bubbles during Lacto souring

[ColoHox]

I just have to say that this conversation is fantastic. I learned a lot and this is very timely for me.

I have used 677 to produce a lightly tart wheat beer that worked great with different fruits. But it didnt have the right level of sourness - I want more! I'm getting ready to re-create that tart wheat beer on a big scale (15 bbls), but still trying to figure out which Lacto or blend to use.

Unless you are going to tailor a wort for a particular species of Lactobacillus, I think you should pitch a blend. A controlled Lacto fermentation is just as important as a controlled lager fermentation. We know specific temperature ranges of particular yeasts and manipulate them for specific styles of beer. These things hold true for Lacto fermentations as well. A blended culture fermentation gives you a little more leeway when creating your wort, and potentially a more complex sourness. Alternatively, a controlled fermentation of by a selected species of Lactobacillus will/should give a quick and specific sour profile that could be blended into another batch to achieve particular flavors. If you can't be bothered to monitor and potentially adjust temperature, pH, and oxygenation then just go with a blend. If you are making 15bbl, you likely have the equipment to control a fermentation like this. Do you have 2 7bbl fermenters? Zero aeration with a pitch of Lactobacillus in one and a aerated Sacch pitch in the other then blend. Do you use pH and/or DO meters?

I did do an experment about a week ago with several sources of Lacto, including yogurt and kefir and L brevis from Wyeast. They all took the 1.020 DME starter to a pH of 3.0 then stopped.

pH of 3.0 is medium tart but not as sour as many great sours. Although im sure there is some variation in the pH tolerance in Lacto species, I suspect that it takes more than Lacto alone to get a beer to go into the 2.6-2.9 range.

Anyone have any experience getting a beer below 2.9 with Lacto alone?

Lactobacillus is severely inhibited at pH <3.8 and Brett at pH<3.4. pH is a technical measure for a single aspect of the beer and does not always correlate to actual sourness or percieved sourness for that matter, similar to what kingwood-kid mentioned. A pH 4 beer with the acidity comprised mainly of lactic acid will taste differently than a pH 4 beer with acidity comprised of mixed acids from normal fermentation processes. pH lower than the functional range of the sour bugs is due to carbonation, aging, remaining metabolic process from the few active and dying bugs.

 

[WhamFish]

Just an update on the beer from the OP, it continues to ferment and is dropping gravity. pH is 3.9 but the biggest thing is that it is a DMS BOMB! Base malt is ashburn mild and I did a 60min boil with my typical immersion chiller. Not sure if this is additional evidence to support an unwanted infection or if this is just a result of the present fermentation. I do understand that some fermentations can kick off some DMS so I'm going to stick with it till it reaches FG.

on a side note, I have a second beer going now that I've added L. brevis and L. planterum to, its 36 hour in and there are no signs of bubbles this time.

 

[berebrando]

Unless you are going to tailor a wort for a particular species of Lactobacillus, I think you should pitch a blend. A controlled Lacto fermentation is just as important as a controlled lager fermentation. We know specific temperature ranges of particular yeasts and manipulate them for specific styles of beer. These things hold true for Lacto fermentations as well. A blended culture fermentation gives you a little more leeway when creating your wort, and potentially a more complex sourness. Alternatively, a controlled fermentation of by a selected species of Lactobacillus will/should give a quick and specific sour profile that could be blended into another batch to achieve particular flavors. If you can't be bothered to monitor and potentially adjust temperature, pH, and oxygenation then just go with a blend. If you are making 15bbl, you likely have the equipment to control a fermentation like this. Do you have 2 7bbl fermenters? Zero aeration with a pitch of Lactobacillus in one and a aerated Sacch pitch in the other then blend. Do you use pH and/or DO meters?

I have collected several Lactobacillus strains at this point, including Wyeast, White Labs, Yeast Bay, Omega, and dregs of Rare Barrel and Sante Adairius Rustic Ales (two beers that I know will not spread Pediococcus around my brewery), and my house blend of Bsi Drie and clausenii. I may also pull out some beer from a barrel innoculated with Gigayeast Fast Lacto and WY L brevis. I know the SARA dregs also will contain a saison strain, too. I think this combination will give me a solid blend of strains that are hearty and quick.

Aeration is a weird topic for these beers - especially because it will contain Brett and Sacc in small quantities. I think that by not aerating I might get some weird flavors out of the yeast. Based on an email exchange with Omega, I plan to begin fermentation at 70F with a free rise. I will use a pH meter to monitor this beer over the course of fermentation.

Should all these strains be pitched together or separate? I'm going to try all-at-once because I like to try and eliminate variables that are fairly uncontrollable in the future. I will keep each culture separate in the propagation stage so that I can go back in the future to adjust the pitching schedule. Hoping that in the end, the bacteria and yeast slurry blend can be reused without rebuilding each strain up separately.

