The Mixed Fermentation Thread

[marshbrewer]

What temps will Bret go down to? I'm thinking what kind of environment do I need to age a historical recipe with added Bret?

 

[matt76]

What temps will Bret go down to? I'm thinking what kind of environment do I need to age a historical recipe with added Bret?

The Mad Fermentationist article I linked to before has some information near the start under "Temperature?" for primary and secondary Brett fermentations. Broadly I read it as ale temps or maybe a little cooler.

I imagine the Victorians aged their porters in carefully climate controlled air conditioned chambers.

 

[matt76]

An update on my Brett aged Porter - I'd appreciate some input if anyone has any idea what might be happening.

I made my Porter as planned and it fermented in about 10 days with MJ M36 from 1.049 down to 1.022 - this is exactly as expected, lots of unfermentables in there and consistent with the previous (and identical) batch.

While it was fermenting I took 1L of leftover wort and used this to make a starter for my WLP645 B.Claussenii, which I left for several days at room temp. The Brett culture had a best before of 25th May 2021, so not ideal, but part of the reason I used a starter.

I transferred the main batch to a secondary FV and pitched my Brett starter - I checked the starter with my hydrometer and noted the gravity was still unchanged at 1.049. I moved the FV to a cool-ish spot under my desk, about 18-20degC.

It's been all quiet the last few days until today when the airlock has been bubbling every now and then, maybe 4-5 times per hour, consistently through the day. I have a Tilt in there which reports that the gravity hasn't budged from 1.022 since transferring to secondary.

I'm not sure what to make of this. A few ideas have floated through my mind:

• Just off gassing?
• A bit of residual M36 fermenting the starter wort?
• Could it be the Brett doing something without reducing the gravity?
• Worst case, leave it, see what the Tilt readings do and open it up in 6 months!

Anyone got any ideas from experience?

Cheers,

Matt

 

[Sadfield]

@matt76 I missed this. Could be that the presence of oxygen from transfer and the large pitch if yeast, set the yeast initially into aerobic respiration as apposed to anaerobic respiration. This results in no alcohol production and much higher co2 production until the oxygen is depleted.

How's it doing now?

 

[matt76]

@matt76 I missed this. Could be that the presence of oxygen from transfer and the large pitch if yeast, set the yeast initially into aerobic respiration as apposed to anaerobic respiration. This results in no alcohol production and much higher co2 production until the oxygen is depleted.

How's it doing now?

@Sadfield thanks for getting back to me, I appreciate your input

As noted above it was bubbling now and then (1-3 times per hour) but gravity not changing. Shortly after I made that post I noticed it dropped at a rate of about 1 point every 3 days until it stopped at 1.020 where it's been sat stubbornly for about the last week and it has now stopped bubbling.

In a way that seems characteristic of the very tail end of a normal saccharomyces fermentation, i.e. it takes a few days to bubble down those last couple of points. Except the airlock seemed to be a lot more active than I'd have expected for that.

(there is so much unfermentable dark malt in there BTW though that I'd expect a FG of about 1.020 from a saccharomyces fermentation).

I'm more then happy to leave it - not like I'm in a rush or didn't expect to drop down to 1.005 in 48 hours!

It's more I'm now really sure what to expect - I suppose a reasonable guess might be, what, 5 points out so in 3-6 months so maybe no more than 1 point or month? I.e. very slow

My only cause for concern, the only for in the ointment, is I read somewhere (think it was Milk the Funk) that Brettanomyces Claussenii (a.k.a. b. anomolus) can't ferment maltose (I think it was maltose anyway).

So that leaves me wondering if there's just not enough fermentable sugars in there for the brett to do anything. Or maybe that the brett was just too far past its best in the first place.

I dunno...

 

[Sadfield]

I wouldn't worry. Maltose is only an issue with 100% Brett fermentations, the saccharomyces used in primary will already have used the maltose. What is remaining is maltotiose and dextins. Its basically a spoilage organism that thrives on what brewers yeast can't consume, it'll get there in time.

 

[BeerCat]

Well this is interesting - in an effort to answer some of my own questions I've been googling and ended up reading some of the comments on The Mad Fermentationist:

View attachment 45402

I'm confident my plastic buckets seal very well so maybe I can get away with aging an entire 10L batch afterall - I would just transfer to a fresh FV to get the beer if the saccharomyces yeast cake and then pitch my brettanomyces.

