Source of common infections

[doctorRobert]

I'm kind of newb, and I was just thinking what the sources are of most infections and when they occur.

From what I read, most infections would occur prior to fermentation, is that correct? And once a beer ferments odds are you're in the clear. Now, this makes me think that a source of some infections could be the pitched yeast. Is it possible to get infected yeast from like wyeast or white labs? That seems to make more sense than the random spoon i had lying around that wasn't sanitized.

I want to try to open ferment a hefe...is that just a crazy idea? Or am I stupid for even wants to try that.

 

[Mischief_Brewing]

Infections can happen post ferment as well (do some searches on gushers).

No don't quote me on this, but I'm guessing that Wyeast and While Labs have way, WAY better sanitary measures that they adhere to than the average homebrewer.

Bacteria can hide in and on just about anything. I've gotten infections from an improperly cleaned siphon and tubing, vanilla beans, and from letting a CO2 seal dry out (at least, that's my best guess for those brews after re-reviewing my notes for the 1000th time).

The best thing that I ever heard is that "nothing deadly" can grow in beer. You might have horrible tasting swill, but it won't kill you. With that said, definitely go for the open fermentation and even try some wild yeast experiments. Pretty hard to duplicate a success, but if you get a success, you'll be pretty stoked...

 

[TipsyDragon]

i think its highly unlikely you would get an infected yeast packet from a reputable manufacturer. this is their business and take it seriously. if infected batches got out it would kill their business.

in fact its way more likely that the "random spoon" is the source of your infection. an infection can come from anything that touches the beer post boil that hasn't been properly sanitized. scratched buckets are well known for causing infections across several batches.

if your going to experiment with open brewing you should look into lambics.

 

[moonbrew]

You're right in that "most" infections occur before fermentation, because unfermented wort is perfect food for micro organisms. Fermented wort, beer, is less perfect but does contain unfermentable sugars that wild yeast, or bacteria can feast on. In other words, sanitation is paramount before fermentation, and still important post fermentation.

As far as infected yeast from Wyeast or White Labs... that is highly unlikely. These two companies could not do business if infection were a likely possibility. In fact, on the back of a Wyeast smack pack it says "guaranteed pure". However, if you don't sanitize the bag before you pitch it, the bugs on the outside of the bag could hitch a ride right on into your fermentor. Again, something Wyeast warns about right on the back of the bag. These smack packs and vials were packaged in laboratory like environments, they're clean. That random, unsanitized spoon you have lying around... I would bet has bacteria on it... EVERYTHING has bacteria on it and maybe wild yeast, that's the way nature works.

Open fermentation isn't a crazy idea, but its kind of tough to do consistently. Your just as likely to get something undrinkable as you are wonderful in some cases. There are yeasts that can get you close to the hefe your looking for without the "open" part if you want to play it safe.

My 2 cents

 

[ReverseApacheMaster]

The source of infection will almost always be something you failed to properly clean in your home. The only things in your home guaranteed to be completely sanitary will be anything boiling, the interior of yeast packaging, and anything you fully boiled and packaged in airtight, boiled compartments prior to cooling. (ok, and chemical/liquid potent enough to kill any microbes that comes in contact with it)

That's it.

Everything else has bacteria, wild yeast, mold spores, etc. on it. Thorough cleaning followed by a no-rinse sanitizer is your best bet to try to get as close to 0% contaminants as possible, but you can still have bacteria in a small scratch or impurity in the plastic that didn't get hit with sanitizer.

 

[mojotele]

Another common source of infection is you. You have all sorts of microorganisms all over and inside you RIGHT NOW!

 

[SwampassJ]

 

[doctorRobert]

Well that's kind of my point... EVERYTHING has bacteria...and sanitizing it does not kill ALL bacteria. Since we're not brewing in a sterile environment, i'm just surprised infections aren't more common.

