Safale US-05 Cold Crash Caused Belgian Flavors

[JayDubWill]

I recently did a 10gal batch of Biermunchers world famous cream of three crops. I used US-05 yeast, re-hydrated and had active fermentation 12-16 hours later. I fermented at 62-64f for 14 days then cold crashed to 33f for 1 week. I then racked to secondary with gelatin and let it sit for another week at 33f. I always use star-san on everything that touches the wort post-boil and ferment in 6gal better bottles with air-locks.

I now know fermenting this yeast at the low end can cause peachy or apricot off flavors but what I ended up with is very estery and spicy with hints of clove. As a comparison this thing is a dead ringer for Fat Tire's Trippel and would give Victory's Golden Monkey a run for the money. Unfortunately having tried both of these Belgian style beers, I can tell you I don't much care for them.

The only thing I can point out as maybe the cause was the way I cold crashed. I use a temp controlled chest freezer and I crashed from about 64f to 32-33f in less than a day. Did I totally miss the concept of "cold crashing" and stressed the yeast out to the point of causing these off flavors? Could something else be the culprit? What's your experience with cold crashing with this yeast or others?

 

[Hammy71]

I've never had any issue using 05 at any temp between 60-72ish. Cold crashing is exactly what you described. I simply put my fermenter into a fridge, with no step downs at all. Hopefully somebody can chime in with some more advice on where to search for the culprit.

 

[JimRausch]

I agree, cold crashing is exactly as you described it. Also, the off-flavors produced by stressed yeast happen early in fermentation, not after everything is done. How was your initial pitch temp and early temp. control?
So, I'm lost too. Contamination? Mislabeled yeast?

 

[mbbransc]

I got a wild yeast contaimination at the end of summer that had Belgian characteristics. Really sucked too because I was brewing (2) batches at a time and had (2) brew sessions before I tasted my first bottle. All (4) batches had that flavor (2-IPAs, stout and blonde). I cleaned everything well, sanitized, and haven't had a problem since.

 

[RichBenn]

In the old days, beer in Belgium was fermented by blowing air over the wort. There was a natural occurring yeast in the air with that flavor. With the advent of air pollution, modern culturing and fermentation techniques were employed, as the air's yeast content was changing. So like the last post suggested, you could suspect wild yeast.

I had my first bad ferment in 30 years recently, with US-05. It reminded me of Belgium yeast, so wild yeast was a thought, but it could have been something else. I did pitch the yeast a bit high before fully cooling (which can cause esters in most yeast) and there was an overnight blow out that could have caused infection? I'll never know for sure what it was, and eventually threw out the beer.

Cleaned and sterilized, and paid better attention to the internal temperature during fermentations, kept careful watch on high gravity beers, and all my US-05 beers before and since have been clean and neutral. Note, I always try to keep the wort temp in the lower 60's to achieve this.

 

[JayDubWill]

wow, i'm really at a loss now. I pitched at about 72f since the ground water is just under that this time time of year (NW FL). I do brew and chill outdoors so wild yeast is a possibility. Just never had that problem before. I brewed another batch this past weekend, this time at my buddies house. We didn't hydrate the yeast this time, just pitched it directly, but just like last time, I have a strong fermentation going 12 hours or so since pitching. I'm going to ferment warmer at 68f and maybe slowly lower the temp while cold crashing a few degrees/day.

You know it just occured to me that the gelatin I used was pretty old...maybe it was harboring some nasties? I didn't boil the water, just did the bloom and microwave to 160f method.

 

[RichBenn]

wow, i'm really at a loss now. I pitched at about 72f since the ground water is just under that this time time of year (NW FL). I do brew and chill outdoors so wild yeast is a possibility. Just never had that problem before. I brewed another batch this past weekend, this time at my buddies house. We didn't hydrate the yeast this time, just pitched it directly, but just like last time, I have a strong fermentation going 12 hours or so since pitching. I'm going to ferment warmer at 68f and maybe slowly lower the temp while cold crashing a few degrees/day.

You know it just occured to me that the gelatin I used was pretty old...maybe it was harboring some nasties? I didn't boil the water, just did the bloom and microwave to 160f method.

Fermenting at a higher temp will not solve your problem. Normally, since the temperature rises during fermentation which means the wort temp is significantly higher than ambient, it's better to have lower temperatures during active fermentaion, then let it rise once fermentation is nearing completion, for cleanup.

You should always boil anything you put into your wort, then cool to the temperature to use. This is both for rehydrating yeast and for using water for adding gelatin. I don't see the need for gelatin either if you have used whirlfloc in the boil and/or are cold crashing. I always have clear beer; never used gelatin, or a secondary. Just more chances for infection.

 

[BigFloyd]

I cold crash all batches by simply moving the bucket 3ft from the fermenter fridge (usually finishing around 65-68*F for ales) over to the lagering freezer at 35*F. I've never had anything like the issue you've described, so I don't believe that your strange flavors were caused by a rapid cold crash of finished US-05.

