US-05, pale ale and diacetyl. Ring a bell?

So, I'm officially giving up using US-05 for pale ales, and wondering if I should stop using it for any style.

I recently dumped a batch of APA because of diacetyl. It could not be missed, trust me. I'm sure you are wondering what I did wrong. Well, I have a standard brewing approach for ales that has been working for a long time. I make sure my pitch rate is adequate, sanitize well, oxygenate the wort, ferment steady at 68F for 2 weeks before kegging. I have made wonderful brown ales and stouts using US-05 under this same methodology, no problems with off flavors whatsoever.

Yesterday I was kegging a black IPA fermented with US-05 and I'm pretty sure I picked up diacetyl in the green beer. It's less than the dumped APA and I'm surely hoping it will be minimal once the beer is carbonated and conditioned but, I'm skeptical because I had become very sensitive to diacetyl.

I wonder if others have had similar experiences with this yeast. Thanks!

Indyking said:

So, I'm officially giving up using US-05 for pale ales, and wondering if I should stop using it for any style.

I recently dumped a batch of APA because of diacetyl. It could not be missed, trust me. I'm sure you are wondering what I did wrong. Well, I have a standard brewing approach for ales that has been working for a long time. I make sure my pitch rate is adequate, sanitize well, oxygenate the wort, ferment steady at 68F for 2 weeks before kegging. I have made wonderful brown ales and stouts using US-05 under this same methodology, no problems with off flavors whatsoever.

Yesterday I was kegging a black IPA fermented with US-05 and I'm pretty sure I picked up diacetyl in the green beer. It's less than the dumped APA and I'm surely hoping it will be minimal once the beer is carbonated and conditioned but, I'm skeptical because I had become very sensitive to diacetyl.

I wonder if others have had similar experiences with this yeast. Thanks!

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I haven't had any issues at all with S05 producing diacetyl. It sounds like you're doing everything right, but if you want to try again there is something that might help. That's just raising the fermentation temperature to 70 at day 5 of active fermentation. That would encourage the yeast to clean up any diacetyl they created.

One thing that comes to my mind is that diacetyl is sometimes produced by bacteria, like pediococcus. If you're using washed S05, that is a possibility. Otherwise, if you're using S05 straight from the package, and not having this issue with other strains, then I just don't know.

I trust you, but I've never gotten diacetyl from any of the 3 Chico strains. When exactly are you picking it up- when racking to kegs/bottles, after a few weeks of conditioning, during fermentation? Green beer often throws off interesting aroma and flavors, but nothing a week or two of cold conditioning can't fix (in my experience). Using WLP001 (same strain at US-05), I often go from grain to glass in 14-20 days, sometimes less with a low OG, and my beers some out crisp and clean. Hmm...

Yooper said:

I haven't had any issues at all with S05 producing diacetyl. It sounds like you're doing everything right, but if you want to try again there is something that might help. That's just raising the fermentation temperature to 70 at day 5 of active fermentation. That would encourage the yeast to clean up any diacetyl they created.

One thing that comes to my mind is that diacetyl is sometimes produced by bacteria, like pediococcus. If you're using washed S05, that is a possibility. Otherwise, if you're using S05 straight from the package, and not having this issue with other strains, then I just don't know.

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I currently don't have the ability to raise the room temp where I ferment but I thank your suggestion. I always use a fresh package and rehydrate before pitching. US-05 is my working horse... I keep a couple of packages in the fridge because its stable for a long time, it's cheap, easy to use, and have a clean profile. It will be a shame if I give up using it but I'm getting traumatized

Brulosopher said:

I trust you, but I've never gotten diacetyl from any of the 3 Chico strains. When exactly are you picking it up- when racking to kegs/bottles, after a few weeks of conditioning, during fermentation? Green beer often throws off interesting aroma and flavors, but nothing a week or two of cold conditioning can't fix (in my experience). Using WLP001 (same strain at US-05), I often go from grain to glass in 14-20 days, sometimes less with a low OG, and my beers some out crisp and clean. Hmm...

