Souring in the kettle

[Woolsocks]

Has anyone had success producing "sour" beer styles by a process similar to this:

1. Run off wort into the kettle
2. Boil 15 minutes to sterilize
3. Cool to "critter" temperature - 100°F or so
4. Pitch "critters" such as lactobacillus directly into the kettle
5. let them sour your wort for a couple days
6. Boil and hop your wort as you normally would (kill off critters in the process)
7. Ferment with yeast strain of your choice

Main advantages would be 1) no long waits for critters to sour hopped/alcoholic beer and 2) very low risk of contaminating your brewing equipment with critters
Disadvantages would be 1) possible darkening of your wort as it sits in the kettle and 2) you tie up your kettle for that long of a time

[MikeRoy]

Yes, but with a few different steps/approaches.



Run off wort into the kettle
Yes.
Boil 15 minutes to sterilize
No. I don't see the need to boil and sterilize prior to contamination.
Cool to "critter" temperature - 100°F or so
I send through the heat exchanger back to the mash tun down to 120 F and turn my steam jacket to hold temp( the mash tun can seal under low pressure while my kettle does not)
Pitch "critters" such as lactobacillus directly into the kettle
I don't pitch critters, though I've known brewers who pitch lacto, I simply mill in Pils malt and flood with inert gas
let them sour your wort for a couple days
exactly, though taking some ph samples is always a good idea
Boil and hop your wort as you normally would (kill off critters in the process)Yes, process as normal
Ferment with yeast strain of your choice
Yes


As far as tying up your equipment you could sour in your fermenter and then pump back to brew house but then you obviously have some concerns and cleaning to do. I simply schedule a mash in on say a Sat or Sun and then finish the beer at the start of the week, you'll just need to tinker with your production schedule.

[Smuttynose]

Kettle Sour

We kettle sour periodically. Works great. We don't bother to boil before adding the lacto culture. It doesn't affect the flavor at all. Once we run off we add a double pitch of bugs. Our kettle has blades that keep the wort and bugs circulating so within 24 hours we're below 3.5 pH. When we didn't use the blades it took about two days. We then boil it and ferment with yeast. I wouldn't say it's better or worse than other souring methods, just different. And you don't infect your other beers.



Cheers,


dave

[lhall]

Dave @ Smuttynose -

Did the lower pH of 3.5 affect the subsequent fermentation at all?

[BenBailey]

We kettle sour periodically. Works great. We don't bother to boil before adding the lacto culture. It doesn't affect the flavor at all. Once we run off we add a double pitch of bugs. Our kettle has blades that keep the wort and bugs circulating so within 24 hours we're below 3.5 pH....
Cheers,
dave

Dave, What do you mean by a "double pitch"? We were about to use the same method to sour a beer, but I am not sure how much lact. delbruckii to add. We usually grow up our yeast stock in the lab from slants, and we were planning on doing the same for the lacto, but I don't have any data on what kind of cell count to add.
Thanks,

Ben

[Woolsocks]

What are some other caveats? Does the wort start to oxidize and darken? Our kettle and mash tun don't seal — does that matter? How do we keep acetobacter activity to a dull roar? The only way we have to stir our kettle is turning on the whirlpool function — good idea?

[Justin Viale]

I did a Berliner Weisse recently with just about the same procedure that you outlined. We did not boil after runoff to sterilize. We chilled through the HX back into the kettle and we used a pitchable strain of L. brevis instead of grain which I've always assumed gives mostly or all L. debruckii. We set the kettle temp at around 115 and it soured overnight, it reached a pH of 3.5 within 12 hours, I wanted it lower and it took about 18 hours to reach 3.25 or so.

From there, we didn't even boil the wort again, we brought it up to 180F and held it for 30 minutes and added the hops at this temp. Chilled into a fermenter and pitched 1056.

If you have concerns about acetobactor or other aerobic bacteria, you can drop a CO2 line into the kettle and keep a gas blanket on it. We found that this wasn't really necessary, that just leaving the wort undisturbed and closing up the kettle doors (ours do not seal) did not have any negative effects.

To answer Linus's question, at least our one experience was that the fermentation seemed to finish slightly higher than expected. Whether or not that was from the lower pH, I don't now.

[Smuttynose]

Sorry about the delay responding. The low pH didn't affect fermentation with a Belgian yeast at all. It went normally. I would think most yeast strains would work well.

Double pitching meant that we added twice as much lacto per volume. So we had 30 bbls of wort in the kettle and bought a 60 bbl pitch.

We've hooked up CO2 through the spray ball to help with acetobacter and other non desirable bugs, however with the amount of lacto added I doubt anything else can compete. There wasn't any oxidation or darkening issues. It's real similar to fermentation in an open fermenter.


Hope this helps,

dave

[Woolsocks]

in the middle of the process - help!

We're doing more-or-less the process outlined above. Our wort is stronger than your typical berliner-weisse - about 16°P. It's been over 24 hours and our pH has only dropped from just over 4.9 to just under 4.8 - not the expected result. Wort has been around 120°F and while we're here during the day, we've been slowly running the whirlpool to keep the critters moving.

I'm planning to dilute with water to hopefully take some pressure off the critters. Any other ideas to speed this up?

[Woolsocks]

whew

I diluted my wort some and left it for another night. In the morning, pH had dropped to 3.7 and there was a significant tart flavor. On to the boil....

[Mattblock]

Cheesey aroma

So I have kettle soured overnight quite a few times and generally it works like a charm. I follow the exact same regimen that has been described on this thread and yet two different times with two different beers I have come back the next morning to a very pungent cheeselike aroma. I have had no success in scrubbing these flavors or aromas from the beer after trying boiling, brettanomyces and quite a bit of time. I am curious if anyone else has had the occur to them, or knows the source of the off-flavors. Or possibly something that would be successful in removing it from a finished product.

Matt

[AnthonyB]

Are you blanketing with CO2 or something else to discourage O2 pickup? Are you pitching a pure culture or doing a sour mash to get the bugs?

[MatthewsBrew_]

Bringing this thread back from the grave. Does anybody else add phosphoric or lactic acid to the kettle when souring to decrease the amount if time it takes to get to a ph below 4.0? I was told that lowering the ph will help reduce the chance of infection.