 

[SumnerH]

Well that's kind of my point... EVERYTHING has bacteria...and sanitizing it does not kill ALL bacteria. Since we're not brewing in a sterile environment, i'm just surprised infections aren't more common.

Infections are probably pretty common*, but infections with any noticeable symptoms aren't.

You pitch a ton of Saccharomyces. It'll overwhelm bacteria initially, and once fermentation is done then most of the edible sugars are gone and there's alcohol and hops to help inhibit bacterial growth.

Ask people who intentionally brew sours: they pitch a _ton_ of bacteria and it can still take months to be noticed and a year or more to develop a decent sour profile.

If you've gone out of your way to sanitize things (rather than pitching hundreds of billions of bacteria on purpose), it's not too surprising that it's fairly uncommon to get noticeable off flavors.


*White Labs did a study showing 11% of beers tested had some bacterial presence, though not necessarily enough to affect taste or appearance. http://www.whitelabs.com/qcday-2010.html

 

[ReverseApacheMaster]

Well that's kind of my point... EVERYTHING has bacteria...and sanitizing it does not kill ALL bacteria. Since we're not brewing in a sterile environment, i'm just surprised infections aren't more common.

Actually, that seems to be the opposite of your original position, but ok.

The reason why infections are not very common is because:

1. Sanitation kills a lot -- the more dilligent you are, the better chances your beer has

2. Alcohol kills many bacteria

3. You should pitch enough yeast so that no other yeast have an opportunity to gain a foothold in the wort and multiply

 

[doctorRobert]

Actually, that seems to be the opposite of your original position, but ok.

The reason why infections are not very common is because:

1. Sanitation kills a lot -- the more dilligent you are, the better chances your beer has

2. Alcohol kills many bacteria

3. You should pitch enough yeast so that no other yeast have an opportunity to gain a foothold in the wort and multiply

I didn't have an original position, I had a question about contaminates in the yeast. I was thinking it of like a bag of grass seed. Every bag of grass seed has weeds in it. The amount depends on brand. I had a thought maybe yeast was the same way, I'd imagine it'd be pretty impossible to create condition to harvest/grow yeast, but to make it impossible for other bacteria to grow.

 

[Wellshooter]

The source of infection will almost always be something you failed to properly clean in your home.

I read the other day that the most bacteria free ( i.e. cleanest) place in your house is the toilet seat. I don't think that applies all the time to single men.

 

[Castawayales]

I had an infection caused on bottling day when I let my dog in from outside in a rainstorm and he of course shook as he walked by the kitchen table.

Beer tasted great at bottling. Went downhill after 3 weeks. I bottle in a different area now.

You can get an infection at any time because beer still has a lot of sugar when finished and a relatively low alcohol content. Keep things clean and sanitized and you should brew great beer all the time.

 

[Justibone]

I read the other day that the most bacteria free ( i.e. cleanest) place in your house is the toilet seat. I don't think that applies all the time to single men.

Urine is sterile when it leaves your body (unless you have a UTI). There is a tribe in Africa that actually use their cows' Number Ones to wash their hands.

True story.

 

[Justibone]

I had an infection caused on bottling day when I let my dog in from outside in a rainstorm and he of course shook as he walked by the kitchen table.

Beer tasted great at bottling. Went downhill after 3 weeks. I bottle in a different area now.

You can get an infection at any time because beer still has a lot of sugar when finished and a relatively low alcohol content. Keep things clean and sanitized and you should brew great beer all the time.

Dry wines -- especially using champagne yeast -- are relatively impervious to infection when they've fermented up past 15%. Beers are only 5-10% (max) and are very rarely "dry"... so yeah, +1 on fermented beer still being vulnerable.

 

[BlueSunshine]

Ever since my ceiling came down over my kitchen where I brew, I've been paranoid about infections. However, I find that keeping a spray bottle filled with Star San solutions around and spraying everything is a great way to sanitize. I spray EVERYTHING with it.

Just try not to get it on counter tops, it can ruin the finish.

