mystery cheese pt.2

[mr.jay]

It's baaack!
That's right folks, this time in a heffeweisen. Those who don't know what I am talking about, I'll bring up to speed, so you can finish the sequel without reading the first part. I brewed an alt about 2 months ago, in my dish fermentor (I don't use it all the time). Transfered it into a unitank, and it tasted like cheese. Lagered it, filtered it, rolled the dice, and it wound up tasting alright. Climbed into the tank, scrubbed the dickens out of it, inspected it, ran a second CIP cycle, and proceded to brew a heffe. Transfered it a few days ago, came in this morning, and gave it a try. Nothing gets the stomach going like a swig of cheesy beer at 7:00 in the morning. And this time, it's worse.
Some other things to consider. The dish fermentor is fitted with an airlock that doesn't work, so it's truly an open fermetation. I probably could have pulled it a day or 2 earlier, but there was minimal activity, which still indicates (to me) positive pressure in the vessel. Besides, even if it finished fermenting, I find it hard to believe that the very same culprit could get in there twice in a row, for 2 different reasons. Sure it's possible, but I've had close calls on other beers in different vessels, and never experienced such a thing. What is this cheesy taste? I don't believe it's butric acid, I've smelled and tasted that before. It's not in the nose at all, in fact, maybe taste and smell are bad descriptions. It's more of a sensation, as if somebody poured some juice from a feta cheese container into the beer (now there is an idea for a beer). My sanitation/cleaning practices when using the dish are just as thorough, if not more than when I clean other tanks. The hoses and pump are also thoroughly cleaned. What should I be looking for, and how do I get rid of it, so we don't have a part 3 to this epic saga starring a disgruntled brewer.

[liammckenna]

Cheesy, vomit like, I've seen it before, perhaps not exactly what's going on at your gaffe but I agree that there are few things like a cheezy beer, especially when it's your own. Isovaleric acid is the marker compound. Smells like the Jacks in any Temple Bar pub on a Saturday nighgt.

Wild yeast infection, Brettanomyces was the culprit. It made for an interesting but totally unexpected Dublin dry stout.

Apparently, it rarely survives above 5% alcohol, making it difficult to culture from a higher gravity finished beer. Difficult, but not impossible.

In our case, I had no idea where it came from but we reacted with all guns blazing. Replaced all beer hose (upon inspection some interiors were cracked in the discard pile), broke down heat exchanger, replaced gasket sets (plates were not too bad, minimal deposits), cleaned and inspected all pump faces, cultured swabs of all hard piping before and after each junction, re-evaluated cleaning procedures and chemical application levels...and probably other things I can't recall. We were in the midst of yeast re-propagation so, we had a known pure culture to replace our pitching stock. Cultures of discarded pitching yeast, didn't find WY infection, even after numerous different media and techniques. Suspect it became resident in a too old piece of hose. Could be wrong. Still mystifies me.

Good luck with it.

Pax.

Liam

[mr.jay]

Quote: Apparently, it rarely survives above 5% alcohol, making it difficult to culture from a higher gravity finished beer. Difficult, but not impossible.


It's interesting to note that both of these beers were well above 5%. The alt, being a Sticke @ 6.5%, and the Heffe being more suited for the cooler days (similar to "Schnider Weiss") weighing in at 6.2% abv.. If it is in fact this acid you speak of, it is most likely isolated to the dish, and everything making contact with it since. I have already transfered and cleaned the tank holding the first culprit, and replaced it with a golden ale (@4.5% abv) and it seems fine. I am concerned about one of my hoses. B.T.W., how do you inspect the inside of your hoses without an orthoscopic camera? That is something I would like to do. I'm not looking forward to taking everything apart, but it may be the only way. Thanks for your input Liam!
Jay

[beertje46]

Smells like the Jacks in any Temple Bar pub on a Saturday nighgt.

Good luck with it.

Pax.

Liam

I'm not sure what the above refers too.

[liammckenna]

Reference to Temple Bar: washrooms are often reeking of vomit of a Saturday night.

