Infection

[kurtz]

I have made reference to infection in two previous posts this evening so thought it worthwhile to split this out.
One post was in response to a white film on top of the beer the other a response to the remarkable number of brewers who have never had an infection.
At the risk of repeating myself...if you have never had an infection how do you know what an infection is.
Infections most commonly are fairly low level but certainly detectable to the palate.
As most brewers clean their fermentor fairly well it is unlikely that an infection will arise from a dirty fermentor directly.
Lets have look at the A-Z of infection
Acetaldehyde..that Granny Smith apple smell not an infection as such as it is a by product of the fermentation process but then is then converted to alcohol. It can be product of oxidation of the finished beer where ethanol is actually converted to acetaldehyde or worse or it can be a result of infection by acetobacter.
Astringency, generally created by tannins from the grain but can be put down to tannins produced by our friend acetobacter or wild yeast.
Diacetyl..think butterscotch or movie theatre pop corn ! Again most commonly a by product of fermentation (I believe that English Bitters actually benefit from low levels) but can also be caused by lacto bacteria.
DMS..open up a can of corn..you will know what I mean, its in the malted barley but should be driven off during the boil, if you are using a kit the extact will have no DMS but can be caused by wild yeast or bacteria.
Phenolic..the big one..think band aids, think first aid stuff. pooh..bacteria and wild yeast cause this and it is the most comon infection from poor saniatation.
Sour..just the go in a Lambic or Flemish beer or a Berliner Weisse (at low levels) but not to good in your Becks clone..heaps of reasons. Lactobacillus, our friend Acetobacter, Pediacoccus, Brettanomyce, wild yeast in general.
Sulphury, again most likely from some sort of bacterial contamination.
Zymomonas Mobilus..a very effective fermentor/ producer of ethanol but total shit to beer.

As I pointed out earlier Oxygen is not your friend (except of course in the initial yaest growth stage) and those HDPE plastic buckets just suck it in.
Oxygen is what promotes acetobacter which can, depending on the level of infection cause all sorts of aromas and flavors.

Kurtz

[Dogger Dan]

Believe me son, I haven't had an infection and I do know what one is.

There are a couple of points I would take up with you,

Sulphur, forms as H2S in some fermentations especially lagers so don't go blaming the beer to quick. To get sulpher taste in your beer from a bacteria you would also need a reduced metal in there as well.

Finally, contamination by an aceto bacter would lead to cloudy, vinegary beer, I appreciate that the other components may be there but you wouldn't get just astringensy. Same with a lacto infection, don't think because I have diacytl that I have a lacto infection unless you see a few other things as well, such as cloudy beer blowing bottles, wild fermentations.

These are points from experience, when I got into my issue with chlorophenols, I thought infection, Sure I had the Phenolic taste the problem was I had nothing else, not cloudy, no gushers, no ring. I spent hours trying to solve an issue that didn't exsist rather than concentrating on what I was seeing.

And why did I do that you ask? Because I had one of the criteria that defines an infection. You need to see more.

Today when I smell H2S I think hmmmmm, nice lager not Oh my god a bacterial infection. I would like to point out that I am yet to see an infection that doesn't cause ring to form around the neck of your bottle at gas liquid interface which has become one of my biggest identifiers.

Dogger

[kurtz]

oh now i get it..a beer can have off tastes and smells but its not infected unless you get a ring on the bottle or its a gusher ...interesting.

kurtz

[undercover1]

Kurtz, you seem to know your stuff...but so does Dogger.

If you two could work together and come up with some sound advice (maybe for use as a sticky) we'd all welcome it.

[Dr Love]

kurtz,

You seem to be a firm pooh pooher of the humble HDPE fermenter, jus wondering if you have personal experience with them and have had oxidation?
I use my HDPE fermenters frequently, and some of my brews have sat in them for 3 weeks without any ill effects on taste - and yes, I do know what oxidation tastes like.
Admittedly, I still like the idea of glass fermenters...

Cheers mate

[Jeff]

Phenolic..the big one..think band aids, think first aid stuff. pooh..bacteria and wild yeast cause this and it is the most comon infection from poor saniatation

Is this the same as the chlorophenol problem I believe this was the problem I had with a few brews and I blame the chlorine residue from the sanitiser. ie rather than poor sanitation, my problem was the sanitation. I've had fewer problems now I rinse in hot water before and after using the fermenter.

[kurtz]

ou seem to be a firm pooh pooher of the humble HDPE fermenter, jus wondering if you have personal experience with them and have had oxidation?

Ok you have to realise that oxygen has many effects.
Just after you have pitched your yeast (the aerobic stage) you are helped by lots of it (aerating the wort). Once the yeast gets going though oxygen is not a good friend, especially once the crazy first few days of fermenation have completed. The beer actually does not get oxidised as such, so the result is not oxidation (which is generaly a long term thing) but the possibility of aerobic bacteria and yeasts to go forth and multiply.
Infections are not black and white, low level infections are very common and may not make the beer totally undrinkable if the conditions for further growth have been halted.

