Kettle souring, can I do it?

[cmoewes]

Just wanted to see about some feedback from people to see if my brewing system will be able to handle the temperature control for an extended kettle souring, specifically maintaining the wort at ~ 100F for the time needed.

I have an old converted upright freezer that I use as a fermentation chamber out in my unheated garage. I have a small ceramic space heater with fan that puts our 750watts (or 1500 on full). Using this I have been able to maintain fermentation temperatures from 62-72 as required during even the coldest months in Minnesota (in January I had a Dubbel which I ramped up to 74 while the outside temperature was 15f).

Should I have any issue using my fermentation chamber to maintain the 100F needed for kettle souring now that temperatures are back into the 50s ?

 

[nvious23]

You could always sour in the mash tun it retains heat a lot better than the kettle.

 

[blizz81]

Test with water?

 

[unionrdr]

I read in the last issue of BYO about doing this with acidulated malt sprinkled on top of the mash. There were some other details though?

 

[inkman15]

I tried to do a sour mash in my tun for a Berliner Weiss and it was a disaster because I wasn't properly equipped to maintain the temperatures. Basically, i pitched some uncrushed grain on top of the mash and relied on a blanket and occasional space heater to keep the room warm. I clearly missed the mark and I ended up with a tun full of acetic acid smelling like a nice mix of vomit and Parmesan cheese.

If that wasn't bad enough, I started doing some Googling and found out about the possibility to create botulism in this kind of environment. I had tasted the wort the night before and being the insane hypochondriac that I am, I was terrified that I would contract botulism and also that I would have to trash all of my equipment. Botulism spores can't even be killed by boiling! Long story short, I'm fine but I dumped the whole batch. Also, it was very unlikely that I created botulism. But any chance is too much for me. Check out my thread if you want:

https://www.homebrewtalk.com/f127/sour-mash-newbie-hypochondriac-will-my-beer-kill-me-494006/

Not trying to dissuade you from your sour - but my point is that you should make sure you're able to maintain the correct temperatures. Because at minimum, you might end up with a batch of vomit beer and equipment that you'll need to thoroughly clean before thinking about reusing it.

 

[blizz81]

I believe the reasons people opt for kettle souring is because they're already using a vessel that they will then (after the period of souring) boil, so equipment "contamination" or cleaning worries are minimal and localized to the boil kettle only, which is probably what I would think the OP is looking for vs. a more traditional sour mash. Could be wrong though.

 

[inkman15]

I believe the reasons people opt for kettle souring is because they're already using a vessel that they will then (after the period of souring) boil, so equipment "contamination" or cleaning worries are minimal and localized to the boil kettle only, which is probably what I would think the OP is looking for vs. a more traditional sour mash. Could be wrong though.

Agreed - and that also applies to souring in the mash tun. Anything that touches the tun will ultimately be boiled afterwards, so there's no risk of contamination. People opt for kettle or mash tun souring since you'll never have lacto or wild yeast hitting your cold-side equipment.

 

[unionrdr]

True, but botulism can't be killed by boiling, only the enzyme, spores or that sort of thing it produces. Read about it once.

 

[Harry482]

For Berliners - I raise the temp of the wort to 180 just to kill any bad stuff (no boil), chill down to 100, then pitch lacto brevis. I have a space heater in my ferm chamber that keeps it at 100 for 24 hours - lacto bubbles like crazy at 100 degrees! I then chill to 68 and add a clean yeast to finish it off. I can usually bottle in 2 months and it's nice and tart.

 

[inkman15]

For Berliners - I raise the temp of the wort to 180 just to kill any bad stuff (no boil), chill down to 100, then pitch lacto brevis. I have a space heater in my ferm chamber that keeps it at 100 for 24 hours - lacto bubbles like crazy at 100 degrees! I then chill to 68 and add a clean yeast to finish it off. I can usually bottle in 2 months and it's nice and tart.

Good info but this assumes that you have at least one fermentation vessel dedicated to souring. If I tried to make a Berliner again, I'd probably go this route...

 

[blizz81]

Agreed - and that also applies to souring in the mash tun. Anything that touches the tun will ultimately be boiled afterwards, so there's no risk of contamination. People opt for kettle or mash tun souring since you'll never have lacto or wild yeast hitting your cold-side equipment.

I agree that it's all hot-side, but for some reason I have an illogical fear of getting my nicely-built RIMS + pump keggle involved in the bugging. I never use the silicone tubing outside of hot-side either so theoretically it would be ok but I would only consider boil kettle souring. Weird!

 

[Qhrumphf]

The botulinim bacteria might be killed by boiling, the toxin is denatured by boiling, but the spores can definitely survive boiling. However, in order to produce the toxin they require an anaerobic environment and a lot of time, neither of which occur during a sour mash (well, we try to make the environment anaerobic, but there's still some oxygen in the mash). The odds are so incredibly small that it's not really something to be worried about.