 

[doctorRobert]

i think its highly unlikely you would get an infected yeast packet from a reputable manufacturer. this is their business and take it seriously. if infected batches got out it would kill their business.

in fact its way more likely that the "random spoon" is the source of your infection. an infection can come from anything that touches the beer post boil that hasn't been properly sanitized. scratched buckets are well known for causing infections across several batches.

if your going to experiment with open brewing you should look into lambics.

I just want to point out what I found:

http://www.danstaryeast.com/munich.html
Living yeast cells 5 x 109 per gram of dry yeast
Wild yeast < 1 per 106 yeast cells (Lysine method)*
Bacteria < 1 per 106 yeast cells*

So yes, wild yeast and bacteria do come in your yeast. I guess I'm not so crazy after all.

 

[mojotele]

I just want to point out what I found:

http://www.danstaryeast.com/munich.html
Living yeast cells 5 x 109 per gram of dry yeast
Wild yeast < 1 per 106 yeast cells (Lysine method)*
Bacteria < 1 per 106 yeast cells*

So yes, wild yeast and bacteria do come in your yeast. I guess I'm not so crazy after all.

Interesting. Seems what they're saying is that in a 11 gram yeast packet there are 55 billion yeast cells (the figure you copied and pasted is actually 5*10^9 per the PDF) and only 55,000 cells of wild yeast and 55,000 cells of bacteria (each having 1 cell per 10^6 yeast cells). So the packet is 99.9999999999% (repeating for a long time) brewers yeast. So, you are correct, there are wild yeast and bacteria in a packet of yeast. However, I'd say the following:

Now, this makes me think that a source of some infections could be the pitched yeast.

is so remote that it can be declared impossible assuming quality control stays consistent.

 

[Shooter]

I just want to point out what I found:

http://www.danstaryeast.com/munich.html
Living yeast cells 5 x 109 per gram of dry yeast
Wild yeast < 1 per 106 yeast cells (Lysine method)*
Bacteria < 1 per 106 yeast cells*

So yes, wild yeast and bacteria do come in your yeast. I guess I'm not so crazy after all.

Yep, there's bacteria almost everywhere, but as to yeast being a source of "some" infections per your original post, VERY unlikely, but anything is possible. As far as yeast being a "common" source of infection, per the thread title, no way. Let's be specific here also, we're talking infected in terms of having a detrimental effect on the beer. Just because there are bacteria cells present you could technically say it was infected, but that's twisting things to suit an argument.

 

[Justibone]

... in a 11 gram yeast packet there are 55 billion yeast cells (the figure you copied and pasted is actually 5*10^9 per the PDF) and only 55,000 cells of wild yeast and 55,000 cells of bacteria (each having 1 cell per 10^6 yeast cells)...

So the bacteria and wild yeast are outnumbered 100,000:1?

So, the bacteria and wild yeast are like the home team's starting quarterback in an NFL stadium (Payton Manning, perhaps), meanwhile the yeast you paid for are represented by EVERYONE ELSE IN THE STADIUM as well as a few blocks radius around the stadium!

Wow... somehow I don't think that's too much of a problem!

http://answers.kgb.com/how-many-people-fit-in-lucas-oil-stadium/1559603

 

[lamarguy]

Infections are probably pretty common*, but infections with any noticeable symptoms aren't.

*White Labs did a study showing 11% of beers tested had some bacterial presence, though not necessarily enough to affect taste or appearance. http://www.whitelabs.com/qcday-2010.html

George Fix stated something like "mild infections are often the difference between a good and a potentially great homebrew" in several of his books (late 90's). I imagine the 11% figure is much lower than the actual "mild" infection incidence in the homebrew community.

I mean, 2 out of 3 brewpubs in OKC I visited last year had a "moderate" infection in one of their beers...

 

[LumberjackJohn]

I have to agree with Jdecarol. Lohan is a large source of some common infections, and many uncommon ones!

