Yeast Starter problem; maybe a solution?

[Brooothru]

So, I've been brewing for quite a few years. I can't remember the time I didn't use a starter yeast (1~2 liters, depending on style). I've always started the brew season by making a 3-5 gallon batch of dedicated wort, comprised of pale, neutral, unhopped beer. After the boil it goes into 1 quart sterilized Mason jars with lids followed immediately by a bath in a 10 psi/250F pressure cooker/canner for :20 mins to kill any and all nasties, including possible botulism and other pathogens. I have never had any issues with start-ahead starter wort prepared this way and feel it is shelf stable and safe to use for 1+ years.

Here's my dilemma. My pressure cooker is aluminum (non-conductive). Last year we replaced our electric stovetop with an induction stovetop which requires a conductive pot or pan if it's going to work. I can't use the aluminum pot on a banjo burner because it would melt, or at least deform and weaken, which would be extremely dangerous for a pressure cooker.

Here's what I'm thinking of doing. Use my stainless boil pot to prepared 3-5 gallons of starter wort from R.O. water, extra light DME, and a bit of yeast nutrients. After a 15-20 minute boil, transfer the uncooled wort to a sanitized and purged spare keg, leaving a nearly full keg of 200F 'starter wort' to chill outside in the winter cold (been below 0F/-18C here recently), with a cap of CO2 filling the void. I'd store the chilled keg in my beer fridge and use it as necessary throughout the year, pushing it out a liter or two at a time with CO2.

I'm certainly no microbiologist, but it seems to me that a :20 minute boil and a no-chill (ala: Australian "cube" method) transferred LoDO into a purged keg would result in a bacteria-free and pathogen-free pasteurized wort which would remain stable in a refrigerated environment for and extended period of time (maybe a year or more?).

I thought I'd run it up the flagpole to see if anyone saluted. I'm anxious to try this and would like to hear any comments, criticisms or critiques.

Thanks,

Brooo Brother

 

[day_trippr]

Why do you think you can't use an aluminum pressure cooker on a banjo burner with appropriate control?
I mean if you input a similar power level as found on a gas range what's the difference?
I can dial my bj14 burner down to where you can almost hold your hand over it...or high enough to burn to the bone....

Cheers!

 

[Brooothru]

Why do you think you can't use an aluminum pressure cooker on a banjo burner with appropriate control?
I mean if you input a similar power level as found on a gas range what's the difference?
I can dial my bj14 burner down to where you can almost hold your hand over it...or high enough to burn to the bone....

Cheers!

Over-abundance of caution I guess. The average BTU maximum output of a stovetop gas burner is ~7,000 (range of 3,000-12,000 BTU). The high level output of a banjo burner (Bayou Classic KAB) has an output up to 210,000 BTU! There's really no way of knowing just how hot the 'low' setting actually is. The focused flame heat at any given point, even at a low setting, could easily exceed a safe level for a cast aluminum pot, especially one that is expected to go through numerous cycles of heating/cooling while being subjected to the mechanical stresses of repeated pressurization cycles. I've had a career's worth of exposure to high pressure fluids from hydraulic fluid ~3,000 psi to high pressure steam ~1,200 psi, and even though 15 psi doesn't sound like much, it can send shrapnel flying at lethal velocities and pressures if a containment vessel fails.

That's probably the reason why the directions that came with the pressure cooker (yes, I still have them after all these years) specifically states NOT to use outdoor gas appliances (even grills) because the "excess heat stress can cause failure of the pressure cooker resulting in serious injury or death." Even my stainless steel conical fermenter is pressure limited to 2.5 psi. I'm told the 6 spring latches holding it together are designed to fail between 3-5 psi sending the domed steel lid flying and gallons of fermenting beer being ejected. Fluid dynamics and fluids under pressure are not to be trifled with.

I even start to get hinkey at putting more than 30 psi in a Corny keg, even though they're rated to 130 psi. There's no way of knowing how many cyclic stresses that reconditioned keg has undergone in its service life. I've seen the damage that can result from being cavalier with pressurized fluids. Bad ju-ju when things go south.

 

[day_trippr]

I think you're being overwhelmed by a specification for WOT instead of using your vision and common sense. Unless your regulator is total crap you can dial it down to where the flames are nearly out and work from there.

So do or do not, but fwiw I used to use a 24 quart aluminum pressure cooker on a Blichmann Floor Burner (bg14 with 0-10 psi regulator) as a steam generator to hold mash temperatures in my 10 gallon Rubbermaid MLT. Worked a treat until I got my 20 gallon system running...

Cheers!

