bubbles during Lacto souring

[WhamFish]

I've got a 5 gal carboy that I've got full of wort. I pitched a starter of L. brevis and was waiting for it to sour, holding it at 105F. Ive had it there for 48 hours. pH is 4.0, not much lower than where it started.

Now it is bubbling, like soda, no head retention, no krausen. Just a steady stream of bubbles. The starter didn't bubble, and absolutely nothing else went in there. I did my normal sanitation protocol.

Question is: should I just pitch yeast? is this potentially dangerous? Like could something have got in there that will make me sick? If I pitch and the ferment takes it down to the expected gravity will I need to worry about something being in there that would be bad for me?

 

[kingwood-kid]

The dangerous things that can develop in wort are eliminated when the pH drops to around 4, whether it's yeast or bacteria that gets you there. What pH did you start at? Most wort has a pH in the low 5 range.

 

[WhamFish]

I lowered the pH to 4.5 with lactic acid just before tossing in the Lacto starter.

So Just because the pH is below 4 does that mean the things that grew in it prior to the pH dropping are no worries too?

What sort of thing would be eating my wort then?

 

[TAK]

Could just be heterofermative lacto. That would be my guess, anyway.

 

[D-Train]

I did this recently. I cultured lacto from grain. Pitched into a no-boil Berliner and set to 110F. After 48 hours I heated to pasteurization temps and then pitched 1007. Now that it's finished I found it did not sour much and I cheated by adding lactic acid in the keg. Mine also had a krausen very much like what you've described. I think you're on the right track to take daily pH measurements until you get the desired level of sourness.

 

[jnacey]

Could just be heterofermative lacto. That would be my guess, anyway.

I agree. Brevis is heterofermative, so, in addition to lactic acid, it will produce CO2 and alcohol.

 

[WhamFish]

Seems reasonable, but why didn't I observe any bubbles in the starter?

I guess this is the most reasonable answer though since I put 500ml of Lacto starter in there, would seem odd that something else would win out first. I'll continue to take pH readings to see if it drops to 3.0, if so I guess its just the Lacto that is responsible.

 

[jnacey]

Did you have it on a stir plate? Where was the brevis from?

 

[brwagur]

Also, what were the IBUs of the wort? I remember reading the IBUs can affect lactobacillus metabolism, even when they do not inhibit it.

 

[ColoHox]

There is nothing dangerous in there. You can pitch your yeast when you are satisfied with the sourness present in the beer. It is true that L. brevis is heterfermentative, but the flavor profile you will get at the end depends on the conditions you give the bacteria to work in.

In the future, don't make a starter when using bacteria. You will get quicker and more pronounced sourness if you "underpitch" it, more or less. Also, oxygen is detrimental to the growth and survival of Lactobacilli, so avoid aeration when these bacteria are involved.

 

[jnacey]

In the future, don't make a starter when using bacteria. You will get quicker and more pronounced sourness if you "underpitch" it, more or less. Also, oxygen is detrimental to the growth and survival of Lactobacilli, so avoid aeration when these bacteria are involved.

That's not true in the case of L. brevis. Brevis actually performs better in an aerobic environment.

 

[WhamFish]

IBUs were only 5 and I do understand that sourness comes from growth phase but I like to get several beers out of this one Lacto pack so I made a starter so I could keep the strain going for future batches.

 

[WhamFish]

Fermentation is going along just fine, pH is still 4 though

 

[jnacey]

What company is the brevis from?

 

[ColoHox]

That's not true in the case of L. brevis. Brevis actually performs better in an aerobic environment.

L. brevis is a facultative anaerobe. So, it can grow in the presence of oxygen, but it does not prefer to. Varying oxygen concentration in the wort is a good way to influence the type of sugars used and the flavor profile of the acidity, ie. oxygen promotes acetic acid formation by L. brevis.

A more consistent and reliable fermentation with Lactobacillus is achieved when the oxygen concentration is purposefully reduced.

 

[jnacey]

L. brevis is a facultative anaerobe. So, it can grow in the presence of oxygen, but it does not prefer to. Varying oxygen concentration in the wort is a good way to influence the type of sugars used and the flavor profile of the acidity, ie. oxygen promotes acetic acid formation by L. brevis.

A more consistent and reliable fermentation with Lactobacillus is achieved when the oxygen concentration is purposefully reduced.

That's just not true. In lab settings, brevis exhibited 50% more growth under aerobic conditions.

http://aem.asm.org/content/15/5/1025.full.pdf

 

[ColoHox]

That's just not true. In lab settings, brevis exhibited 50% more growth under aerobic conditions.

http://aem.asm.org/content/15/5/1025.full.pdf

Without getting this thread too off course...there is a difference between cell yield/growth (aerobic respiration) and production of organic acids (anaerobic fermentation) in the aerotolerant species. As a genus, all of the Lactobacilli are facultative anaerobes or anaerobic.