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In the APA the diacetyl flavor was strong since the beer was green upon kegging all the way to 2 months of cold conditioning. I had to dump it. Some off flavors are tolerable when subtle but diacetyl ruins it for me. I would rather have a bud light honestly.

For this black IPA I just legged it yesterday. Smell was clean but I picked up diacetyl on the green beer. Maybe this one will be ok once carbonated and conditioned. I hope.

Only time I really had a problem with diacetyl with US-05 was a DIPA that a pro brewer picked up on.. now every beer over a 1.050 OG, US-05 gets rehydrated and left on the cake an extra week.. that seemed to solve it for me..

I had this issues when I started brewing because I fermented too hot and didn't let the beer sit on the yeast cake for at least 2.5 weeks. Now I do 21 day primary fermentations every time 65F for the first week and then 70F for 2 more weeks, then bottle.

I use S-05 for most of my brewing (including an APA that I've brewed 4-5 times) and never had any issues. Like you, I tend to be pretty sensitive to diacetyl and once I find it in a beer that's all I can taste. I know this doesn't solve your problem, but I'm surprised you're having issues...

The yeast isn't the problem.

osagedr said:

The yeast isn't the problem.

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I have problems believing that when I have been using the same technique for ales and this problem is showing up only with this yeast.

Having said that, I do have a hand full of ales brewed with US05 that turned out great, so I'm really puzzled.

Looking back on my records of ales fermented with US05, the 2 that gave me diacetyl have only one thing different from the other successful ones. They both had an OG around 1.060 while the others were more around 1.050-54. I wonder if this yeast is getting "stressed" at higher gravities or perhaps 1 packet of rehydrated US05 is not enough for a 5 gallon batch of a 1.060 wort?

US-05 handled a 1.080 IPA just fine. I find it hard to believe the gravity caused THAT big of an issue. Could be wrong, though. I'm no pro.

You're on the boderline at 1.060 with one pack being enough (assuming near 100% viability).

Do you re-hydrate in sterile (boiled) water? This is a good practice.

As others have mentioned, it is not the yeast. The Chico strain is renowned for being a low diacetyl producer. I would re-examine sanitation and perhaps change out plastic tubing and maybe even get new bucket.

g-star said:

You're on the boderline at 1.060 with one pack being enough (assuming near 100% viability).

Do you re-hydrate in sterile (boiled) water? This is a good practice.

As others have mentioned, it is not the yeast. The Chico strain is renowned for being a low diacetyl producer. I would re-examine sanitation and perhaps change out plastic tubing and maybe even get new bucket.

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Interesting, this is a good thought. I just recently changed all my tubing but I do have many old plastic buckets I use as fermenters. I wonder if the 2 batches I had problems with were fermented using the same bucket. I don't keep track of that but I do fill buckets with starsan solution and let it act for several minutes, sometimes hours, before transferring the wort to it, so it should be sanitized unless this old bucket is hiding bacteria in some minuscule crevice inside?

I second raising temp after active fermentation is dying down. I always do this when the krausen has fallen. If you can't raise the temp in the room, try fermenting lower to begin with, a-la-swamp cooler, then remove it from the cooler on day 5 or so.

I had this problem twice using 05. The first time resolved itself after I warmed it and let it sit for 2 more weeks. The other I had to add a bit of sugar to get the yeast active again, that seemed to help it clean up. But I have used it many many times without any issue. I couldn't find the explanation.

Indyking said:

I currently don't have the ability to raise the room temp where I ferment but I thank your suggestion. I always use a fresh package and rehydrate before pitching. US-05 is my working horse... I keep a couple of packages in the fridge because its stable for a long time, it's cheap, easy to use, and have a clean profile. It will be a shame if I give up using it but I'm getting traumatized

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Is your ambient 68*? If so then your fermentation temp could be anywhere between 72-78 which would produce diacetyl with wlp001/us-05, to the point where it wouldn't clean up. I have used us-05 in those ranges and got a very buttery beer, I ended up letting it age for a while and dry hopping and did a pretty good job covering it up.