I am aging some of mine in plastic buckets and i don't think they are as bad as people say. My buckets do seal well and will hold a little pressure but they will produce pellicles and i prefer pet so i can watch them growing. You will get a yeast cake just like any other yeast from brett and can reuse it just like any other yeast mixed with bacteria or not. Pitch rate is important if doing a 100% brett beer to ensure a healthy fermentation and full attenuation. Fermentation normally takes around 2 to 3 weeks then they will start to clear and can be kegged to drink or left to mature.
100% brett beers are really worth experimenting with so you can see how much difference there is.

 

[BeerCat]

Out of all the Lambic style beers i have brewed the only one i can recognise the same flavours in was fermented with a starter made from Geueze dregs. This is a starter i made from three bottles a few weeks ago. So far the ones i have brewed with commercial mixed pitches are a bit one dimensional, more flavour in the fast sours so i may have to keg some of them and rebrew to fill the kegs.

 

[matt76]

Little update on my Brett aged porter;

To be honest I had forgotten about it the last few weeks, tucked away under my desk and not doing anything judging by either the airlock or the Tilt in the FV. According to the Tilt it's been sat steady for ages at 1.020-1.019 at around 18degC.

But over the last day or two - I assume related to the recent warm weather - the airlock has started bubbling again.

Initially I wondered if it's just the gas in the headspace expanding, but a glance at the Tilt showed it's dropped a little to 1.018-1.017 while the temperature has risen to 24-25degC.

I wasn't sure if this small change might be down to the temperature as I'm never sure or not if the Tilt corrects automatically for temperature. But judging by the calculator on Brewer's Friend, if the temperature goes up from 20 to 25degC then we'd also expect the gravity (or at least a hydrometer reading) to go up by about a point.

So I can only assume I've had it sat there all this time a few degC too cool. To be honest it was never clear to me what temperature it wants to be at, but I suppose it makes sense - I know BRY-97 or MJ M36 will ferment perfectly well at 20degC but I wouldn't be too surprised if they stopped completely if I held them at 15degC.

 

[Ajhutch]

Time to do some “gueze” blending! Never done it before but I’ve read some blogs and articles and the chapter on blending in American Sour Beers, so I have a rough idea of how I want to go about it.

 

[Ajhutch]

So I’ve decided on 4.5 litres of the 2018 and 2020 beers and 6 litres of the 2019 to blend. Have to decide what to do with the rest of them; I’ll probably bottle the rest of 2018 as it is as it’s a really nice complex beer, just a little rough on the back of the throat early on. 2020 I might leave to bulk mature for a little longer or I might fruit it, to be decided.

I started by tasting each of them individually and writing a few notes, getting an idea in my head of how they “ranked” in the different characteristics for the initial couple of blend attempts, and then tweaked from there. Not sure if the photo will be clear enough to see this, but I basically started at equal parts of each and then tweaked from there.

Interesting process, I am planning to rack into a bottling bucket this weekend, then leave it for a couple of weeks just to make sure it doesn’t suddenly restart a fermentation, and then bottle.

 

[matt76]

Another update on my Brett aged porter;

I add this for reference as I struggled at the outset to get a clear idea what temp I should be doing this at - I appreciate my Tilt graphs are not necessarily that interesting for everyone else!

Having noticed it seemed to start fermenting due to the warm weather I moved the bucket into my brew fridge which was sitting idle, and set it to 24degC - you can see this in the red line to the right hand side of the graph.

As expected the gravity has contributed to drop steadily and it's currently down to 1.010-1.011 (maybe just starting to tail off).

No idea yet what the finished beer tastes like but based on this it definitely seems the brett.c wants to ferment at more like 24degC rather than 18-20degC.

 

[thegrantickle]

Does anyone have some useful information on calculating ABV in sour beers? If souring with lactobacillus, some carbohydrates will be metabolised and converted into lactic acid, thus changing the SG. How would you calculate abv in this case? for example, I'm brewing a lacto + brett beer just now. Should I take the SG after the lacto has done it's thing (48h) and immediately prior to pitching the yeast culture, and work the ABV off of that?

 

[dad_of_jon]

I just measured before pitching. I don't know the gravity of lactic acid Vs wort and I suppose the concentration of lactic acid needs calculating possibly from the pH drop? But I'd theorise it wouldn't make much difference. Happy though for those with this knowledge to improve my understanding of this.

 

[matt76]

Update on my Brett aged Porter - since I've no prior experience with Brett, the question is should I package it yet?

(And should I keg or bottle? It's only 10L so not a major job to bottle)

My initial expectation at the outset was that I'd age it for 3-6 months. So far it's been 12 weeks, so about 3 months.

Initially it didn't do much (at room temp!) until the weather got warmer. Since then I've held it in a fermentation fridge at 24degC and over a month or fermented down. For the last two weeks is been steady at 1.008-1.009.

