Botulism & Canned kombucha "wort" (PH Control)

[Owly055]

I have done continuous brew for a long time now........... in fact at the moment I have 12 gallons of kombucha in brew buckets.

I recently ran across a thread where concern was expressed about canned wort used for cropping yeast............ The concern was that the PH was high enough that botulism definitely is a possible threat.

I honest had not thought of this before......... I make up a 2x concentrate of sweet tea, and pour it hot into growlers and seal them up. I draw off a gallon of kombucha, and add a growler of 2x sweet tea and a growler of water. It's quick, convenient, and easy.

Started reading about the PH of tea, and the PH where botulism thrives. Tea is not an optimal PH for botulism, but not low enough to be safe. Drop the PH just one point, and the whole equation changes. It only takes somewhere in the neighborhood of 1-2 tablespoons of distilled white vinegar per gallon to do this. That is per gallon of concentrate.........naturally this amount is half when diluted

I just ran a test, mixing that amount of vinegar in water, and tasting it alongside pure water. That there was a taste difference though very slight, could be observed when comparing the sample with pure water. Without a reference sample, it is not detectable to me.

Distilled White Vinegar is merely vinegar made from distilled grain alcohol......... it's not actually distilled. It consists of water and acetic acid, and nothing else. Acetic acid is the primary souring agent in kombucha, and I see no reason at all not to do this.

I did order a PH meter from Hong Kong (Ebay) for $8.21 including shipping....... I've needed one anyway, and it's good insurance.


H.W.

 

[kyt]

I wouldn't worry about it if you boiled the tea and the container. Standard canning procedure.

 

[Owly055]

I wouldn't worry about it if you boiled the tea and the container. Standard canning procedure.

Botulism spores are not killed at anything under 250F ............. Which is the reason we pressure can low acid foods like meats and vegetables. Hot water / boiling water, does not reach a high enough temp.

While the risk is fairly low in most cases, it does exist. Read the CDC report on home canning: http://www.cdc.gov/features/homecanning/

This is particularly a concern where honey is used, as honey is known for containing botulism........ It isn't a "don't worry, be happy" kind of thing at all.............

H.W.

 

[morticaixavier]

I pressure can my starter wort for brewing yeast for this very reason. I haven't started in on kombucha yet (although my wife had some this last weekend and would not like me to try it) but I imagine your idea would work just fine. Alternatly you could use lactic acid. I'm not sure of the amount but 88% lactic would require a lot less than ~6% acetic (vinegar) I don't know about taste thresholds though.

**EDIT**

also, when calculating how much a given acid addition will lower pH remember that you have to know the RA of the product you're adding it to.

 

[kyt]

This is particularly a concern where honey is used, as honey is known for containing botulism........ It isn't a "don't worry, be happy" kind of thing at all...........

OP didn't mention anything about honey and if it was that big of a concern for tea then you should totally avoid any packaged teas from the grocery or restaurants. Plenty of packaged tea is sold daily and I have not heard of any botulism outbreaks from it. Sounds like fear mongering to me.

 

[Owly055]

OP didn't mention anything about honey and if it was that big of a concern for tea then you should totally avoid any packaged teas from the grocery or restaurants. Plenty of packaged tea is sold daily and I have not heard of any botulism outbreaks from it. Sounds like fear mongering to me.

I strongly suggest that you read about botulism.......... You obviously have no idea what kind of environment it produces it's toxin in. The bacterial is not an infectious bacteria, but one that produces a poison. It thrives in an ANEROBIC environment with moisture, and where the PH is above 4.5. It's a spoilage bacteria, and is very frequently associated with honey. It spoils, often undetectably, foods that are canned and lack enough acidity, and are canned without reaching 250F. Teas are obviously NOT a place where botulism will reproduce, as they are dry, and you can bet that any bottled liquid products with a PH high enough to be a potential problem are heated well above 250F, as are ALL canned vegetables.

It is NOT a laughing matter or one to be dismissed lightly. I strongly suggest that you read the CDC report on botulism here: http://www.cdc.gov/nczved/divisions/dfbmd/diseases/botulism/ The toxin produced by this microbe is one of the most deadly known to mankind.

H.W.

 

[kyt]

In the United States, an average of 145 cases are reported each year.Of these, approximately 15% are foodborne, 65% are infant botulism, and 20% are wound.

So don't give honey to infants, duh.
Don't pour your tea, if it has dirt in it, in a wound, duh.
Now you're left with 15% of an average 145 reported cases. 145 * .15 = 21.75 average reported cases of botulism.

We'll round to 22 cases a year, I'm still NOT laughing about it, and I'm still NOT concerned about it. I read your article and all it did was convince me even more that I shouldn't be worried.
OP didn't mention anything about honey, or infants, or rubbing dirt in their wounds, or canning vegetables. Yes, the complications are severe, put so is having a piano dropped on your head; also not likely to happen.

Because the botulinum toxin is destroyed by high temperatures, persons who eat home-canned foods should consider boiling the food for 10 minutes before eating it to ensure safety.

So from what I can tell, this thread is mostly pointless fear mongering. I think I said that once before.
If you are so concerned about your method, then change it. Don't make all this tea in advance. If you absolutely have to put yourself at risk, boil your tea between 240°-250°F before putting it in proper canning equipment, not growlers. Then store it below 40°F.
You are aware of botulism; you chose your method. I'm not going to tell you that you're wrong, it sounds like a reasonable method to save some time, and I'm still not worried about it. I think you may be a little unduly paranoid. Rounding up, 22 people a year get sick from this. 22.