# Sourdough starter -> kettle sour



## fdsaasdf (28/9/16)

Hi all,

I am very keen to try a kettle sour to see if I can make something drinkable, and as regular sourdough baker I am hoping to find out if the starter would be a viable source of lactobacillus for this purpose.

I have had a search and read a couple of sour beer articles this evening but am unable to find another example of this. Has anyone here tried to do this or could offer an opinion on the likelihood of success?


Cheers


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## peteru (29/9/16)

If you want a good source of lactobacillus, try youghurt or a live sauerkraut.

Mind you, I can't offer advice on whether that will actually produce pleasant results for beer making.


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## indica86 (29/9/16)

I don't see why it would not work.
I have made two using a yoghurt culture. Both very nice.


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## jbaker9 (29/9/16)

What is the benefit of using yoghurt culture or sourdough over a couple of handfuls of grain? I did this and it worked great.


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## indica86 (29/9/16)

My aim is to have something I can repeat. A measured amount of a known quantity is the key for that.


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## damoninja (29/9/16)

jbaker9 said:


> What is the benefit of using yoghurt culture or sourdough over a couple of handfuls of grain? I did this and it worked great.


As stated above, repeatability. In addition you don't know if you're just getting _good_ baddies or _bad_ baddies from grain. 

The thing is with kettle sours is yes they'll sour but you won't get some holy grail of sour beers, a berliner weiss or simple refreshing sour though it'll manage. 

Yoghurt and sourdough are less likely to get as sour as single strains that are better at coping with lower pH, yoghurt will still likely get to pH 3.1-3.4 which is moderately to fairly tart. 

Few other things to note
1. Use unhopped wort
2. Sanitation is even more critical
3. Keep your temps high for faster souring


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## Lyrebird_Cycles (29/9/16)

Sourdough is generally not a single strain but an entire microbial ecology of its own; one study at Sydney Uni found 43 species of LAB and about half that many yeasts. Some of the LAB are more acid tolerant than others, the Sydney study mentions _pediococci_ which are a known player in wine spoilage at pHs in the low 3s.

I say go for it.


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## pvan340 (29/9/16)

Have you any way of keeping your kettle warm enough? I sour in cubes in my ferment fridge with the temp controller set at 44 degrees. It's amazing how two cubes will keep the temp stable inside a well insulated fridge. You can also keep oxygen to the minimum, which is difficult in a kettle, though it can be done. Oxygen and lactobacillus usually means horrible smells ( I know from experience with kettle souring using grain and what turned out to be an ineffectual oxygen barrier).


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## damoninja (29/9/16)

pvan340 said:


> Have you any way of keeping your kettle warm enough? I sour in cubes in my ferment fridge with the temp controller set at 44 degrees. It's amazing how two cubes will keep the temp stable inside a well insulated fridge. You can also keep oxygen to the minimum, which is difficult in a kettle, though it can be done. Oxygen and lactobacillus usually means horrible smells ( I know from experience with kettle souring using grain and what turned out to be an ineffectual oxygen barrier).


I don't sour in my kettle for that reason, I can't keep the temp. I place mine in a FV and place in my fermentation chamber with a water bed heater and set it to the required temp. The oxygen in the top has not worried me before, I just transfer it carefully so I don't flood the liquid with O2, if you add oxygen you're more likely to get wild yeast than anything else. 

44 is pretty high was that with a yoghurt strain? Suggestions are that most strains prefer around 30C some up to 45C. 

For sourdough I'd go middle of the road and go for 35 to keep as many strains as possible happy. 



Lyrebird_Cycles said:


> Sourdough is generally not a single strain but an entire microbial ecology of its own; one study at Sydney Uni found 43 species of LAB and about half that many yeasts. Some of the LAB are more acid tolerant than others, the Sydney study mentions _pediococci_ which are a known player in wine spoilage at pHs in the low 3s.
> 
> I say go for it.


I suppose what I meant is - you don't know what you've got  but I do agree for sure, go for it!


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## fdsaasdf (29/9/16)

Great feedback, thanks everyone.

Yes, the point of using a sourdough starter is that I have a culture that I can keep using in an attempt to learn from the result and eventually repeat a process that I'm happy with.

I'm not sure exactly which varieties of lacto live in my sourdough starter but it's always very responsive to food and gives a sharp sourness so there's some varieties in there  

I shouldn't have any problems keeping temp as I was planning to wrap the kettle in my mashtun insulation and then sit it on a heat pad plugged into my stc-1000 in the fermenting fridge.

My plan at this stage is to use unhopped wort and then have plenty of late kettle hops in the boil. My better half doesn't really like sours but enjoyed 8wired's hoppy berliner so if I can use a decent crack at that to be the thin end of the wedge I just might have found a way to stop all my IPA disappearing...


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## jbaker9 (30/9/16)

I soured in my esky mash tun... threw a heat belt into it connected to a thermostat set at 40c. Worked a treat.


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## damoninja (30/9/16)

jbaker9 said:


> I soured in my esky mash tun...


Did you nuke it with bleach first? 




jbaker9 said:


> threw a heat belt into it connected to a thermostat set at 40c


Like, submerged it?