HDPE containers..well how about this...22 litres of wort fermented for 22 days (nice combination) in an otherwise airlocked HDPE container will allow some 290cc of oxygen to diffuse through its walls.
This more than enough to encourage aerobic bacteria that may quite happily have entered your wort.

Kurtz

[db]

can i be a b@5t@rd & suggest that, because us homebrewer's can't sterilize our equipment/environment etc, that all of our brews are infected to some degree?
or would that just be me being silly?

[Dogger Dan]

You know some days its just not worth the added effort.

Kurtz drive on,

I am sure that crack I just heard was the sky falling

By the way, do you know what the barrier properties are for 5.5 mil HDPE? "just suck it in" is a pretty vague criteria.



Dogger

[kurtz]

Dogger
yeh sometimes you just have to lean back and say..why worry.!!!
...oh and the 5.5mm HDPE..thats pretty damn thick for a standard 25-30 litre bucket/fermentor but may be app. for a say a 150 litre plus jobby.
The figures I have are based on a basic 25 litre jobby.
Of course with a larger vessel (say 150 litre HDPE fermentor) then clearly the surface area to volume ratio reduces and thus so will the the diffusion of oxygen..apart from common sense you might like to look at Ficks Law for a far more detailed explanation.
But back to the beginning..I have only just joined this group and I did it (having read many of the publically available posts) from a desire to add some education and reality to it all.
All too often what a self called expert says on these sorts of forums is held as truth, when all too often the "expert" is actually a gasbag.
I do have some experience in the making of beer, and the judging of beer, and a decent amount of peer acknowledgement, and my knowledge is freely distributed...you only have to ask.

Kurtz

[MHD]

hehehe fun and games... Lets all go have a beer...

I'm pleased to hear all sides of the coin... in the end, like all I adjust the advice to suit my situation....

Hang around Kurtz... If not I will see you when I get round to dropping in on one of the ACT brewers meetings... (Would love to demistify the whole mashing thing....)

In the end its all about the beer!

[Dogger Dan]

Kurtz,

5.5 mil is tiny, look it up on a ruler.

I don't have any issues with what you say, thaey are all right, the issues is that I have with it that it is only half a story.

5.5 mil is the industry standard, Ropack, inform me that the barrier properties for oxygen on that thickenss is in excess of 3 months additionally, the pore size is small enough that bacteria will not travel through, did you think to mention that?

Then you say that bacteria will produce a sulphur smell in your beer. Can you please provide a mechanism for that to happen?

I know you know all there is to beer making, you have said that in your first six posts. You arrive on this site, tell everyone they know nothing because they can't identify a bacterial infection and that certainly all of us who haven't had one really do have them, then you proceed to tell 90 percent of the forum that there chosen method for brewing is crap and it is impossible for them to brew a good beer. Nice touch my friend, may want to write a book on how to win friends and influence people.

Lets step back a moment and look at acetar infections, where do the occur and what is required to make them happen, thats right at the interface between the liquid and the Oxygen. Many times what has happened is someone has lifted the lid off and allowed some O2 in to the vessel. As their fermentation is slow, as it is almost complete the acetar activates using the residual O2 from lifting the lid, it then generates CO2 (amongst other things) as it consumes the O2. Once the O2 is consumed the growth stops. Is it enough to pooch the beer, likely not, I admit there is an issue but all is not lost. Bottle it, and drink it. Is the beer infected? depends on your definition of infection doesn't it

So In conclusion, what your saying isn't wrong, it just isn't all the way there and rather than hammer me with book smarts and thumb your nose at me, take a look at the methodology. I hate to tell you a starter kit shouldn't consist of CO2 tanks and corny cylinders or stainless conical fermentors. They are going to consist of plastic primaries and syphon hoses so rather than say how crappy they are maybe you can get on board and tell folks how to use them

Don't bother about posting back on this as far as I am concerned I have said my piece in answer to your two thumbs and this one is dead to me. Send me an E-Mail, its available

Dogger

[pharmaboy]

"At the risk of repeating myself...if you have never had an infection how do you know what an infection is. "

This is an interesting question, a very large %, 1 in 30 or so bottles, of white wine are corked to some degree, yet almost no-one spots it unless it is really bad - but anyone who has been to a tasting where some examples have been shown has a much better chance of identifying it. I say much better, because without a good version of the same wine to taste, differences are difficult to detect- I can remember whether a wine was enjoyable before, a couple of attributes, but nothing beats an A/B comparison.

Having read your post, I was reminded of a belgian ale that i brewed that had a fault (ultimately repaired/hidden by the addition of sweetness), while I could have assumed infection (fitted your criteria) I reviewed method as compared to previous brews of the same recipe, and figured out it was likely a tannin problem with grains - longer boil than usual and at hotter temp.

My only doubts about infection stem from the obvious about requirements for bacteria, so this leads me to figure that the first hours are most at risk, and any infection would be runaway, so good yeast pitching is helpful. Of course the production of beer is an infection in itself.

