Identification of the infection (microscopic photos).

[Juranto]

Hello everyone,

unfortunately I have been struggling with an infection in beer for a long time. Beer tastes normal when bottled until around three weeks, then starts a strange aftertaste and gushing. I changed the equipment, used caustic soda, the problem returns. In order not to prolong the story, annoyed by this situation, I bought a microscope.


Test results of my last two beers. Fortunately, I have yeast slurries of these beers, and perhaps it will be possible to determine if contamination occurred during bottling or fermentation.

- light Ale, yeast K-97
* yeast slurries:






* bottle grounds:





* sediment visible on the bottle:



In the second post I will add photos of the second beer.

 

[Juranto]

- Belgian Dubbel, Belgian Ale M41 yeast
* yeast slurries:





* bottle grounds:








As I am just starting my adventure with microbes, I would be grateful if someone could help identify the cause. The yeast varies in size, but I cannot say if wild yeast is also included.
With Belgian Dubbel in the bottle clearly the majority of dots (bacteria), this beer after more than a month has no gushing, but a terribly strange taste.
Light Ale cannot be opened normally, there is gushing. Before bottling this beer was 1.010, now 1.002 gravity.

Is there anything specific to the infection of these two beers or are they two separate cases?
Thanks for any help.

 

[Vale71]

There doesn't appear to be anything but yeast in those pictures. Did you at any time in the past brew a saison using a saison-specific yeast?

 

[homebeerbrewer]

I'm not a microbiologist, so I can't identify what's in your pics, but maybe I can help with your process. You said you used caustic to clean. What do you use to sanitize? Cleaning alone won't get rid of an infection.

 

[Birrofilo]

I suppose you could try several colouring substances to see if you have some bacteria which reacts to a certain colouring substance and becomes evident. The normal bacterium is much smaller than a yeast cell.

Although the microscope examination is certainly interesting in itself, I don't think it's easy to find the culprit and, even if you find it and identify it, the steps to eliminate it are probably the same whatever his ID.

I don't want to discourage your scientifical approach, but if I were you I would do something different:

Brew at a friend's (or at a second home etc.) but bring all your equipment. This should tell you if the infection comes from the equipment, or the environment.

If the infection comes from the equipment, consider cleaning operations that you normally don't do, such as dismounting taps, cleaning threads of taps, sterilizing taps, substition of gaskets, use of different detergents and sanitizers; The kettle tap is an obvios source of problems, as well as racking canes, which can be hard to clean and sanitize well (try a new racking cane without throwing away the first).

If the infection comes from the environment, I suggest buying an ozone generator and use it to sanitize your working room. That can kill many bacteria and viruses which can simply cling to your walls and furnitures. It also can damage stainless steel, so take your steel away. Ozone is bad for you, you must adopt precautions when using it (simply don't stay in the room, and aerate the room thoroughly after use).

Clean everything maniacally in your brewing room: the traces of black mold near your sink are a possible source of problem. It goes without saying, dogs and cats should not be allowed in the brewing room.

EDIT: rereading now that you "changed the equipment". I would concentrate on the environment, but would do the test of brewing elsewhere in any case.

 

[Juranto]

Thanks to everyone for your interest and answers.

Perhaps I misspelled myself, not exactly identifying a specific infection, but when it occurs. First, whether it could be a bacterial infection or a wild yeast infection. There are little dots in the Belgian beer bottle, isn't that just bacteria? In the yeast slurries (i.e. before bottling), it is not visible.

In the light ale beer, on the other hand, a strange oval form of yeast is visible, could it not be wild yeast?

Is nothing identifiable?

My idea was that the next time I brewed my beer, take samples at each stage and compare them so that I could tell where the contamination occurs, but then does that make sense?

There doesn't appear to be anything but yeast in those pictures. Did you at any time in the past brew a saison using a saison-specific yeast?

No, I haven't brewed that kind of beer.

I'm not a microbiologist, so I can't identify what's in your pics, but maybe I can help with your process. You said you used caustic to clean. What do you use to sanitize? Cleaning alone won't get rid of an infection.

