Clove flavor source US-05?

[Dland]

I had a couple of batches of ale recently come out with a definite clove taste. I used US-05 at 68F in both cases, and it was the second batch of wort for each pitch with a good sanitation after the first clovey batch was detected. The first batch of both pitches came out as expected, the second ones had a clove flavor. I often brew back to back brews on yeast cake of previous pitches w/o unsealing fermentor. I've gone as many as eleven successive batches with good success, though the longer runs have usually been cold fermented lagers.

While not as overwhelming as the time I got clove from BE-256 a few years back, it is enough to be a flaw in flavor to my taste.

The obvious conclusion is I somehow picked up a infection with a yeast that makes clove taste. The other possibility is that the packets of US-05 were not a pure as they could have been, and contained traces of some kind of farm or Belgium yeast contamination, and the contaminating yeast got a good foothold in fermentor after first batchs. Yeast packets were from the same run produced in 2022.

Anyone else who does successive batches on same yeast cake get this result with US-05 lately?

In any case, I did a thorough breakdown sanitation of gear and am brewing a second batch on a pitch of S-04 right now, hopefully problem solved.

 

[Miraculix]

That's a typical contamination with a wild yeast I'm afraid hopefully you managed to get rid of it! Otherwise, bleach bombing helps usually in these cases.

 

[MaxStout]

Interesting, since BE256 is non-diastatic. Yet, there could be remnants of that yeast which could introduce a clove off-flavor.

Disinfect your gear, replace plastic components, etc.

 

[dmtaylor]

US-05 doesn't make clove. Contamination by other yeast does. You've got contamination. I would be extremely skeptical of blaming it from anything inside of the yeast packet. It came from someplace else.

 

[Dland]

I'm aware US-05 is a clean yeast, my first guess is contamination also, just putting it out there in case I was not the only one.

As we know, sometimes products are defective from manufacturer, so I would not rule it out completely. The fact the brews from the first pitches came out clean in two successive runs and second successive batches were clovey straight out of fermentor is what makes me wonder. Also, if on the off chance it was slightly contaminated from fermentis, this would not be detected by most brewers not doing "cone to cone" brewing.

That said, a trace infection in fermentor could also be amplified over time, and I acknowledge that. However, this is a stainless conical, and full sanitation cycle was done between pitches.

I mis remembered the yeast in first clove indecent, it was BE-134, not 256, but could not be related to latest case, as that was in 2019 and 115 batches ago.

 

[Bazza McKenzie]

A quick search turned up numerous anecdotes similar to the OP.
It’s definitely not unknown for US-05 to kick out clove-like phenols.
People who have encountered this generally do a bit of head scratching and experimenting to try and narrow down the problem. Most seem to conclude it is indeed US-05 which is the common factor ie using a different yeast to eliminate factors such as water and equipment contamination.

I don’t use US-05 much, but I’ve experienced unexpected clove flavour from yeast a couple of times when using WLP002.
I went straight to the ‘wild yeast contamination’ explanation, but subsequent events cast doubt on the idea. Eventually I concluded it was more likely stress related mutations rather than wild yeast.

 

[ba-brewer]

I believe a yeast has to have the gene to generate phenolic flavors, so if it is not listed as POF+ stress would not cause it.

The couple time I had a clean yeast (wlp029)go phenolic it took a few pitches to be pronounced. If it was something that was in your initial pitch I would think there might be some signs of it for the second pitch to be full on phenolic.

If the tainted beers are phenolic and fairly well behaved (not overly cloudy or have other off flavors) it is most likely a cross contamination of a commercial yeast and not something wild. If you don't brew with POF+ then coming in with the initial pitch seem like a possibility.

I think my contamination came through the jar I use for storing yeast. I stopped using POF+ for a while and started heat treated my yeast storage jars and have seen the issue in a while.

 

[Miraculix]

A quick search turned up numerous anecdotes similar to the OP.
It’s definitely not unknown for US-05 to kick out clove-like phenols.
People who have encountered this generally do a bit of head scratching and experimenting to try and narrow down the problem. Most seem to conclude it is indeed US-05 which is the common factor ie using a different yeast to eliminate factors such as water and equipment contamination.

I don’t use US-05 much, but I’ve experienced unexpected clove flavour from yeast a couple of times when using WLP002.
I went straight to the ‘wild yeast contamination’ explanation, but subsequent events cast doubt on the idea. Eventually I concluded it was more likely stress related mutations rather than wild yeast.

Us 05 is probably the most common homebrew yeast worldwide. If there's an infection with wild yeast, then there's usually also phenolic off flavour.

Of course the people scratch their head but it's way more likely that they all just caught an infection than us05 is causing the problem.

 

[rtstrider]

Did you happen to treat the water for chlorine or chloramines using campden?

 

[Bazza McKenzie]

Us 05 is probably the most common homebrew yeast worldwide. If there's an infection with wild yeast, then there's usually also phenolic off flavour.

Of course the people scratch their head but it's way more likely that they all just caught an infection than us05 is causing the problem.

I understand the point but the facts of many of these cases indicate something else. Probably still contamination with a pof+ strain but perhaps occurring at a point prior to the opening of the pack.

 

[Dland]

Did you happen to treat the water for chlorine or chloramines using campden?

No, I use untreated well water.

 

[Dland]

Re visiting this thread since I'm thinking about whether to dump some of this stuff or not. I made it though 1 keg out of four, beer OK, but I have lots more I like better. Have enough kegs so I can sit on this for a while, and it is changing over time, with clove taste becoming less sharp. Once I made a Belgium with BE-134 which was too clovey to enjoy, and I let it sit and it ended up tasting pretty good after a year.

Does anyone know the process of clove phenol breakdown, and what it breaks down into? Seems like I'm getting a stronger alcohol taste as the clove fades, but not sure if it is just ethanol.

Also, looking into clove phenol, it is reported to be toxic at high levels. In some cases phenols, though not specifically clove, may break down into benzene compounds, which doesn't sound that good.

Anyone remember enough organic chemistry to lend insight into this?

 

[An Ankoù]

I went straight to the ‘wild yeast contamination’ explanation, but subsequent events cast doubt on the idea. Eventually I concluded it was more likely stress related mutations rather than wild yeast.

If the yeast mutates then that means the genome has changed, doesn't it? So why can't part of that change affect the gene responsible for it being POF positive or negative? Either way, the mutated yeast has become, effectively, an infection. Just not an infection introduced from outside. It'll need to be eradicated and all the equipment disinfected just like any other infection.