Infected beer - what is this?

Reads 13709 • Replies 39 • Started Sunday, January 3, 2010 4:08:51 AM CT

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flabeer
places 2 º 05:07 Mon 1/4/2010

Originally posted by TheBeerSommelier
Originally posted by wunderbier
Originally posted by TheBeerSommelier
Originally posted by OSLO
This looks like a by-product that survives the boil:
http://brewingtechniques.com/bmg/gudmestad.html

Another:
http://www.crc.dk/flab/fusarium.htm


The item in question that causes gushing is not the fungus itself, but a product of the fungus. It is developed during the mashing process.
If you throw a live rat into boiling wort and then leave it to ferment, you’ll end-up with an infected or rancid beer. Is it from the rat? Yes. Is the rat still living in the beer? No.

Read the articles!

Anyway the ORIGINAL QUESTION was about a particular beer gushing. Maybe it was simply over-primed!



Yes, that’s them! Should have linked some sources myself, I guess!

I really have no idea about the how’s of it. When the chemistry and biology gets this fine, I find it’s usually better to claim ignorance. I thought it was deoxynivalenol (DON) that caused the gushing as suggested in the BT article. Then I found these two articles. I feel there’s probably more about beer we don’t know than we do know.


Very true! This info really surprises me...it flies in the face of everything we learn about brewing - that something can actually pass through the boil, to subsequently infect the finished beer.

Definitely food for thought (pun intended).

 
sthlm
beers 790 º places 147 º 12:23 Mon 1/4/2010

Originally posted by flabeer
Originally posted by OSLO
This looks like a by-product that survives the boil:
http://brewingtechniques.com/bmg/gudmestad.html

Another:
http://www.crc.dk/flab/fusarium.htm

There are organisms which can survive the boil. Organisms can produce things that will survive the boil even if they do not. Boiling at normal atmospheric pressure does not kill everything.

The item in question that causes gushing is not the fungus itself, but a product of the fungus. It is developed during the mashing process.
If you throw a live rat into boiling wort and then leave it to ferment, you’ll end-up with an infected or rancid beer. Is it from the rat? Yes. Is the rat still living in the beer? No.

Read the articles!

I’ll post one more time because I finally located my copy of "Brewing; Science and Practice," by Dennis E. Briggs.

Flabeer, I mentioned that it was a by-product, but that doesn’t change anything. Organisms themselves can survive the boil during brewing as well, and an example of that is Bacillus coagulans. I’m sure there are plenty of others, but the point is that boiling at normal atmospheric pressure doesn’t necessarily kill everything or eliminate all problematic substances either. Anyways, here is the passage from the book I just mentioned which concerns the bottles gushing:

Malt and adjuncts derived from cereals present the greatest threat. Poor control of the steps involved in the manufacture of these ingredients can result in mould growth. Species of moulds from genera such as, Alternaria, Aspergillus, Cladosporium, Fusarium and Rhizopus have all been reported to produce adverse effects (Flannigan, 1999). Excessive mould growth produces many metabolites that can produce off-flavours and aromas in beers. Terms such as molasses, stale, burned and winey have all been used to describe the effects. In addition, changes in colour may also occur. The metabolites producing these effects also result in increased nitrogen levels in worts and beers. In extreme cases, beer hazes may be generated.

The most widely recognized defect ascribed to the growth of mould on malts is that of gushing. This phenomenon occurs in bottled beers where on broaching there is a sudden loss of carbon dioxide with concomitant uncontrolled foaming. Studies have demonstrated that culture filtrates of several moulds, especially Fusarium spp, were capable of inducing gushing when added to beers (Amaha et al., 1974; Kitabatake and Amaha, 1974). Small polypeptides have been isolated that are apparently responsible for the phenomenon. In one case a concentration as low as 0.05 ppm was sufficient to produce the effect (Kitabatake and Amaha, 1974). Moulds capable of producing gushing-inducing metabolites are commonly those that also produce mycotoxins. Indeed, some, but not all, mycotoxins have been shown to be capable of inducing gushing. More than 200 distinct mycotoxins have been isolated from various fungi. They appear to function as facilitators of fungal pathogenesis. The most common are the trichothecenes of which around 150 have been recognized. Chemically, they are tetracyclic sesquiterpenes, the most common being nivalenol, deoxynivalenol and T-2 toxin. All are potent inhibitors of protein synthesis and possibly they disrupt membrane function. Trichothecenes are heat stable and therefore capable of surviving through the wort boil. They are toxic to humans and animals. Purely from a brewing standpoint, if present at high concentration they inhibit yeast growth. It has been suggested that they could in some circumstances be a cause of sticking fermentation (Boeira et al., 1999a, b).