 

[remilard]

George Fix stated something like "mild infections are often the difference between a good and a potentially great homebrew" in several of his books (late 90's). I imagine the 11% figure is much lower than the actual "mild" infection incidence in the homebrew community.

I mean, 2 out of 3 brewpubs in OKC I visited last year had a "moderate" infection in one of their beers...

He was quoting an "old brewing adage" that I have never seen anywhere else but is a good thing for people to believe even though it runs counter to dogma here.

I think it is closer to "major infections are rare in brewing but minor infections are killers".

Anyway, that 11% figure is from commercial beers. The "Great Pale Ale Project" or something like that from quite a while ago on HBD had a number of experienced homebrewers brew the same recipe and subject them to lab analysis and most of them had bacterial contamination that would have been unacceptable to a commercial brewery.

Anywho, judging competitions has clarified for me how common infections (not even minor ones) are in homebrewed beer.

 

[doctorRobert]

So the bacteria and wild yeast are outnumbered 100,000:1?

So, the bacteria and wild yeast are like the home team's starting quarterback in an NFL stadium (Payton Manning, perhaps), meanwhile the yeast you paid for are represented by EVERYONE ELSE IN THE STADIUM as well as a few blocks radius around the stadium!

Wow... somehow I don't think that's too much of a problem!

http://answers.kgb.com/how-many-people-fit-in-lucas-oil-stadium/1559603

While that's true, yeast aren't attacking killing infectious bacteria. And infectious bacteria can live off of non-fermentable sugars. So over time, lets say in the bottle, these outnumbered bacteria, can reproduce themselves into significant amounts eating non-fermentable sugars?

I never meant to suggest that infections from the yeast packet will spoil the beer. I was never suggesting that most infectious are caused by the yeast. If I did so, that's my mistake, I was just thinking that it could be possible for this to happen. Everyone always claims that almost all homebrews have some level of infection or foreign bacteria, and so maybe it is more common then you think, and given enough time, it could ruin a batch of beer.

 

[Justibone]

While that's true, yeast aren't attacking killing infectious bacteria. And infectious bacteria can live off of non-fermentable sugars. So over time, lets say in the bottle, these outnumbered bacteria, can reproduce themselves into significant amounts eating non-fermentable sugars?

If they survive the ethanol poisoning...

 

[Shooter]

If they survive the ethanol poisoning...

Exactly!

After fermentation is complete it's not just competition with the yeast they have to worry about.

Is a "yeast infection" possible? Like I said, anything is possible, but is it likely or common? Probably not.

 

[lamarguy]

Anyway, that 11% figure is from commercial beers. The "Great Pale Ale Project" or something like that from quite a while ago on HBD had a number of experienced homebrewers brew the same recipe and subject them to lab analysis and most of them had bacterial contamination that would have been unacceptable to a commercial brewery.

Thanks, found it - The HBD Palexperiment Results.

9 out of 34 (27%) were bacteria free, according to a LMDA test. I don't believe LMDA tests for wild yeast, though, so the percent clean would likely be even lower.

But, like you said, the "no infection here" dogma is pretty evident.

judging competitions has clarified for me how common infections (not even minor ones) are in homebrewed beer.

Very true. I've had a few 10 entry flights that had 5+ infected beers. But, I've been through 15 entry flights that had 0 infected beers, so it's all relative.

My point was - a mild infection is enough to drop a mid 40's scoring beer into the 30s, even if the judge can't precisely identify the off-flavor. He/she just knows it tastes "off".

 

[Justibone]

Is a "yeast infection" possible? Like I said, anything is possible, but is it likely or common? Probably not.

Yes, a "yeast infection" is possible, but it is more likely to be a "tamed" yeast you didn't want than a wild yeast. Yeast, like dogs, have been bred over centuries to do what we want them to do, and wild yeast (like wolves) don't thrive in the environments men create for our own purposes (making beer).

It's not that it doesn't happen, but it is less likely.