 

[Surveyor06]

If you pitched at 72 degrees then maybe its possible that a bulk of your fermentation happened at a higher than optimal temperature. I know you said you use a chest freezer to control temp, but I would think that it might take a while to bring 10 gals of 72 degree liquid down to 64 degrees. I usually pitch at the same temperature that Im fermenting at. With US-05 thats typically around 63 degrees. Clove and apricot sounds like esters do to high fermentation temps.

 

[JayDubWill]

If you pitched at 72 degrees then maybe its possible that a bulk of your fermentation happened at a higher than optimal temperature. I know you said you use a chest freezer to control temp, but I would think that it might take a while to bring 10 gals of 72 degree liquid down to 64 degrees. I usually pitch at the same temperature that Im fermenting at. With US-05 thats typically around 63 degrees. Clove and apricot sounds like esters do to high fermentation temps.

That's a good point. Even though I split the batch into two 6gal better bottles it probably too it a good while to get down to 64. But were talking on the order of hours though not days.

 

[BigFloyd]

If you pitch a few degrees below your beginning target ferment temp, it won't be an issue.

 

[Surveyor06]

If you pitch a few degrees below your beginning target ferment temp, it won't be an issue.

I think that's true, but he said he said he had good fermentation going after 12 hours, so fermentation had started before that 12 hours. Off flavors from higher temps develop at the beginning of primary fermentation, by the time its over any off flavors you may have developed are present. From the research Ive done, US-05 likes to be in the lower to mid 60s. I'm not saying this is 100% the reason he got some funky flavors, but its the first thing that pops out to me. In any case, Ive done several batches with US-05 all pitched and fermented around 63, never had an off flavor. Just food for thought.

 

[BigFloyd]

I think that's true, but he said he said he had good fermentation going after 12 hours, so fermentation had started before that 12 hours. Off flavors from higher temps develop at the beginning of primary fermentation, by the time its over any off flavors you may have developed are present. From the research Ive done, US-05 likes to be in the lower to mid 60s. I'm not saying this is 100% the reason he got some funky flavors, but its the first thing that pops out to me. In any case, Ive done several batches with US-05 all pitched and fermented around 63, never had an off flavor. Just food for thought.

I agree with you 100%. I was just responding to the idea that pitching into warmer than ideal wort and letting it cool was always OK. I don't believe that it's a good practice as it can take some hours to get that amount of liquid to cool down (depending on your methods). I'd much rather delay the pitching of yeast to get the wort down into the 60-62*F range for US-05.

 

[JayDubWill]

I agree with you 100%. I was just responding to the idea that pitching into warmer than ideal wort and letting it cool was always OK. I don't believe that it's a good practice as it can take some hours to get that amount of liquid to cool down (depending on your methods). I'd much rather delay the pitching of yeast to get the wort down into the 60-62*F range for US-05.

I'm going to change the temp I pitch at to match my fermentation temp. After reading the article on BeerSmith about phenolics and tannins, i'm really thinking it was from bacteria from not boiling (and cooling) the water I used for the gelatin, or maybe it was the gelatin itself. Like I said it was an old (years old) pack. I've not read a single report about US-05 causing any of these Belgian-like flavors at any temp so I think it's sage to rule it out. My next batch is happily chugging along, other than not adding gelatin to this batch and fermenting at 68f I used basically the same method and recipe as before (pitched at about 72f) so it will be an interesting comparison.

 

[Gameface]

I think you're avoiding the real issue and cause of your troubles. You pitched hot. The issue becomes more than just cooling the liquid down. Now you have to tame an overactive fermentation. Fermentation is an exothermic process, and yeasts metabolism is driven by temperature. So, when you pitch hot the yeast are encouraged to throw off just the types of esters you're describing. As you cool the fermentation down the yeast are in overdrive trying to drive it back up. Sure, the chest freezer will win, but only after a certain amount of damage has been done.

Pitch cool (colder then your target fermentation temp) and let the wort naturally rise to temp and you'll be in control the whole time, not the yeast.

 

[Surveyor06]

I think you're avoiding the real issue and cause of your troubles. You pitched hot. The issue becomes more than just cooling the liquid down. Now you have to tame an overactive fermentation. Fermentation is an exothermic process, and yeasts metabolism is driven by temperature. So, when you pitch hot the yeast are encouraged to throw off just the types of esters you're describing. As you cool the fermentation down the yeast are in overdrive trying to drive it back up. Sure, the chest freezer will win, but only after a certain amount of damage has been done.

Pitch cool (colder then your target fermentation temp) and let the wort naturally rise to temp and you'll be in control the whole time, not the yeast.

Sounds like good advice here. Better to be at the low end of the recommended fermentation temperature during the entire duration of primary.