 
Cobra
beers 1100 º places 24 º 13:40 Mon 1/4/2010

Much as I hate to get embroiled in this argument, nonetheless, I will do so. For the sake of argument when making homebrew, boiling will kill off most of the nasties associated with those that cause human disease. This is a historical fact.

BUT, nothing kills BSE which is Bovine spongiform encephalopathy.
(AKA) Mad Cow Disease. It is remotely possible that BSE could be present in small amounts of grain, which cows are famous for trampling thru, and shitting out as they make their way thru a field of grain. (Corn included.)

So, it is remotely possibly to contract Creutzfeldt–Jakob disease, it’s not very likely. As for Aspergillus, it is more likely you could contract this thru poor sanitation methods, rather than any chance encounter. Aspergillus will produce a definite souring in the beer, namely because of it’s ability to produce Citric acid.

Bottom line: sanitize everything, change your sanitizers, make a starter everytime, and you’ll be OK for the most part.
Clorox is a good, cheap sanitizer, but it requires rinsing.
Iodophor is an excellent sanitizer, given that it’s used in proper dilutions.
Hope this helps.

 
Davinci
beers 295 º places 10 º 13:51 Mon 1/4/2010

Besides the fact that some bacteria may survive the boiling process another real threat is malt dust in the air which can contaminate wort and/or fermenting beer post boil. While it is true that most modern facilities do their milling in a seperate and enclosed area, many older breweries do not. In this case the infected malt dust can find it’s way into fermenters and other tanks.

As far as infected malt effecting malt pre-boil. I have heard that there were some problems in certain Belgian breweries using an infected batch of Dingemans malt leading to way overcarbonated bottles.

 
whaleman
beers 2178 º places 25 º 13:59 Mon 1/4/2010

Originally posted by Cobra

BUT, nothing kills BSE which is Bovine spongiform encephalopathy.
(AKA) Mad Cow Disease.



True, you cannot kill something that was never alive to begin with. BSE is caused by a prion (a mis-folded protein).


 
flabeer
places 2 º 21:34 Mon 1/4/2010

Originally posted by Davinci
As far as infected malt effecting malt pre-boil. I have heard that there were some problems in certain Belgian breweries using an infected batch of Dingemans malt leading to way overcarbonated bottles.



Ouch!

There is another problem with health and beer. If grain isnt dried quickly some fungis can produce toxins like aflatoxin and ochratoxin. These are the most toxic toxins in the world, and they "survive" boiling. I was examining these toxins in food (and beer) when working for the danish food and health controls 15 years ago and we found indications of levels of ochratoxins in beer so high that if you drank 10 L pr. day you would get livercancer from the toxins quicker than the alcohol! Later controls showed lower concentrations but still. To show that this is a real problem Carlsberg examined the same batch as we did in case we found something. (As I remember Carlsberg levels where very low).
And by the way: Most contaminated beers are contaminated in the bottle proces not from the basic grain. All patogene bacteria can not survice in numbers that can cause sickness because of hopps and alcohol levels. But some yeast can, but they are not very patogene.

 
iowaherkeye
beers 2703 º places 29 º 03:09 Tue 1/5/2010

Ummm. Doesn’t anyone (Matt) remember science class? With boiling water, only sanitation at 212 degrees can occur.

To kill all microbes you need an autoclave or pressure cooker at 250 degrees for at least 15 minutes, or 273 degrees for at least 3 minutes. I’d link but I’ve been posting from my phone the last 8 weeks.

There is also radiation, chemical, and filtration sterilization. Simply boiling water doesn’t kill prions or fungal spores, though, after 15 minutes it will kill most vegetative spores and inactive viruses.

Joey

 
cheap
beers 7474 º places 281 º 09:44 Tue 1/5/2010

OK, this is all very interesting but lets get back to the original question; how can a rookie, like myself, tell if a beer is infected?

Especially since some of the attributes described below are actually somewhat desirable in a beer. I’m sure I have tasted a few beers that were actually infected but didn’t know better.

I personally like sour or funky and would rate a beer that has these attributes higher if I didn’t know what the beer was supposed to taste, smell or look like. Quite often I only get one sample bottle so I wouldn’t have anything to compare to.

One good example would be the Hanssens Cassis I recently tasted. It had some attributes of burnt rubber but I wasn’t sure if it was supposed to have that.



Originally posted by wunderbier
"horsey" aromas, "barnyard" aromas, phenols, vegetable aromas, or esters. Other signs tend to be haze/turbidity, elevated carbonation levels, ropey appearance, dryness (lack of sweetness), or dull flavors.