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## goatchop41 (4/10/16)

Just be careful of the sourdough starter around your (plastic) fermenters and other cold side equipment.
I swear that when I bottled a beer in the kitchen an hour or two after preparing the dough for a sourdough boule (and may not have cleaned up as well as I should have), it kicked off an infection that eventually spread to all of my plastic equipment and I ended up having to throw it all out (tried acidified bleach on two of them along with my bottling equipment and it still didn't get rid of it.)

I may just be making a false connection, but I wouldn't be surprised if some of the wild yeast from the sourdough is what did it, which would explain why my starsan didn't kill it (effective against bacteria but not yeasts, as far as I've read)


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## hirschb (4/10/16)

Some weird advice on the follow up posts!
The short answer is NO. Sourdough has both lacto and yeasts. The yeasts will chew through your sugars and produce alcohol... which means that you are not making a kettle sour. The point of a kettle sour is to produce acid with lacto (in a controlled way) without producing alcohol, and then once the desired acidity is reached, boil the wort to kill off the lacto, cool, and then ferment with a yeast strain.
You can make a mixed fermentation sour beer with sourdough starter. Go here for info: https://thebeerminimum.wordpress.com/2015/05/21/98-sourdough-saison/
For alternate lacto sources, go here (and MTF should really be your first stop resource for any sour beer info): http://www.milkthefunk.com/wiki/Alternative_Bacteria_Sources


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## hirschb (4/10/16)

Just to clear up some stuff:

"Yoghurt and sourdough are less likely to get as sour as single strains that are better at coping with lower pH, yoghurt will still likely get to pH 3.1-3.4 which is moderately to fairly tart"
RE: 3.1 is extremely sour, 3.4 is sour-moderately tart. Also keep in mind that the perception of sourness and pH are related, but not perfectly, so you can have a lower pH beer that seems less sour than a higher pH beer. Also, pH is measured on a log scale, so a 3.0 beer is ten times more acidic than a 4.0 beer, and 3.1-3.4 is a huge range.
Single strain lactos vary widely in their ability to reach a final pH. Some can hit 3.1, others cannot.

"Have you any way of keeping your kettle warm enough?"
RE: This depends on the lacto strain. Some strains are almost inactive at normal fermentation temps, while other do great at 20+.

"Use unhopped wort"
RE: As a general rule, yes, but this varies by lacto strain. Some are full-on hop tolerant, others need IBU's less than 3-5, and others are crap with any amount of hops.

"Oxygen and lactobacillus usually means horrible smells"
RE: Nope, not true. Oxygen and various bacterias produce Butyric acid (vomit smell), Indole (fecal aroma), and Isovolaric (foot smell). If you use grain as a lacto source, you will often get the various microbes that produce these odors with it. To combat that, grain souring needs to be done in an oxygen free environment, and (hopefully) with some pre-acidification (down to about 4.3pH) to prevent these nasties from growing/replicating. If you use a pure lacto culture, you will not get off-flavors/aromas unless you get an infection.


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## indica86 (4/10/16)

hirschb said:


> Sourdough has both lacto and yeasts.



Yeah right, brain fade there from me.


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## fdsaasdf (4/10/16)

hirschb said:


> Some weird advice on the follow up posts!
> The short answer is NO. Sourdough has both lacto and yeasts. The yeasts will chew through your sugars and produce alcohol... which means that you are not making a kettle sour. The point of a kettle sour is to produce acid with lacto (in a controlled way) without producing alcohol, and then once the desired acidity is reached, boil the wort to kill off the lacto, cool, and then ferment with a yeast strain.
> You can make a mixed fermentation sour beer with sourdough starter. Go here for info: https://thebeerminimum.wordpress.com/2015/05/21/98-sourdough-saison/
> For alternate lacto sources, go here (and MTF should really be your first stop resource for any sour beer info): http://www.milkthefunk.com/wiki/Alternative_Bacteria_Sources


Thanks very much, appreciate the detailed answers. Plenty of food for thought.


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## damoninja (4/10/16)

I wrote some stuff in response and lost it not cbf, but yeah not going to make a kettle sour I didn't realise just how yeasty it was but I might exbeeriment with it myself FTW


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## hirschb (5/10/16)

damoninja said:


> I wrote some stuff in response and lost it not cbf, but yeah not going to make a kettle sour I didn't realise just how yeasty it was but I might exbeeriment with it myself FTW


Yeah, you can always try it, worst case scenario, you dump a batch. The best sour brewers often say that the biggest mistake new sour beer brewers make is that they are afraid to dump a batch if it's crap. Scratch brewing in Illinois does a lot of cross-contaminated sourdough/beers, and they are delicious!


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## damoninja (5/10/16)

hirschb said:


> Yeah, you can always try it, worst case scenario, you dump a batch. The best sour brewers often say that the biggest mistake new sour beer brewers make is that they are afraid to dump a batch if it's crap. Scratch brewing in Illinois does a lot of cross-contaminated sourdough/beers, and they are delicious!


I'm never afraid to dump something if it's shit  that's only happened a few times but they were spontaneous ferments (well inoculated with **** knows what from misc stuff like flowers). I'd just make a small 3L thing to begin with see how it turns out, if that works that good and I really want to make a whole batch then it'll be the starter for it.


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## fdsaasdf (7/10/16)

damoninja said:


> I'd just make a small 3L thing to begin with see how it turns out, if that works that good and I really want to make a whole batch then it'll be the starter for it.


That's close to what I had in mind, thinking a 2L batch that I can ferment and then condition in a swingtop growler to save my plastic fermenter...


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