Can you get your temps lower than 68*? I usually ferment US-05 at a fermentation (not ambient) of 62-65 using a swamp cooler, and all my beers come out pretty clean. I also use Notty and let it ride at 60* and I am pretty happy with the results too.

I'm inclined to believe that your issue may be temp related. In your original post, you said that you ferment steady at 68f for 2 weeks. You also indicate that you don't have the ability to increase the temp of your fermenter near the end of fermentation. So a couple of questions:

1. What are you using to gauge your fermentation as a steady 68f? Are you measuring the temp of the fermenting wort? measuring ambient temp? Just reading the setting off your room AC control?

If you're not measuring your fermenting wort, you may actually be fermenting at a different temp than you think. Also, if you're relying on the ambient room temp, that will often fluctuate depending on the room's position in the house, weather, time of day, etc. I am thinking temp control may have bitten you but will need more info about how you're set up and how you're determining fermenting temp to be sure.

2. When you say you're fermenting for 2 weeks (and I apologize if you already said this and I missed it) are you staying in your primary the whole time or are you moving to a secondary at some point?

It sounds like the 2 problem beers were in excess of 1.060 and you may have under pitched slightly with only one packet. If the yeast was a bit stressed by being at the max end of its capacity, that could cause it to throw off flavors. If you moved into a secondary, transferring off the bulk of the primary yeast cake, it could have made the diacetyl issue worse by not leaving enough yeast in your beer to clean it properly.

I use us05 almost exclusively unless I am going for a specific yeast profile (British. Belgian, etc.) I always rehydrate and anything 1.060 or higher gets 2 packs. Essentially I just follow mrmalty.com.

The only off flavors I've ever had with it are from acetaldehyde. And I traced that one back to temperature. I had just started to ferment my ales in a fridge with a temp controller and was pulling them off the yeast before all of the off flavor compounds ha been cleaned by the yeast

I just had diacetyl in a us-05 batch of Oktoberfest. I couldn't figure out why either as I've used the strain many times. Looking back, my og was 1.062 I think, so maybe it does have to do with higher gravity worts.

Mine has subsided a lot with conditioning, but its not gone.

Maybe in the future, I'll use more than one pack on higher gravity beers to see if that helps.

Thanks for all the responses. I think I know my basics of brewing and have about 30 batches of experience with just 2 diacetyl problems, both with US-05. My standard ale technique was applied to both problematic batches:

1- My ambient temp was steady at 68F in the cellar.
2- The wort was cooled down to 68F before pitching.
3- I used a infrared thermometer to measure the surface temp in the plastic bucket. I find that more accurate than the temperature strips. The wort rose to 71.6 maximum during peak fermentation and hover around 70F in early/late fermentation stages. That is the typical temperatures I was successful before with other batches of US-05.
3- I left 2 weeks in the fermenter (no secondary) and transferred directed to a keg for carbonation/conditioning. That approach works great for my ales. After the beer is cooled in the keg, the remaining yeast tends to accumulate near the dip tube, so I just pour about half a pint to get rid of the yeast. My beers tend to be very clear with that method.

I was doing some reading last night in other forums and was glad to know that the issue with diacetyl with US-05 pops up everywhere I looked at. I'm inclined to think it was a problem of the high gravity (1.060) but there are brewers here and elsewhere reporting good results with 1 packet brewing as high as 1.080, so I'm still not sure.