 

[Hopper5000]

Pitching a bit hotter can cause the yeast to stress out and make flavors like others have said. I would be careful, however, as the flavors you are describing could be a result of wild yeast as US-05 doesn't have those spicy characteristics.

 

[JayDubWill]

The temp range for this yeast is 59-75f. I don't know if I would call pitching at 72 "hot." At 80 or 90 I could see your point. Like I said earlier there are multiple accounts of people fermenting at the whole range of temperatures with this yeast and none that I've read are reporting the types of off flavors I experienced. That's why I was looking at something else as the culprit.

 

[BigFloyd]

The temp range for this yeast is 59-75f. I don't know if I would call pitching at 72 "hot." At 80 or 90 I could see your point. Like I said earlier there are multiple accounts of people fermenting at the whole range of temperatures with this yeast and none that I've read are reporting the types of off flavors I experienced. That's why I was looking at something else as the culprit.

Careful with advertised temp ranges for yeast. Yeast companies (and apparently people who print some kit instructions) have a vested interest in promoting the perception that a yeast will do okay at typical closet temps. Sure, they'll make beer, but with some rather undesirable flavors if used at the upper end of that range. Nottingham is a great example. Its stated range is 57-70*F, but it starts getting progressively more funky as the beer temp goes above 68*F. On the other hand, it'll ferment very cleanly at a couple degrees below it's supposed minimum.

Yeast can be sensitive little buggers when it come to temps. I've sampled other peoples' beers pitched and fermented at 70-72*F with US-05. They have a mild-moderate ester twang (which I don't like) that is absent from the cleaner-tasting brews done using the same yeast, but pitched at 60-62 and fermented at 64-65 during active ferment.

 

[Surveyor06]

Careful with advertised temp ranges for yeast. Yeast companies (and apparently people who print some kit instructions) have a vested interest in promoting the perception that a yeast will do okay at typical closet temps. Sure, they'll make beer, but with some rather undesirable flavors if used at the upper end of that range. Nottingham is a great example. Its stated range is 57-70*F, but it starts getting progressively more funky as the beer temp goes above 68*F. On the other hand, it'll ferment very cleanly at a couple degrees below it's supposed minimum.

Yeast can be sensitive little buggers when it come to temps. I've sampled other peoples' beers pitched and fermented at 70-72*F with US-05. They have a mild-moderate ester twang (which I don't like) that is absent from the cleaner-tasting brews done using the same yeast, but pitched at 60-62 and fermented at 64-65 during active ferment.

I agree. From the research I've done, 60-65 is the best range for us-05. The internet is filled with all kinds of information and hey, it's your beer, you can do whatever you like. But id bet that the flavors your seeing are from pitching at 72.

 

[rabeb25]

I have actually experienced this on my last 2 batches, but not the ones before that..

My regimen:
rehydrate yeast on stir plate pitch at 60f, ferment at 64 ambient, start raising temp 1 degree per day after about 3-4 days, until I get to 68. Ensure fermentation is over via hydrometer, then crash cool to 32f. Wait a few days, add gelatin and rack to keg.

As I said before my last 2 batches have a slightly fruity, slight clove DOMINENT flavor to them that was not there on racking. As this is my standard procedure for all my beers, and have been doing said procedure for many years...I am sort of baffled. I do think I purchased the us05 from 2 different stores, so maybe it is one store (midwest supplies), but not the other (lhbs). Or could be the knox gelatin, but again I have done this procedure literally hundreds of times before with not seeing these flavors.

 

[JayDubWill]

@ Gameface, BigFloyd, I do appreciate the feedback and will pitch at my fermentation temps from now on.

@rabeb25, we may be on to something. We have the yeast and gelatin in common, but my gelatin was very old so it's going to be different production date, lot #, etc. The yeast however I purchased from my LHBS about six weeks ago. I'm wondering if there's maybe a bad batch going around. Guess we'll have to stay tuned and see if the problem creeps up on anyone else using US-05 in the past month or so. The fruity flavor your describing is most likely from fermenting on the low end of the temp range with this yeast. I've read multiple accounts of people experiencing a peachy/apricot flavor when fermented at the lower temps. I was surprised I didn't encounter that myself, but it was probably overpowered by the phenolic/belgian/colve flavors I had going on. Interestingly enough I didn't taste it in any of my hydro samples either. It wasn't until I put it on gas and tried it a few days later.

 

[rabeb25]

I don't think so I have never gotten the peach flavors from my fermenting regimen with us05. This is more of a blueberry, and orange, with clove notes. Reminds me of a wit and a hefe crossbreed. These beers were a cream ale, and a blonde ale, so it really comes out. The weird thing is the last cream ale I did (I always keep one on tap, this new one was to replace that beer when the keg kicked), had absolutely none of that. I know for a fact the old cream ale was with yeast from a LHBS, and the other packs were from midwest, and were purchased probably 6 weeks ago as well.