Throw Out Your Cubes

[RobW]

RobW: I provided a reference earlier in this thread that suggested that yeast is inactive in a solution of Aw <0.88. So we could assume that if the wort is able to support pitched yeast growth, then its Aw is likely somewhere around 0.88. BYO's article states that Cb's limit is Aw <0.93. I don't know how different (in reality) a 0.88 solution is from a 0.93 solution.

Kieran: I think we can say that if wort supports yeast growth its AW is greater than 0.88 but not how much.
I'd like to have a definitive value for the C. botulinum inhibition AW since the BYO article quotes 0.93 and the Wikipedia article says 0.97. That should be simple to get from a food tech book.

 

[argon]

Kieran: I think we can say that if wort supports yeast growth its AW is greater than 0.88 but not how much.
I'd like to have a definitive value for the C. botulinum inhibition AW since the BYO article quotes 0.93 and the Wikipedia article says 0.97. That should be simple to get from a food tech book.

Csiro also says .93

CSIRO Aw
We also know that Clostridium botulinum, the most dangerous food poisoning bacterium, is unable to grow at an aw of 0.93 and below.

The risk of food poisoning must be considered in low acid foods (pH > 4.5) with a water activity greater than 0.86 aw.

 

[kieran]

standard HDPE used in food safe containers (cubes) are very porous to oxygen, if I could quicly lay my hand on Wild Brews I could tell you how much .

Would be nice to see what the dissolved O2 concentration in wort was post-boil, then as a function of time in HDPE..

Got no idea what these HDPE tanks are: http://www.foodinnova.com/foodInnova/docu2/322.pdf
but they are porous to the tune of 2.15mg/L per month or 0.000215% w/v per month (this could be a different density HDPE I guess). But that is under 2% O2 which (from what I can tell) is the upper restricted limit for Cb spores to activate. I would've thought that the dissolved O2 in the post-boil wort going into a cube would've been much higher than that porous diffusion? Again, perhaps this is some 'special' wine aging HDPE plastic which isn't as permeable as the food safe container cubes. Would like to see what "Wild Brews" says.

 

[RobW]

Just found this (http://www.nelfood.com/help/library/nelfood-kb02.pdf):

C. botulinum AW values

Type A 0.95 Type B 0.94

Type E 0.97

These seem to be the 3 common human pathogenic strains - it appears that an AW below 0.97 would inhibit them all.

It also says this value is obtaind using salt and may vary for other solutes.

 

[stux]

Just found this (http://www.nelfood.com/help/library/nelfood-kb02.pdf):

C. botulinum AW values

Type A 0.95 Type B 0.94

Type E 0.97

These seem to be the 3 common human pathogenic strains - it appears that an AW below 0.97 would inhibit them all.

It also says this value is obtaind using salt and may vary for other solutes.

I'm reading that as a value below 0.94 would inhibit them all, ie the CSIRO's 0.93

What am I missing?

 

[RobW]

Yeah you're right - my bad.

 

[Feldon]

Found some evidence that Clostridium botulinum spores can survive the mashing proccess and can be present in the spent mash grain.

(and by extrapolation spores would also be present in the wort ?).


(Sourced from: S. Notermans et al, 'Safety and traceability of animal feeds', in Michele Lees (ed.), Food Authenticity and Traceability, Woodhead Publishing (Cambridge U.K., 2003), p.526 - available online via Google Books)

I'm thinking that a good practice when disposing of spent mash grain might be to spread it out on the ground so that the air can get to it. If dumped in a heap on the ground, the air in the core of the heap would soon be scavenged of oxygen by aerobic bacteria thereby creating an anaerobic (oxygen depleted) micro environment - the right conditions for the spores to become active and produce their toxin.

Maybe more important if you feed spent grain to the chooks. Whatever, Clostridium botulinum can already be present in your soil, but you don't want to encourage its further the colonisation around the brew shed and home.

 

[kieran]

Guys, I think this might help:

http://www.patentgenius.com/patent/6251461.html

Antimicrobial Activity of Hops Extract against Clostridium botulinum, Clostridium difficile and Helicobacter pylori.
E.A. JOHNSON, and G.J. HAAS, S. S. STEINER, INC. (NEW YORK, NY) (United States Patent 6,251,461, June, 2001)

The present invention relates to the discovery that hop extract is useful as an antibacterial agent against the dangerous pathogens Clostridium botulinum, Clostridium difficile, and Helicobacter pylori at levels below that at which a flavour from the acids contained therein is objectionable. More specifically, a process and associated product is described herein, comprising applying a solution of hop extract to a food, beverage or other medium so that the final concentration of hop ingredients is about 1 ppm or higher in order to inhibit the growth of Clostridium botulinum, Clostridium difficile, and/or Helicobacter pylori.

TFA has all the details... i can't access the patent figures.