To give a slightly different picture, A close relative has been brewing 40 years, brews in an open fermenter, secondaries to 30 year old ex vinegar plastic cubes, is a masters in chemistry (major paper on tannins), and maintains no infections - many faults, poor temp, boil wrong etc.

While all those tastes you mention could be attributed to infections, from personal experience I can also atrribute some of them to other differences in the beer making process.

[kurtz]

5.5 mil is tiny, look it up on a ruler.

Sorry, in my haste I read 5.5mm and metioned 5.5mm as well, domes from being metricated I guess. but is not about 0.15 mm pretty thin for the wall thickness of a fermentor.

5.5 mil is the industry standard, Ropack, inform me that the barrier properties for oxygen on that thickenss is in excess of 3 months additionally, the pore size is small enough that bacteria will not travel through, did you think to mention that?

Must be the industry standard then for clear film , I understand that Ropack is a Montreal based company that make packaging for the pharmaceutical industry, did you think to ask them if the barrier film contained oxygen scavenging polymers? (speaking of half the story)

Then you say that bacteria will produce a sulphur smell in your beer. Can you please provide a mechanism for that to happen?

As you know or should know sulphur compounds, particularly H2S and SO2 are produced as part of the fermentation process. In fact they are are, in very amounts, a help in the preservation of beer, and wine, SO2 has been added to wine since Roman times as a preservative. But you ask about sulphur producing bacteria, well you don't have to travel to some far away valley to find this, every brewer lierally has a mouthfull of them, they live on the tongue and tongue in cheek I must make the observation that the lack of a person to detect their haliotosis may be linked to a brewer not detecting his own infection !!

I know you know all there is to beer making, you have said that in your first six posts.

Don't think I do and don't think I said so.

Lets step back a moment and look at acetar infections, where do the occur and what is required to make them happen, thats right at the interface between the liquid and the Oxygen.

That is all the way round the plastic fermentor, it is HDPE, like most polymers it diffuses oxygen according to Ficks Law. It is permeable, I have given you the figures..did you read them or perhaps have a squiz at http://www.diffusion-polymers.com/.

So In conclusion, what your saying isn't wrong, it just isn't all the way there and rather than hammer me with book smarts and thumb your nose at me, take a look at the methodology.

Review, if you like my posts. I started by merely making the point

One post was in response to a white film on top of the beer the other a response to the remarkable number of brewers who have never had an infection.
At the risk of repeating myself...if you have never had an infection how do you know what an infection is.
Infections most commonly are fairly low level but certainly detectable to the palate.
As most brewers clean their fermentor fairly well it is unlikely that an infection will arise from a dirty fermentor directly.

I was pretty nice and pointed out that an infection could be low level,that there were many causes of infection and that infection could arise is a fully airsealed CO2 blanked fermentor.
I am all about educating people about beer, I have run classes on all grain brewing at a local college, I get involved in public demonstrations, for two years I have helped all day at the most ppopular stand of all at the Australian Science Fair..the brewing stand, I am a beer judge as well.
If you make a beer that is slightly infected and do not recognise it how are you going to make better beer??
Frankly if you do not mind or have a taste for infected beer then by all means say it not infected and go ahead and drink it, just do not offer it me.
I am hopping in the car in two hours for a well desrved trip to the South Coast..enjoy your weekend and may all of you be happy in the knowledge that your beer is not, by some definitions, infected.

Kurtz

[Dogger Dan]

Nice Kurtz,

I have been had, good for you


Kinda thought something just wasn't quit right, you can let go of my ears now please.

Dogger

[tyrone]

I know that all my beers are infected They all contain the dredded wife altering bacteria After I consume a moderate amount of the afore said bacteria the wife in question will only give me one thing The dredded hot tounge and cold shoulder

[mark68]

I've just tasted my latest brew and am not happy with the result. it has that distinctive homebrew flavour which ,as i have found before,doesn't go away with aging.I used 1.5 kilos of BE 2 to brew this batch and have never had this trouble before when using the same.Could this be an infection causing this?

[kurtz]

Without knowing the exact taste ("homebrew" covers a wide range of tastes !) I can only guess that it is an infection.
Is is reminiscent of bad-aids, is it clovey (and not a wheat beer), is is highly estered, is it it cloudier than you would wish, does it fizz alot....??

K

[WSC]

Sorry to raise one from the dead but I have a question on this topic.

I have a wheat beer that I made from morgans wheat (golden sheaf) and a 1kg tin of morgans liquid wheat extract.

There is still a foamy sludge on top of it after 10 days in the fermenter using safwheat yeast.

I scraped some of the sludge off the top, it didn't smell bad but was just very different to what I have seen in my last 11 brews.

I took a sample and let it sit over night, on top of the sample was a white foam, not a oily film or anything like that.

The hydrometer is at 1014 and dropping slowly I expect it to get to 1012.

If the hydrometer is the same 2 days in a row and I bottle infected beer is there still a chance the bottles will explode?

I refuse to throw it out!!!!

[Aussie Claret]

Hi
I suspect that this is only Krausen and not an infection. Wheat beers generally have considerable amounts of Krausen more than your usual ales or lagers.
Don't worry.
AC