Having lived in Dublin for four years, noted that the locals tend to avoid this area on busy evenings. We sold a lot of beer there. It got so bad at one point that local council was talking about a ban on English stag parties of more than 6 participants.

Possible Brett. contamination:

An othoscopic camera would work for hose inspection but few of us have access to such a luxury.

Unfortunately, the only other way is to remove sections, cut longitudinally, and turn it inside out to visually inspect. Perhaps sacrifice your questionable hose for inspection. If it's fine, you could create two shorter ones if you've got extra fittings about.

In terms of culturing Brett from a higher gravity beer, it is a spore former. My recollection tells me that that was key to culturing... to encourage spores to grow as no viable regular cells were present.

Pax.

Liam

[jason.koehler]

Quote: Apparently, it rarely survives above 5% alcohol, making it difficult to culture from a higher gravity finished beer. Difficult, but not impossible.


It's interesting to note that both of these beers were well above 5%.

It's possible you had the infection up and running before it hit 5% in the fermenter, and even so...5% isn't a magic number that makes the Brett infection stop munching immediately, it would take some time to wind down.

If you got the infection through a hose or the heat exchanger, it could have been eating away happily on whatever was left over in it when it got whisked away into a paradise of fresh sugars, already primed up and ready to start eating. In the meantime, your brewers yeast was just starting to wake up and hadn't had it's double shot of espresso yet.

[Moonlight]

Check rubber seals in valves. I know a brewery that sometimes uses Brett, and any non-stainless part is removed from the tank and swapped for a non-Brett set when "normal" beers are made...manway gasket, sightglass, sample cock, etc

[crassbrauer]

Brettanomyces are slow fermenters but can handle up to 15 % abv. They're a problem for winzers. You mentioned you had basically an open fermenter. They like the conditions in the latter stages of fermentation, when the foam has fallen and a little air is present above your beer.

Pediococcus can, in some cases, cause a cheesy aroma. You might want to check your quality control program for holes.

What about your pitching yeast? They could be a source for either or both of these critters.

[crassbrauer]

By the way, I accidently used the German word. I meant "vintners" above.

[Todd]

Mr. Jay.

You may want to consider using a testing method referred to as wort stability sampling. You need to have a sample port on your wort main directly after your product exits your heat exchanger, a sample port added on the far side of your hose before the inlet valve of your tank, and a sample port on your tank. You will need some centrifugal sample tubes that are used for aerobic and anaerobic microbial growth. On your centrifugal tubes you need to mark; heat exchanger, hose, and tank along with the date/ the batch# and the FV #.
You need to take aseptic samples from each one of these locations after you do your sanitation and while the wort is in route to the fermenter. Your tank sample must be taken before you pitch your yeast into the fermenter.
Let the samples sit at room tempurature (incubation temps preferrably). If any one of these samples start bubbling within 24 hours you know you have something going on. This allows you to isolate the problem area in your production. The best way to grade your sanitation practices is to give yourself a grade A for a sample lasting 96 hours or more without fermentation, a grade B for a sample lasting 72 hours, a grade C for a sample lasting 48 hours and a grade F for a sample lasting only 24 hours. I have seen samples lasting as long as two weeks.
From here you might be able to detect this bacterial.
This is really your first step to simple wort QC in a small brewery. I would highly recommend this method every time you brew. There are many other fairly simple methods for the small brewer.

- Todd

[kugeman]

Rather than centrifugal sample tubes you can also use sterile bags. I get mine from Whirl-Pak. They're super easy to use and not very expensive. It's a simple QC procedure, but I worry alot less about the cleanliness of my heat exchanger because I pull samples every brew. Just a thought...

[Todd]

Kugeman,

Are whirlpack designed for aerobic and anaerobic microbial gowth?



-Todd

[kugeman]

The ones I use are for aerobic growth only. I checked their website www.enasco.com/whirlpak/ and I don't see any anaerobic growth test equipment, but I could be missing it.