I guess the take home is:

The hop extracts as used herein may comprise solvent extracted hops, or liquid CO2 or supercritical CO2 gas extracted hops. Particularly preferred are CO2 liquid or CO2 critical gas extracts. Generally, the hop extracts are added to a food product or other vehicle, in solution, to achieve at least about one part per million, by weight, of beta acids in the GI tract or stomach. Amounts less than about 1 ppm, by weight, beta acids, does not appear to provide protection against Clostridium botulinum and Clostridium difficile. The solution preferably contains about 5 ppm-100 ppm, by weight, of beta acids. The upper level is dictated by taste and solubility.

I suspect the patent is pitched at non-brewing food-stuff preservation..

Beta acids at the end of the boil in the wort, yeah.. lots and lots and lots? They aren't isomerised, and you can certainly smell them. Going by the patent's assertion that ~5ppm isn't detectable by the human nose, so if it smells hoppy, it must be over 5ppm.

If so, that might be it. How do you others read it?

 

[Nick JD]

Case closed.

 

[Dazza88]

When is IBU level detectable?

1 IBU provides sufficient protection?

 

[RobW]

Nice get. It would be good to see the original work they based the patent on.
I had a quick look but can't turn it up.

 

[stux]

The present invention relates to the discovery that hop extract is useful as an antibacterial agent against the dangerous pathogens Clostridium botulinum, Clostridium difficile, and Helicobacter pylori at levels below that at which a flavour from the acids contained therein is objectionable

So, if you can taste/smell hoppiness, no matter how minor, then its CB proof.

Oh Goody.

And now you know why by law in some states "Beer" *must* contain hops.

Always use hopped wort in your cubes

Now... just for the sake of argument... 5ppm as a minimum... is there a relationship between IBUs and ppm Beta Acids?

Of so, can we say that a beer of x IBUs is safe from botulism?

 

[Bongchitis]

You guys are pretty ******* awesome I must say!

 

[Dazza88]

Low hopped wort is the issue because some no chill beers may be hopped low, cubed and then later additions are added in a miniboil. I reckon 10 IBU is detectable at least but where is the IBU threshold.

 

[dr K]

Less than two weeks ago (and more than 350 posts ago) when I started this, what was to become an, opus:

I pose the question...what makes no chill fly?
## It causes no more reported cases of botulism that conventional chilling.

I followed with a series of points made about no-chill, none of which said no chill was bad, in fact quite the opposite, and proposed a simple, cheap , well proven method as an alternative. Now some may say I posted with cynical intent, but, frankly influenced somewhat by a recent re-reading of Umberto Eco's collection of essays "Travels in Hyperreality" I posted with semiotic intent.
But back to the point of the post: It would appear that after much discussion and even some brave poster putting his hand up to experiment with biotoxins (now that is silly),...drumroll... brewing of beer does not cause botulism!!!
All this science I don't understand. Observation I do understand, whilst all science is in the first instance based on observation, Science does not hold a monopoly on observation.
I hope that others have enjoyed this, and gained as much out of this as I have, but I think this threads time has come.
So long and thanks for all the AD Hope references.

K

 

[bradsbrew]

Less than two weeks ago (and more than 350 posts ago) when I started this, what was to become an, opus:
I followed with a series of points made about no-chill, none of which said no chill was bad, in fact quite the opposite, and proposed a simple, cheap , well proven method as an alternative. Now some may say I posted with cynical intent, but, frankly influenced somewhat by a recent re-reading of Umberto Eco's collection of essays "Travels in Hyperreality" I posted with semiotic intent.
But back to the point of the post: It would appear that after much discussion and even some brave poster putting his hand up to experiment with biotoxins (now that is silly),...drumroll... brewing of beer does not cause botulism!!!
All this science I don't understand. Observation I do understand, whilst all science is in the first instance based on observation, Science does not hold a monopoly on observation.
I hope that others have enjoyed this, and gained as much out of this as I have, but I think this threads time has come.
So long and thanks for all the AD Hope references.

K

And I took you as a credible poster. I guess you disproved that as well.

 

[Nick JD]

I'm going to change my name to Dr Nick. To gain credibility from the whole weetbix Ph.D thing.

 

[Cocko]

So, it seems you should have listened to me in the first place! :lol:

I no chill because its Rad.

Thus my beer is Rad.

Making me way Rad.

h34r:

Carry on..

 

[Bongchitis]

And I took you as a credible poster. I guess you disproved that as well.

Glad I'm not the only one that thought it was a bit off... sarcasm is the lowest form of wit etc etc

Dr K , You should go back to your hypereality..... they may be impressed by your superior intelect there.

 

[keifer33]

I'm going to change my name to Dr Nick. To gain credibility from the whole weetbix Ph.D thing.

I think you should Dr Nick,

The kneebone's connected to the... something. The something's connected to the... red thing. The red thing's connected to my wrist watch... Uh oh.