First, it washes with a sponge washing-up liquid, then soaked with a caustic soda solution, rinsed thoroughly with water, and finally starsan.

I suppose you could try several colouring substances to see if you have some bacteria which reacts to a certain colouring substance and becomes evident. The normal bacterium is much smaller than a yeast cell.

Although the microscope examination is certainly interesting in itself, I don't think it's easy to find the culprit and, even if you find it and identify it, the steps to eliminate it are probably the same whatever his ID.

I don't want to discourage your scientifical approach, but if I were you I would do something different:

Brew at a friend's (or at a second home etc.) but bring all your equipment. This should tell you if the infection comes from the equipment, or the environment.

If the infection comes from the equipment, consider cleaning operations that you normally don't do, such as dismounting taps, cleaning threads of taps, sterilizing taps, substition of gaskets, use of different detergents and sanitizers; The kettle tap is an obvios source of problems, as well as racking canes, which can be hard to clean and sanitize well (try a new racking cane without throwing away the first).

If the infection comes from the environment, I suggest buying an ozone generator and use it to sanitize your working room. That can kill many bacteria and viruses which can simply cling to your walls and furnitures. It also can damage stainless steel, so take your steel away. Ozone is bad for you, you must adopt precautions when using it (simply don't stay in the room, and aerate the room thoroughly after use).

Clean everything maniacally in your brewing room: the traces of black mold near your sink are a possible source of problem. It goes without saying, dogs and cats should not be allowed in the brewing room.

EDIT: rereading now that you "changed the equipment". I would concentrate on the environment, but would do the test of brewing elsewhere in any case.

Thanks, I'll take a look at the tap and other things for sure.

 

[Qhrumphf]

I don't know details but there's supposed to be specific plating media that'll only grow wild yeasts (or so I'm told).

I don't see anything but yeast either. And you're not gonna have an easy time figuring out what kind of yeast from visual alone. If you've got a brewery nearby that has a proper lab, they might be able to run a PCR test and check for diastaticus (which if a brewery has only one thing they're able to check for that's probably it).

Because what you're experiencing sounds like diastaticus (a specific subset of S. cerevisiae with a particular gene that allows it to break down higher saccharides into fermentable sugars. Saison yeasts are the primary examples but they're not the only ones).

 

[Qhrumphf]

Some of the more zoomed in ones might show some stuff, though they still look large to be bacteria in my dangerously uneducated opinion. Staining might help. But IIRC yeast, pedio, and lacto are all gram-positive, and the common gram-negative spoilers (at least the ones I can find with a quick google) tend to be rod shaped, which I'm not really seeing.

Wild yeasts are often smaller than domesticated brewing yeasts. So my bet is those smaller cells are your wild contaminant problem.

 

[homebeerbrewer]

First, it washes with a sponge washing-up liquid, then soaked with a caustic soda solution, rinsed thoroughly with water, and finally starsan.

Ok, what you're doing seems fine. Does that include the bottles? Are you using new bottles, or reused?

On a different direction, what do you ferment in? Plastic? Glass? Stainless?

 

[Vale71]

Those small dots are most likely particulate as they appear to be free of any internal structure but to be sure you'd need a higher magnification and to switch to dark field if your equipment allows for that. The elongated shapes appear to be yeast in the final stages of budding. Yeast can really take on funny shapes when it's "doing the nasty".

To be more effective in diagnosing a probable infection you'd need to do a culture, either liquid or agar plate, with one or possibly several selective culture media but that's really quite advanced for a homebrewer.

 

[Miraculix]

Ohhh this is an interesting thread. Please keep us updated! Also with pictures

 

[Juranto]

Ok, what you're doing seems fine. Does that include the bottles? Are you using new bottles, or reused?

On a different direction, what do you ferment in? Plastic? Glass? Stainless?

It ferments in plastic. I normally use half of the bottles new and half the used ones, washed and roasted in the oven, they all have the same infection.

 

[homebeerbrewer]

The roasting glass in the oven part scares me, but then again, glass and me don't mix well.

Your fermenter is most likely the source of infection. It could have tiny scratches where bacteria can hide. It may be time for a new fermenter.