Indyking said:

Thanks for all the responses. I think I know my basics of brewing and have about 30 batches of experience with just 2 diacetyl problems, both with US-05. My standard ale technique was applied to both problematic batches:

1- My ambient temp was steady at 68F in the cellar.
2- The wort was cooled down to 68F before pitching.
3- I used a infrared thermometer to measure the surface temp in the plastic bucket. I find that more accurate than the temperature strips. The wort rose to 71.6 maximum during peak fermentation and hover around 70F in early/late fermentation stages. That is the typical temperatures I was successful before with other batches of US-05.
3- I left 2 weeks in the fermenter (no secondary) and transferred directed to a keg for carbonation/conditioning. That approach works great for my ales. After the beer is cooled in the keg, the remaining yeast tends to accumulate near the dip tube, so I just pour about half a pint to get rid of the yeast. My beers tend to be very clear with that method.

I was doing some reading last night in other forums and was glad to know that the issue with diacetyl with US-05 pops up everywhere I looked at. I'm inclined to think it was a problem of the high gravity (1.060) but there are brewers here and elsewhere reporting good results with 1 packet brewing as high as 1.080, so I'm still not sure.

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Thanks for the additional info. Sounds like you may be leaning toward gravity plus pitching rate as a likely culprit. As for those who have said they pitched a single packet into huge volumes with great results, I guess it's possible but it's still a gamble. Scaling your pitching rate to the gravity and volume of you wort is always a good idea. And it helps swing the odds of winning that gamble in you favor.

You could always test it. If you kept thorough notes on one of the diacetyl batches, you could do it again, sticking as close as possible to your steps from last time. Only this time, pitch 2 packets.

If you don't get diacetyl, it's not a clear indication that pitching rate was the issue. but at least you'd have a good beer on your hands If you get diacetyl again, it at least eliminates one more potential cause.

US-05 tends to be very clean for me and most I've seen post and talked with.
You do have to treat it well, like all other yeast strains.
I'd like to see your detailed notes on your entire brewing and fermentation process, including sanitation, before I'd blame it on the yeast. How about giving those to us so we can see?
Temp control, pitch rate, poor fermentation practices, and infection all come to my mind when I hear diacetyl and this yeast strain.

FWIW, a buddy in my brew club had the same diacetyl experience with S-05 recently. He's been brewing for 8 years, has temp controlled SS conical, etc. Strange!

might there be the chance that there's a batch of S-05 circulating at the moment that's just not quite up to par??

I'm not a professional but, like I said before, I have considerable experience brewing, over 30 AG batches. I'm very strict with sanitation. I cannot prove it but I can say that chances I got the batches with diacetyl contaminated are slim. Yes, my plastic buckets could use use some retirement right now and I'm thinking about moving to all glass since I can't yet afford conicals, but how come I never got contamination with all the other batches using these same buckets? Temperature was ok, 71F for the actual wort is near the maximum I like but don't think was warm enough to produce diacetyl. I did use just one rehydrated pack in a 15P wort (1.060) so maybe it was under pitching, but I'm not completely buying that either. Fermentation behaved as usual, got airlock activity in less than 6 hours after pitching and peaked with 24-48 hours. It also attenuated in the range I'm used for this yeast, it went from 15P to 7.6 (76% attenuation). Maybe I got a bad lot of the yeast? I expect Fermentis to have a robust QC process but you never know. Bad things happen sometimes.

Just an update. The beer is still green but it's now 1 week under CO2 and its almost fully carbonated. I was hoping the diacetyl would fade away a bit but it is tasting quite the opposite. It's even stronger now in the carbonated beer. I will have to dump it when in need for that keg. This beer came out all wrong anyway, it was supposed to be a black IPA but its brown despite of what beersmith tells me and the hop character did not come out quite right. I also found more people and other threads in beer forums reporting problems with diacetyl by using US-05 without any apparent reason. I'm not saying the fault was at the yeast and not on anything in my process, but considering my experience so far, I'm not willing to take any risk of using this yeast anymore.

No problems here at all. Why not let the beer ferment longer? 2 weeks, in my experience, is a little short. Another week might clear it up. I do 3 weeks or longer myself. I do control the temperature - 62-66 for 3 weeks then a couple of days at 68+, the I cool it to 35-40 before kegging.