A final question is about propagation: I'm building up these cultures from homebrew pitch size to 2L starter to 5 gallon carboys, then pitching into my 15bbl batch. Using the general rule of stepping up each stage by ten x. The question relates to using homofermentative Lacto strains - as I step up these cultures with a homofermentative strain, will it be safe to allow each step to sit for up to a week? Will the low-pH wort be safe with just the pitched homofermentative Lacto strain or should I pair it with a yeast to add alcohol to the mix? I'm worried about leaving a soured wort with a lot of residual sugars while I step up the yeast/bacteria.

 

[ColoHox]

Aeration is a weird topic for these beers - especially because it will contain Brett and Sacc in small quantities. I think that by not aerating I might get some weird flavors out of the yeast. Based on an email exchange with Omega, I plan to begin fermentation at 70F with a free rise. I will use a pH meter to monitor this beer over the course of fermentation.

The same line of thinking applies to Lacto as well. Aerating your wort at Sacch levels will cause the Lacto to do strange, and probably unpredictable things.

Should all these strains be pitched together or separate? I'm going to try all-at-once because I like to try and eliminate variables that are fairly uncontrollable in the future. I will keep each culture separate in the propagation stage so that I can go back in the future to adjust the pitching schedule. Hoping that in the end, the bacteria and yeast slurry blend can be reused without rebuilding each strain up separately.

If you pitch the blend and you get the sour profile you want, then go for it. I think that process leaves too many variables, personally. Maybe it is analogous to pitching a lager strain with an ale strain, fermenting at a median temperature, and hoping to get strong results from each yeast. How about pitching your bacteria warm, letting it do its thing, then cooling, aerating and pitching your yeast? Then you kind of have two distinct phases for the two distinct organisms to work. You could still crash and pull-off the slurry between phases.

A final question is about propagation: I'm building up these cultures from homebrew pitch size to 2L starter to 5 gallon carboys, then pitching into my 15bbl batch. Using the general rule of stepping up each stage by ten x. The question relates to using homofermentative Lacto strains - as I step up these cultures with a homofermentative strain, will it be safe to allow each step to sit for up to a week? Will the low-pH wort be safe with just the pitched homofermentative Lacto strain or should I pair it with a yeast to add alcohol to the mix? I'm worried about leaving a soured wort with a lot of residual sugars while I step up the yeast/bacteria.

I guess that depends on how sterile your process is. Do you have problems with contamination of other cultures? Why wouldn't you step up your cultures at the same time, or prop your yeast while the Lacto is working? Am I misunderstanding something?

 

[berebrando]

The same line of thinking applies to Lacto as well. Aerating your wort at Sacch levels will cause the Lacto to do strange, and probably unpredictable things.

If you pitch the blend and you get the sour profile you want, then go for it. I think that process leaves too many variables, personally. Maybe it is analogous to pitching a lager strain with an ale strain, fermenting at a median temperature, and hoping to get strong results from each yeast. How about pitching your bacteria warm, letting it do its thing, then cooling, aerating and pitching your yeast? Then you kind of have two distinct phases for the two distinct organisms to work. You could still crash and pull-off the slurry between phases.

I guess that depends on how sterile your process is. Do you have problems with contamination of other cultures? Why wouldn't you step up your cultures at the same time, or prop your yeast while the Lacto is working? Am I misunderstanding something?

I am going back and forth between pitching the bacteria and yeast separately, and all together. Your description makes me lean towards the former - pitching bacteria first, allowing it to reach a desired pH, then pitching the yeast. This was the methodology recommended by Omega.

I plan to keep the strains separated and I'll keep feeding them over time. I don't normally have contamination problems. I'm planning to propagate the bacteria and yeast in isolation mostly because I already have the equipment in place. This gives me the added option of adding or subtracting strains from the blend in the future.

 

[WhamFish]

Just to report back on the beer from the OP:

It continued to ferment somewhat vigorously for about 10 days, it has slowed down now to just a steady fizz that keeps the airlock moving 2-3 times a min. The gravity is 1.020 and that hasn't changed very much at all in the last 2-3 days. With an OG of 1.053 that puts current ABV at %4.15.

The DMS like smell is still there, although it has an element of gym socks to it as well. I'm not sure if what I'm identifying as DMS is a result of my process or if it is a symptom of infection. I've got 3 beers going now that I've soured pre-primary like I did with this one and it is the only one that started bubbling on its own thus far. It is also the only one with the DMS smell. On the other hand, I only boiled this one for 60min so maybe it was that. It is also the most sour of the 3 for sure. In any case jury is still out on this one, hope the smell clears out by the time it finishes. This may or may not turn out to be a dumper.

 

[burninator]

Any update to this, OP? I'm really interested to hear how (if) it turned out.