Often, and applicable to other species of Lactobacillus, the cell yield is higher under aerobic growth conditions but, the acid production (which is why we are using these strains) is higher in anaerobic conditions. There are also more than 50 different strains of L. brevis, some which can grow in beer and others which cannot, some which can only grow in wheat beer but not pilsner beer (mostly relating to hop tolerance), so there is a lot of variability. Unfortunately, we don't know if the L. brevis strain described in the paper you linked (B155) has any relevance to the strain(s) that are distributed by the yeast companies, but it certainly has high cell yield in the presence of oxygen in that paper. Interestingly, it is one of the only strains of L. brevis that also produces an anti-bacterial compound.

Basicallly, what it boils down to, is that the cells may grow fine with oxygen, but they only produce lactate and acetate in the absence of oxygen. So, you're right in that an aerated starter pitched into a (mostly) anaerobic wort would be best.

 

[WhamFish]

Without getting this thread too off course...there is a difference between cell yield/growth (aerobic respiration) and production of organic acids (anaerobic fermentation) in the aerotolerant species. As a genus, all of the Lactobacilli are facultative anaerobes or anaerobic.

Often, and applicable to other species of Lactobacillus, the cell yield is higher under aerobic growth conditions but, the acid production (which is why we are using these strains) is higher in anaerobic conditions. There are also more than 50 different strains of L. brevis, some which can grow in beer and others which cannot, some which can only grow in wheat beer but not pilsner beer (mostly relating to hop tolerance), so there is a lot of variability. Unfortunately, we don't know if the L. brevis strain described in the paper you linked (B155) has any relevance to the strain(s) that are distributed by the yeast companies, but it certainly has high cell yield in the presence of oxygen in that paper. Interestingly, it is one of the only strains of L. brevis that also produces an anti-bacterial compound.

Basicallly, what it boils down to, is that the cells may grow fine with oxygen, but they only produce lactate and acetate in the absence of oxygen. So, you're right in that an aerated starter pitched into a (mostly) anaerobic wort would be best.

Thanks for the detailed reply, and please don't apologize for taking this off topic. Rather, this is exactly on topic of what I'm hoping to learn from posting on here.

So I've read much of this from various sources on the internet, I understand that Lacto can grow with and without oxygen and that lactic acid production is the primary product in the absence of O2.

What I'm not understanding is what causes CO2 production or no CO2 production. It is my understanding that in the absence of O2 you get a reaction that yields Lactic acid as its end product with no CO2 as a byproduct. In the presence of O2 the bacteria uses the O2 to produce acetate and CO2.

In a carboy shouldn't the O2 then run out leaving the lactic acid pathway as the only available pathway?

Where am I getting off track here?

 

[ColoHox]

The presence or absence of CO2 is determined by the fermentation pathways used by the various species of Lactobacillus. This is where the designation of homofermentative and heterofermentative come from: Homofermenters convert sugar (glucose) into lactic acid, heterofermenters convert sugar into lactic acid, CO2, and ethanol. Other compounds are obviously produced as well, but that is the general breakdown. The different strains have different metabolic pathways for the use of sugars. There are strains that are obligate heteros and facultative heteros, meaning some strains must use a particular path and others can actively change their metabolism. Some strains will only produce these acids without oxygen and are actively inhibited by oxygen.

The end result of using these different strains in beer is not solely dependent on the presence or absence of oxygen, but also on temperature, pH, and the composition of sugars available, eg. fructose vs glucose.

Even homofermenters (species which normally only produce lactic acid) can produce mixed acids (lactic, acetic) if they are grown in conditions that they do not find favorable. This is part of the reason why reports of souring beers can be so variable, even when the same strain is used.

Using a heterofermenter as an example (which L. brevis is), or a generally aerotolerant heterofermenter, the available oxygen will be used for aerobic respiration and production of cell mass, as this is a more energy efficient process (there is also limited production of the acids during this phase). Without oxygen, metabolism switches to anaerobic fermentation, which is less energy efficient, but produces more of the products WE are interested in. During this process the heterofermenters will produce CO2, in addition to the other products I mentioned.

While the results can vary, in general, a heterofermenter will likely produce a sour beer slower than a homofermenter, due to the concurrent production of the other byproducts of the pathway, but growth conditions have a major impact. Your last statement is right: once oxygen is used up, the bugs will switch to anaerobic fermentation and sour your beer. You can help that process along by providing appropriate conditions. The bacteria are just trying to survive, we have to manipulate them into doing what we want them to do.

 

[WhamFish]

Thanks, between you explanation there and this link I think I've got it.
http://dwb4.unl.edu/Chem/CHEM869P/C...du/microtextbook/metabolism/Fermentation.html

I was mis-understanding the heterofermenter pathways.

I do have another question if you'll forgive my ignorance in bio-chem. I'm a microbial geneticist, I'm a lot more comfortable with genetic data than I am with chemical pathways.

Do the bacteria follow from glucose all the way to ethanol CO2 and lactic acid all at once or can they build up some of the intermediate first only to come back to finish the full pathway later.

As in a yeast fermentation that builds up a substantial bit of acetylaldehyde until the very end where it goes back and finished cleaning that up by converting it into ethanol.