 

[sibelman]

Here's my dilemma. My pressure cooker is aluminum (non-conductive). Last year we replaced our electric stovetop with an induction stovetop which requires a conductive pot or pan if it's going to work.
Brooo Brother

Broothru, you can keep using your aluminum pressure cooker (and any other non-induction pots you favor) with an induction disk. Not elegant, perhaps, but cheap and simple. Cheers.

 

[Brooothru]

Broothru, you can keep using your aluminum pressure cooker (and any other non-induction pots you favor) with an induction disk. Not elegant, perhaps, but cheap and simple. Cheers.

True, but there is a transference of heat from the induction disk that gets transmitted back into the stovetop. At high temperature settings for extended time, that heat can damage the cooktop. Induction disks work, but without underlying risk. There is no free lunch.

Obviously pressure cooking would require a high power setting for an extended period of time. It would work , but SWMBO would not be amused if I trashed her new induction range. And it would cut into my beer budget.

Brooo Brother

 

[sibelman]

True, but there is a transference of heat from the induction disk that gets transmitted back into the stovetop. At high temperature settings for extended time, that heat can damage the cooktop. Induction disks work, but without underlying risk. There is no free lunch.

Obviously pressure cooking would require a high power setting for an extended period of time. It would work , but SWMBO would not be amused if I trashed her new induction range. And it would cut into my beer budget.

Brooo Brother

I respect your wish to protect the cooktop -- my induction stove manual does warn against leaving "...pressure canners on high heat for an extended amount of time" and recommends alternating surface units rather than using the same burner all day. This concern would seem to apply pretty equally to induction cookware and aluminum-plus-disk. Some folks do pressure-cook on induction -- see this page. Best of luck finding a way to harmonize your concerns about stove, cooker, SWMBO, budget.

 

[Vale71]

Just get one of these, they're cheap and work fine with any material.
The answer to your question regarding whether your wort is safe to be stored for a long time after a standard boil is, "Absolutely not."

 

[Qhrumphf]

Boiling does not kill botulism.

And botulism grows in an anaerobic environment. Like LODO wort stored in a purged/sealed keg.

While re-boiling that wort immediately prior to use would denature any botulinum toxin (the actually dangerous part) that a) defeats the purpose of the whole exercise and b) doesn't speak to anything else, toxic, pathogenic, or otherwise that could grow/be formed in there.

Unfermented, unhopped wort is a breeding ground for bacteria. Lots of sugar, and a high enough pH that lots of pathogens can survive.

And since you've emphasized sanitize vs sterilize, you surely understand the difference.

Not worth the risk.

 

[micraftbeer]

I'm very interested if anyone can explain the science that makes unfermented started wort canned works but unfermented starter wort made and stored in the keg under pressure doesn't.

I'm not disputing that it won't work, I just have a curious mind.

 

[Qhrumphf]

I'm very interested if anyone can explain the science that makes unfermented started wort canned works but unfermented starter wort made and stored in the keg under pressure doesn't.

I'm not disputing that it won't work, I just have a curious mind.

If it's not sterilized (higher temp than simply boiling, done at home in a pressure cooker as outlined in the first post), canned wort isn't safe either.

If you could package wort in a keg under sterile conditions then it'd be fine, at least until you drew from it unless the line too was also sterile. So even then single use cans work better.

Remember, sanitized is not the same thing as sterile, and boiling sanitizes- it does not sterilize.

 

[Vale71]

I'm very interested if anyone can explain the science that makes unfermented started wort canned works but unfermented starter wort made and stored in the keg under pressure doesn't.

I'm not disputing that it won't work, I just have a curious mind.

Some microbes are able to create spores. Spores aren't killed at normal boiling temperature, hence the need for an autoclave to reach higher temperatures. Once the wort cools spores will find themselves in a nutrient-rich environmente and will develop into active bacteria again.

 

[IslandLizard]

I'm very interested if anyone can explain the science that makes unfermented started wort canned works but unfermented starter wort made and stored in the keg under pressure doesn't.

I'm not disputing that it won't work, I just have a curious mind.

The difference between pasteurized and sterilized.

 

[Qhrumphf]

Some microbes are able to create spores. Spores aren't killed at normal boiling temperature, hence the need for an autoclave to reach higher temperatures. Once the wort cools spores will find themselves in a nutrient-rich environmente and will develop into active bacteria again.

And in the case of botulism, neither the spores nor the bacteria are harmful in themselves. Its when those spores begin to grow as active bacteria in a higher pH (wort qualifies, beer pH is too acidic), and anaerobic environment, that they produce the botulinum toxin that is so dangerous.

This is why some foods don't need to be canned in a pressure cooker but some foods do.

