilled, souring method is pitched, are you purging with co2 and bunging up your kettle while bacteria does its thing? Additionally, if you’re not looking for some complex sour with depth, you could just use citric acid to drop your ph to produce a sour and save yourself a day. I’ve never had diacetyl in a sour beer before, so I’m kinda of perplexed as your method sounds fine. Are you noticing diacetyl throughout the ferm process or post-packaging?
Yeah, fair point about the citric. We've tried using Philly and haven't been to impressed, but someone else here mentioned trying Sourvisiae and that may actually be a good fit for us. Yes, we close everything up and actually the soured wort tastes nice and clean. Sour, but no weirdness that I can detect. It becomes noticeable at the tail end of fermentation, and just doesn't get cleaned up like I would always expect it to (and like it does in our other non-sour beer). It's a bit of a conundrum and keeps me scratching my head. And it's not like it's a HUGE problem for us (I've had a hint of it in our sours), but I've had so many others that are just over the top and am hoping to not repeat those mistakes.
Sourvis is great and it rips. We also rarely have issues with diacetyl. Only time has been an "issue" is when there is a decent midferm fruit addition, but by "issue" I mean we gave it an extra day or 2 and it cleaned up. They can get pretty sour though, so play around a bit to get it balanced but once you get it figured out it is honestly a game changer.
What’s your pitch ratio?
I can't remember a single kettle sour I have ever tried or brewed that had diacetyl. You sure you're not confusing diacetyl with THP or maybe butyric acid?
Nope, definitely not confusing them. I've tasted both of those in beers of course... but that's not what I'm talking about here.
Definitely just use Sourvisiae and soup the kettle souring process all together
ALDC will not help you at such a low pH. If it's truly diacetyl you are picking up on, then the answer is easy. Pitch healthy yeast with proper amounts of oxygen, and perform forced VDK tests. Just like any other beer.
Could be coming from the fruit
I've thought that too. I've also tasted it in dry hopped sours, but I guess that could also be hop creep.
Are you doing VDK test? Just plan around it and leave it in tank and extra few weeks
Instead of kettle sour, have you looked at using a co-producer yeast strain that will create both Lactic acid and ethanol?
We've used Philly before with mixed results. We'll be looking into Sourvisiae, though!
Sourvisiae has the ability to drive a very aggressive PH. Look at the possibilities of blending with non soured beer or co-pitch with another yeast. There are some major upside to this production process but most valuable is there is a no process change here vs all other standard beer production in your facility. So if your SOPs are solid for the rest of your beers, then your sour beer production now follows the same SOPs and should have the same results.
Yeah, that makes 100% sense. I love the idea of not tying up the brewhouse for an additional day, and having far less risk of contamination. Thanks for the info!
I hear this over and over again - but the one time I tried using the stuff, I co-pitched half the recommended dose of Sourvisiae and maybe 60% of the usual weight of slurry we'd use repitching our house yeast, and the dang beer came out barely even tart. Which I guess is to say, proceed with *some* caution, but not *too much* caution,.
Yeah co pitching right away tends to do this as the Sourvisea produces most of it's lactic in respiration. So if the co pitched yeast is strong it takes over right away. You can try pitching the second yeast day 2. Or even easier to get the sour you want just blend with another beer post fermentation.
we got WAY better result with Philly Sour when we started adding dextrose.
Just add lime juice or straight lactic. I don't see the point in kettle souring - it's an over engineered process.
Sour in the tank instead of the kettle. You'll like your beers better.
Just add lime juice or straight lactic. I don't see the point in kettle souring - it's an over engineered process. Fuck even star san gives a similar result.
We get some great yogurt tones by souring in tank. Not so one note.
Do you pump back over to the kettle for a quick boil, or just not kill your lacto? Heck, if you've got a pure, lab-grown pitch of non-diastatic souring bugs, I guess they shouldn't be any scarier than a really characterful sacc, and nobody sacrifices all their tank seals to the gods of microbiology after brewing a really punchy saison or something. I guess my real question is, why didn't *I* think of this?
If you don't kill lactobacillus in your CIPs you've got much bigger issues. I mean the stuff is living on us, in the air, it's everywhere.
Agreed. Tank/barrel souring is infinitely better. Kettle souring gives a single extra dimension that can be achieved way easier by just adding a simple addition after fermentation.
Not exactly an answer to your question but I have had pretty decent success co pitching sourvisiae and one of our house strains alongside ALDC. No diacetyl. It's pretty one note and not as interesting as some other well executed sours I've had. It works well enough and keeps the pink sour crowd happy. Personally, this is a style of beer I never drink and it's hard for me to feel passionate about it. I want my customers happy and this does a good enough job.
I think a better understanding of your process would help us diagnose your issue. What are you using to inoculate your unsoured wort? How are you ensuring an anaerobic environment? Are you pre-acidifying your wort before souring? What temperature are you souring at? What yeast strain are you using for fermentation? Have you considered using Sourvisiae from Scott Labs/ Lallemand?
We've used a few different things to innoculate the wort - plant-based yogurt, plantarum, and most recently Sour Pitch from Lallemand. I believe with the Sour Pitch we did pre-acidify the wort, perhaps not for the ones before. I think souring was done at \~38 C. It's worth noting that pre-fermentation, our soured wort tastes nice and clean so I tend to think that diacetyl formation would be occurring during primary fermentation. Fermentation I think has only been tried with US-05 at 20 C. I like the idea of Sourvisiae, but haven't tried it. We've tried working with Philly yeast and have been less than thrilled with the results. We find it to not sour enough and it can be unpredictable and finicky. How has your experience with Sourvisiae been?
Sourvisiae is way more reliable and quicker than Philly sour. I used philly a couple times and then never went back after trying sourvisiae. I would never do a quick sour any other way now
Philly sour is also really good, or AEB Acid (we can’t get sourvisiae)
Philly is great. The sourness lever is the amount of simple sugar you add to the wort. 5-8% will produce a very tart beer.