 

[jnacey]

Here's a chart of a heterofermatative pathway.

https://i0.wp.com/textbookofbacteriology.net/heterolactic.jpg

 

[ColoHox]

Lactic acid fermentation is the niche of Lactobacillus. It is in the best interest of the bacteria to complete the pathway and gain the maximum amount of benefit.

So in a perfect culture, you theoretically yield: In homofermenters, 1 mole lactic acid for every one mole glucose; in heterofermenters, one mole each of Lactic acid, CO2, and ethanol. Of course, this gets completely messed up all the time. Sometimes with mutations that affect enzymes in the pathway, and sometime by the culture conditions.

Speaking of messed up, I need to eat some crow. L. brevis does require oxygen for fermentation, as it is deficient in the ethanol production portion of the heterofermentative pathway, and it's the only floccing one that does this. So its primary endproducts are acetic acid, CO2, and lactic acid, theoretically. Sorry, jnacey, I'll ride slower.

Sometimes, in less-than-perfect cultures, which beer certainly is, a build up of the intermediate pyruvate can influence homofermenters to produce diacetyl when oxygen is present. In heterofermenters, oxygen presence disfavors the ethanol branch of the pathway and pushes acetate production. A lot of this is just taxonomy BS; because the metabolism is so variable, the classifications (hetero vs homo) are a bit to general, but necessary for basic separation.

Maybe you'll like this and this and this.

 

[jnacey]

Lactic acid fermentation is the niche of Lactobacillus. It is in the best interest of the bacteria to complete the pathway and gain the maximum amount of benefit.

So in a perfect culture, you theoretically yield: In homofermenters, 1 mole lactic acid for every one mole glucose; in heterofermenters, one mole each of Lactic acid, CO2, and ethanol. Of course, this gets completely messed up all the time. Sometimes with mutations that affect enzymes in the pathway, and sometime by the culture conditions.

Speaking of messed up, I need to eat some crow. L. brevis does require oxygen for fermentation, as it is deficient in the ethanol production portion of the heterofermentative pathway, and it's the only floccing one that does this. So its primary endproducts are acetic acid, CO2, and lactic acid, theoretically. Sorry, jnacey, I'll ride slower.

Sometimes, in less-than-perfect cultures, which beer certainly is, a build up of the intermediate pyruvate can influence homofermenters to produce diacetyl when oxygen is present. In heterofermenters, oxygen presence disfavors the ethanol branch of the pathway and pushes acetate production. A lot of this is just taxonomy BS; because the metabolism is so variable, the classifications (hetero vs homo) are a bit to general, but necessary for basic separation.

Maybe you'll like this and this and this.

No worries my man. Would you oxygenate wort prior to adding brevis? I've always done the oxygenated starter for growth, but then a wort that only gets aeration from transfer and some minor splashing.

 

[ColoHox]

No worries my man. Would you oxygenate wort prior to adding brevis? I've always done the oxygenated starter for growth, but then a wort that only gets aeration from transfer and some minor splashing.

While L. brevis requires oxygen to complete its metabolism, it is still a microaerophile, to throw another term out there. So, the 4-8ppm of oxygenation you get from transfer and splashing should be perfect. The lactate and acetate pathways do not require oxygen, but to squeeze another ATP out of the reaction, the acetolactate pathway is used, which requires O2.

L. brevis has a defective ADHE enzyme (bottom left of picture), so the reaction is pushed towards the bottom right branch of the picture where O2 can participate.

Do you ever taste diacetyl in these beers? It would be interesting to see how long it takes for a L. brevis-only fermentation to reduce diacetyl to the following compounds with lower flavor thresholds.

 

[jnacey]

I don't taste diacetyl with them, but I usually only let the lacto go to a ph of around 3.3 - 3.4 and then I toss in a brett strain to take over fermentation.

 

[WhamFish]

Lactic acid fermentation is the niche of



Maybe you'll like this and this and this.

Cool, thanks for the links.

 

[berebrando]

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.

 

[WhamFish]

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?

 

[jnacey]

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?

A ph that low is excessively acidic. Most of the world class sours are actually more in the 3.1 - 3.4 range.

http://embracethefunk.com/ph-readings-of-commercial-beers/

I've found that these beers that just get started with lacto and then receive a pitch of either sacc/brett do not come out nearly as complex as a long aged Lacto/sacc/brett/pedio blend. These quicker ones are a bit one dimensional, but make for great aging on fruit. I'd love to get my hands on a rare barrel or cascade bottle to culture up those dregs as they seem to have a better character than I'm getting with the commercial pitches of lacto. Cheers.

 

[kingwood-kid]

A pH of 3 in a bone-dry beer is very different from a pH of 3 in a beer with a comparative abundance of residual sugars. Most of the residual sugars aren't particularly sweet but do add body. We focus a great deal on the funk and sourness that non-sacch microbes produce, but their extreme attenuation has the additional effect of revealing a lot of what was hiding in the beer already.

 

[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.