FWIW and YMMV and WTF etc.

Steve da sleeve

stevedasleeve said:

No problems here at all. Why not let the beer ferment longer? 2 weeks, in my experience, is a little short. Another week might clear it up. I do 3 weeks or longer myself. I do control the temperature - 62-66 for 3 weeks then a couple of days at 68+, the I cool it to 35-40 before kegging.

FWIW and YMMV and WTF etc.

Steve da sleeve

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2 weeks had always worked for me.

could always pitch some brett and lit it scarf all of that tasty diacetyl.

If you're done with this yeast I'll take any extras off your hands. It would save me the $3.99 each. I doubt the diacetyl is going anywhere now if the beer is off the yeast cake, but we can hope age will help.
Cheers.

Yes but lots of cleaning up happens after fermentation is over. 2 weeks clearly hasn't worked for you in this case. This is my point, take it or leave it.

Steve da sleeve

dryboroughbrewing said:

could always pitch some brett and lit it scarf all of that tasty diacetyl.

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Yes, but adding fermentables to reactivate the yeast after fermentation is complete not always eliminate yeast by products, depending of the cause it may make it worse or create other off flavors. I did not want to waste more time with it.

stevedasleeve said:

Yes but lots of cleaning up happens after fermentation is over. 2 weeks clearly hasn't worked for you in this case. This is my point, take it or leave it.

Steve da sleeve

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We don't know that. How can I blame in the 2 weeks for one batch with diacetyl while I have 37 others on file that I fermented for 2 weeks and had no problems with diacetyl?

pdxal said:

If you're done with this yeast I'll take any extras off your hands. It would save me the $3.99 each. I doubt the diacetyl is going anywhere now if the beer is off the yeast cake, but we can hope age will help.
Cheers.

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Fortunately I don't have any left in stock! I have been told diacetyl does not go away with aging. Not really willing to waste a full keg for months to find out.

Look up diacetyl rest.

I should add that I'm not a strong advocate of long fermentation, I know it works for a lot of people here. In have tested same recipes with different fermentation times and noticed no improvement beyond 2 weeks for ales. In fact I find strong Belgian ales to taste more characteristic of the style with even shorter time, typically 10-12 days of fermentation.

stevedasleeve said:

Look up diacetyl rest.

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Dark IPA is an ale. Yes, I do d-rest for lagers obviously.

I've got an APA that is exhibiting some buttery notes now, as well. OG 1.054, FG 1.012, three weeks from brew day to bottling, three weeks since bottling, temp on fermometer never got above 72. So it might just be a batch of yeast.

MrOH said:

I've got an APA that is exhibiting some buttery notes now, as well. OG 1.054, FG 1.012, three weeks from brew day to bottling, three weeks since bottling, temp on fermometer never got above 72. So it might just be a batch of yeast.

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I know it's easy to blame in the yeast, but based on what I have seen with this yeast and all the information I got, I'm inclined to think some lots of this yeast have a diacetyl liability.

The first few times I used US-05 I was fine but then I had a few with diacetyl I tried to warm up and do a diacetyl rest @ 68-70 for a few days. But it didn't help.
I even went as far as to split a batch up and pitched Nottingham ale yeast on 2.5 gallons and US-05 on the other half. I will be using Nottingham or S-04 from now on when I buy dry yeast. Some will swear up and down that the yeast isn't the problem but for me it made all the difference when I tried another yeast. To each his own but for now I'm not going to be putting US-05 in my wort.

It seems like you made up your mind the problem was the yeast well before you first posted this thread.

While it's possible that the yeast is the culprit, it's far more likely a process issue. Diacetyl is often caused by yeast stress. If you are underpitching, which it sounds like you might be, and under-aerating, that's a stressful environment likely to cause diacetyl and other off flavors.