So do you reckon I can go ahead and package or do I need to leave it longer?

My gut feeling from normal saccharomyces brewing is to go ahead and package, but maybe the flavours will continue to develop as it ages further???

Cheers,

Matt

 

[Sadfield]

For me, 1.008 would still be too high for bottling, and I'd be looking at stability over a time frame of many weeks rather than days. My gut feeling is that 1.022 was a high finish for M36, so most of the drop in gravity, since pitching the brett, is saccharomyces activity aided by the brett. I'd expect it to finish below 1.005. Historically, Porters would have been aged for 6 months or more. However, if you are happy with how it tastes now, you could research into killing the brett with potassium sulphate metabisulfite.

 

[matt76]

For me, 1.008 would still be too high for bottling, and I'd be looking at stability over a time frame of many weeks rather than days. My gut feeling is that 1.022 was a high finish for M36, so most of the drop in gravity, since pitching the brett, is saccharomyces activity aided by the brett. I'd expect it to finish below 1.005. Historically, Porters would have been aged for 6 months or more. However, if you are happy with how it tastes now, you could research into killing the brett with potassium sulphate metabisulfite.

Thanks for this @Sadfield , I'll take your advice and leave it be for now I haven't actually tasted it at all yet, so I'll just have to wait and see.

Re. the "high" finishing gravity with M36 - it was actually 1.020 by hydrometer (which I take as the gold reference standard as Tilt's can be a bit noisy). That is absolutely bang on what I expect having made this Porter a few times with M36, and also similar to what I see with my Stouts and BIPAs. I think it's simply a question of low-ish strength beer (4% ABV) => not so many fermentables / high proportion of unfermentables => expect a high-ish FG.

And now I write that, I've suddenly wondered if the hydrometer gravity might be a point or two lower than the 1.008 "Tilt" gravity...

But what I was going to say is, I wonder if your reasoned/expected 1.005 FG or thereabouts could actually be a point or two higher considering all the unfermentables in this beer.

I had a read through some more Milk The Funk - it appears for B. Claussenii we should be looking at high 20's, maybe even up to 30-32degC fermentation temperature! With this in mind I've banged it up a few more degrees, from 24 to 28degC - so let's give it a few more weeks and see where we're at

 

[Sadfield]

But what I was going to say is, I wonder if your reasoned/expected 1.005 FG or thereabouts could actually be a point or two higher considering all the unfermentables in this beer.

There's very little unfermentables now you've invited brett to the party. Bettanomyces can consume dextins and most wort sugars, lactose and sometimes the sugars found in wood. Further to that they can excrete amylase enzymes that cleave those unfermentables into fermentables for saccharomyces.

 

[alefric LeHendz]

Started a bit of a mixed ferm secondary trial today, I've split a packet of 5112 Brett brux across an Imperial stout (1.021 - Skare) and a "Orval inspired" pale ale (1.010 - lallemand abbaye). I've also added some boon dregs to a separate portion of the stout.

 

[dad_of_jon]

So I've been a bit hasty this time....

26/05/2022
Face off 2 - sour lacto boon - brew73 - green cap
3 kg richies extra light dme
650g golden syrup
used clear liquid from greek yogurt and dregs from boon mariage parfait 2017
20.5 litres
1.066 og - ph6
06/06/2022
1.050 - ph4 - beer was ropey

Compared with....

13/07/2018
Face off - sour lacto boon - brew43 - green cap
3 kg richies extra light dme
500g DWE
450g golden syrup
used clear liquid from greek yogurt and dregs from boon mariage parfait
1.067 og ph6
01/08/2018 - 1.035 - ph4
19/08/2018 - 1.012 - ph4
did not prime - bottled at 1.012
7.22%

I saw the airlock equalize so thought i'd bottle as it has been 10 days. However sample was 'ropey' thick , viscous snot like. So no doubt my gravity reading would be wrong. After drawing the sample off and having moved the fv for bottling, the airlock started up bubbling again. I'm confident the beer will be fine just gutted that 2 hours of prepping the bottling space etc are down the pan because I was too keen to get it bottled. The ropiness will disappear after aging. I'll probably this speed this brew up at the expense of sourness with a packet of yeast as I need to ditch the fermenter used for the sour for space for other stuff whilst redecorating. I still have another fermenter courtesy of using a bottling bucket setup in the past. I don't want to miss brewing a kviek when Swansea has it's 3 day heatwave this year and I can only get away with that if the other FV has gone.

How much of my 'sacrifice' will be acknowledged by Mrs DOJ I'm not sure