It is worth pointing out in fairness that botulinum poisoning is exceptionally rare, and most cases aren't even foodborne. And to my knowledge there are zero reported beer-related cases.

But. Given that botulinum poisoning is quite easily fatal, that makes any preventable risk untenable in my opinion.

 

[Brooothru]

I agree with everything you say, and as a non-microbiologist I can't argue the science. The disconnect comes when you take into account the Australian "no chill" method of brewing where boiling wort is transferred into PTFE "cubes" and allowed to chill to pitching temperature absent any mechanical cooling. Often it is stored at ambient temperature unrefrigerated for days or even weeks (and reportedly sometimes months and even YEARS) before it's transferred to a fermenter and yeast gets pitched.

Aussies swear by the process, and apparently no Jonestown style mass extinctions have resulted. I can't explain it. Given its apparent popularity you'd expect at least some reports of botulism or major fermentations gone bad, though it seems not to be the case. Perhaps one of our friends 'Down Under can elaborate.

Brooo Brother

 

[Brooothru]

Boiling does not kill botulism.

And botulism grows in an anaerobic environment. Like LODO wort stored in a purged/sealed keg.

While re-boiling that wort immediately prior to use would denature any botulinum toxin (the actually dangerous part) that a) defeats the purpose of the whole exercise and b) doesn't speak to anything else, toxic, pathogenic, or otherwise that could grow/be formed in there.

Unfermented, unhopped wort is a breeding ground for bacteria. Lots of sugar, and a high enough pH that lots of pathogens can survive.

And since you've emphasized sanitize vs sterilize, you surely understand the difference.

Not worth the risk.

Exactly, which is the factoid I forgot to consider with my "boiling wort into sanitized keg" solution. As palm reached forehead (my "Duh" moment...) I remembered WHY I'd pressure-canned the wort to begin with: 2 bar pressure gives a boiling temperature of roughly 250F, which if held for 20-30 minutes will sterilize the wort, or at least render the population of pathogens sufficiently small enough to be safe for human consumption for a relatively long period of time. I knew better. I just forgot.

I'm just glad that I was smart enough to ask the braintrust here on the forum. Thanks, mates, for saving me from myself!

Brooo Brother

 

[Brooothru]

Just get one of these, they're cheap and work fine with any material.
The answer to your question regarding whether your wort is safe to be stored for a long time after a standard boil is, "Absolutely not."

Absolutely correct. Now I remember why. Thanks for the knock "up the side o' my head".

 

[Soulshine2]

So, I've been brewing for quite a few years. I can't remember the time I didn't use a starter yeast (1~2 liters, depending on style). I've always started the brew season by making a 3-5 gallon batch of dedicated wort, comprised of pale, neutral, unhopped beer. After the boil it goes into 1 quart sterilized Mason jars with lids followed immediately by a bath in a 10 psi/250F pressure cooker/canner for :20 mins to kill any and all nasties, including possible botulism and other pathogens. I have never had any issues with start-ahead starter wort prepared this way and feel it is shelf stable and safe to use for 1+ years.

Here's my dilemma. My pressure cooker is aluminum (non-conductive). Last year we replaced our electric stovetop with an induction stovetop which requires a conductive pot or pan if it's going to work. I can't use the aluminum pot on a banjo burner because it would melt, or at least deform and weaken, which would be extremely dangerous for a pressure cooker.

Here's what I'm thinking of doing. Use my stainless boil pot to prepared 3-5 gallons of starter wort from R.O. water, extra light DME, and a bit of yeast nutrients. After a 15-20 minute boil, transfer the uncooled wort to a sanitized and purged spare keg, leaving a nearly full keg of 200F 'starter wort' to chill outside in the winter cold (been below 0F/-18C here recently), with a cap of CO2 filling the void. I'd store the chilled keg in my beer fridge and use it as necessary throughout the year, pushing it out a liter or two at a time with CO2.

I'm certainly no microbiologist, but it seems to me that a :20 minute boil and a no-chill (ala: Australian "cube" method) transferred LoDO into a purged keg would result in a bacteria-free and pathogen-free pasteurized wort which would remain stable in a refrigerated environment for and extended period of time (maybe a year or more?).

I thought I'd run it up the flagpole to see if anyone saluted. I'm anxious to try this and would like to hear any comments, criticisms or critiques.

Thanks,

Brooo Brother

water reaches its boiling point at 212*F ,it doesnt care if its in aluminum or stainless steel or pyrex . aluminum melts at 1220.58*F ...Even if you heated the aluminum pot empty (which you wouldn't) ,you're not going to melt it with a banjo burner.