Now, the enteric Parmesan-Vomit stuff, that's a different story. What I learned was, in either case, to drop your pH to 4.5 before doing your souring, and to limit oxygen (purge with CO2 and/or cover with saran wrap). That'll inhibit the nasty stuff. I do sour mashes in my mash tun, do a normal conversion rest in the mid-150s at normal mash pH, pop in my immersion chiller directly into the mash, cool it to 110, drop the pH to 4.5 with lactic acid, pitch a handful of crushed base malt, cover with saran wrap (if I could purge with CO2 I would), and seal it up. I check the temp a couple times a day, and add boiling water as needed to keep the temp 100-110F. Once it's done, the mash still smells and looks funky, but once it's in the kettle to be boiled it's a super-clean lactic sourness with none of the nastiness.

 

[pdxal]

I've had luck maintaining temps with BIAB mash soured with raw malt, covered with foil to maintain anaerobic conditions, and setting the kettle on a heating pad on high to medium and covered with a cardboard box in a 58-60° basement. I don't see why you couldn't be successful with your approach. Higher temp+anaerobic=good, lower temp+/-O2=nasty.

 

[BGBC]

Good info but this assumes that you have at least one fermentation vessel dedicated to souring. If I tried to make a Berliner again, I'd probably go this route...

Not if you do it in the kettle, then boil after. The other advantage, as others noted, is that you can pitch a commercial lacto culture, instead of relying on raw grain for souring.

 

[unionrdr]

That was it, the toxin was denatured/destroyed by the boil. I just thought it was interesting how BYO talked about doing it by sprinkling some acidulated malt on top of the mash & proceeding as you stated.

 

[betarhoalphadelta]

Just wanted to see about some feedback from people to see if my brewing system will be able to handle the temperature control for an extended kettle souring, specifically maintaining the wort at ~ 100F for the time needed.

I have an old converted upright freezer that I use as a fermentation chamber out in my unheated garage. I have a small ceramic space heater with fan that puts our 750watts (or 1500 on full). Using this I have been able to maintain fermentation temperatures from 62-72 as required during even the coldest months in Minnesota (in January I had a Dubbel which I ramped up to 74 while the outside temperature was 15f).

Should I have any issue using my fermentation chamber to maintain the 100F needed for kettle souring now that temperatures are back into the 50s ?

Those sorts of space heaters probably have an automatic thermostat that won't let it go to 100 degrees.

Using a bulb like this in a closed and insulated refrigerator might do it, though. I've found that even much lower-wattage bulb easily gets a saison to ~90 degrees, so 150 watts of pure heat might be more than enough to get you over 100. Couple it with a Ranco or STC-1000 controller, and you're good to go.

 

[cmoewes]

True, but botulism can't be killed by boiling, only the enzyme, spores or that sort of thing it produces. Read about it once.

But botulism can't live below a ph of 4.2 and since you want to sour down into the 3.3 3.5 range that would take care of any botulism issues I would think. I that was a big concern, statistically we'd see a lot more cases of botulism in craft beer world which I think we would have heard more about?

 

[cmoewes]

Those sorts of space heaters probably have an automatic thermostat that won't let it go to 100 degrees.

Using a bulb like this in a closed and insulated refrigerator might do it, though. I've found that even much lower-wattage bulb easily gets a saison to ~90 degrees, so 150 watts of pure heat might be more than enough to get you over 100. Couple it with a Ranco or STC-1000 controller, and you're good to go.

Ahh, that's a good point. The thermostat on the heater may cut out before my stc1000 does. I actually only recently upgraded to the heater from the heat lamp in the paint can heater so might have to look at down grading back to that solution.

 

[cmoewes]

Just a follow up on the botulism (though certainly something I hadn't even thought of) based on CDC numbers about 150 cases a year, only 15% of them food sourced (the others are infant and wound related). So while something to think about, if it was a high risk issue from sour-mashing
I'd expect to see more cases.

And of those 150 cases annually only 3-5 cases result in death. Not that it's not worth noting, but crossing the street might be more risky

http://www.cdc.gov/nczved/divisions/dfbmd/diseases/botulism/#how_common

 

[cmoewes]

Another question, does using a pure culture (via smack pack) result it a better result with less potential for the vomit result? I've read that the bacteria that results in that smell doesn't like a low ph so either using a pure culture or growing one up with lower the risk of that issue.

 

[BGBC]

Another question, does using a pure culture (via smack pack) result it a better result with less potential for the vomit result? I've read that the bacteria that results in that smell doesn't like a low ph so either using a pure culture or growing one up with lower the risk of that issue.

You can get a good result with a grain Lacto, but it's more of a crap shoot than using a commercial culture since there's more on the grain than just Lacto. For my goses, I've made a Lacto starter with grain, to make sure that tasted good before pitching into a whole batch.

Planning on trying out WL's Brevis strain next to compare.

 

[Qhrumphf]

Another question, does using a pure culture (via smack pack) result it a better result with less potential for the vomit result? I've read that the bacteria that results in that smell doesn't like a low ph so either using a pure culture or growing one up with lower the risk of that issue.

You can get a good result with a grain Lacto, but it's more of a crap shoot than using a commercial culture since there's more on the grain than just Lacto. For my goses, I've made a Lacto starter with grain, to make sure that tasted good before pitching into a whole batch.

Planning on trying out WL's Brevis strain next to compare.

My club had Michael Tonsmiere speaking about sours last week. He mentioned that Lacto Brevis is seemingly more aggressive than other options, so that would be a good bet. He mentioned steering clear of WL Lacto Delbrueckki (which my own experience validates).

A lacto starter w/ grain would also be a good route to try.