IPA off flavors...Again!

[Mountainsax]

My temp controller is good to +/- 1 degree. I'm pretty sure that means if I set it at 67, the fridge will kick on at 68 and cool down to 66 before shutting off. I realize that without a thermowell I'm reading a temp that is the outer edge of the beer/fridge ambient. The foam insulation helps keep the fridge ambient temp at bay. Eventually I'd like a thermowell, just not in the budget/plan at the moment.

It's not perfect, but I think it's good enough for me!

 

[Mountainsax]

So if we assume the off flavors are from the yeast, either being stressed or fermenting at a low temp, how do I fix this batch?

I know time is your friend and it should mellow out as it ages. Would it be better to keep the keg in the kegerator (36 deg), put it back in the germ fridge (64-66 deg) or move it into the house (65-70 deg)?

 

[m00ps]

If the beer does indeed need to condition to age out the flavor, this will happen the fastest at room temps

 

[k1ngl1ves]

The fastest shortcut to poundtown is to go downtown...unless the red line is in service. If that's the case just stay home.

Fastest way is with a prepaid ticket...

 

[joshesmusica]

I agree all chemical reactions will happen quicker at room temps. When you say banana, that's clearly an ester, and that won't age out. If you're getting banana from us-05, then you're yeast are stressed, or they were not viable to begin with, or you waayyy under-aerated. I would also suspect direct sprinkling, but others attest no off flavors ever, but I tend to think they're likely masking those off flavors with tons of hops, which you didn't get.

 

[Schecter]

Are you sure you are tasting esters? Lots of flavors are going on in your IPA and US-05 should ferment relatively clean at your temperature.
Do you know what your water chemistry is like? I ask because of your "astringent" and "alcoholic" flavor. I confused my off flavor to be fusel-alcohols for the longest time, suggesting I was fermenting hot. In the end, it was chlorine in my water. Since cleansing it, my IPAs have been off the charts.
Others have had experience with berries and whatnot from US-05, I have not, and I ferment within your range as well. The caramel can add sweetness and combined with your dryhop, it may produce your berry flavor. Tricky, because time could mellow your off- or unintended flavor, but it also kill your aroma in your IPA.

 

[beerkench]

So if we assume the off flavors are from the yeast, either being stressed or fermenting at a low temp, how do I fix this batch?

I know time is your friend and it should mellow out as it ages. Would it be better to keep the keg in the kegerator (36 deg), put it back in the germ fridge (64-66 deg) or move it into the house (65-70 deg)?

Take the keg out, throw in a hop sock with +2 oz, and leave for week at room temp. All will be good!


Sent from hell
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[beerkench]

If you're fermenting cold, it's good to let the temp rise a few degrees mid fermentation so that the yeast gets a bit busier and cleans up.


Sent from hell
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[Mountainsax]

Are you sure you are tasting esters? Lots of flavors are going on in your IPA and US-05 should ferment relatively clean at your temperature.
Do you know what your water chemistry is like? I ask because of your "astringent" and "alcoholic" flavor. I confused my off flavor to be fusel-alcohols for the longest time, suggesting I was fermenting hot. In the end, it was chlorine in my water. Since cleansing it, my IPAs have been off the charts.

I'm not great with off flavors yet, still learning. Eaters are the best I can guess based on the common off flavors and their descriptions. The water was filtered water from the machines at Albertsons.

 

[Gavin C]

I'm going to suggest an opposing idea.

I'm guessing 64F was your ambient temp and you did not accurately monitor your beer's temperature.

64 ambient will likely lead to a ~72F fermentation temperature for s-05. Too warm for my tastes and likely result would be the production of Isoamyl acetate (banana aroma).

If 64 was indeed the beer temps then I could simply be a result of the overly long fermentation. 6 weeks seems needlessly long. But to be fair, I'm clutching at straws if my original theory gets shot down.

 

[joshesmusica]

We use a ferm fridge with temp controller. No thermowell, the probe is on the side of the fermenter stuck down a little notch in a piece of foam insulation that is strapped onto the carboy.

I'm going to suggest an opposing idea.

I'm guessing 64F was your ambient temp and you did not accurately monitor your beer's temperature.

64 ambient will likely lead to a ~72F fermentation temperature for s-05. Too warm for my tastes and likely result would be the production of Isoamyl acetate (banana aroma).

If 64 was indeed the beer temps then I could simply be a result of the overly long fermentation. 6 weeks seems needlessly long. But to be fair, I'm clutching at straws if my original theory gets shot down.

I don't think this is the case, Gavin. From the way he describes it, it's almost the same set-up as yours.

But I do agree, and as I stated earlier, that the banana flavor is that specific ester that you named. I don't think it can come from anywhere else. Interestingly, white labs did a gas chromatography test with the same wort and yeast (wlp001), but one batch was fermented at 66F, the other at 75F. In both cases, the isoamyl acetate was well above the perception threshold (70 ppm). At 66, it was at 108 ppm. At 75, it was at 114 ppm.

Causes of esters increasing:
1) Increasing the OG. Higher OG means more yeast growth which means more esters produced.
2) Decrease of lipids. If you're trying to get the clearest beer possible into the fermentor, combined with low aeration, you will actually increase ester production.
3) Decreasing aeration. Again this typically has to be in combination with a decrease of lipids, as the lack of oxygen can sometimes be overcome by an increase in lipids.
4) An increase in zinc. This is likely only gonna happen if you've overdone the amount of yeast nutrient added.
5) Increase in temperature. Likely not the case, in this particular instance.
6) Constant agitation/stirring throughout fermentation. Again not the case here, but a reason why it's a good idea to cold crash, and then decant, the starter.
7) A lack of any head pressure. Open fermentation basically. Not the case here either.
8) A decrease in pitching rates. If rehydration went awry, or one package wasn't enough for the OG, then more esters will be formed because of more yeast growth.

OP, I don't know what you've done wrong here with this beer. BUT if you're getting the banana flavor, as you said you were very early on in this thread, then you need to look at these factors. It seems you've got temperature control down, so I would be looking to your rehydration method, and your pitching rates according to your OG. Also, allowing a bit of the trub into the fermentor will help overcome under-aeration, as I mentioned. Under-aeration is a very common problem at the homebrew scale, but often times we make up for it by having a lot of trub make its way into the fermentor.

I will say, though, that those esters (particularly if you combine banana with berry) often remind me of bubble gum. I wouldn't say I can always detect every flavor compound, but for some reason I'm particularly sensitive to esters. I will often taste esters present in a beer when others don't notice it at all. If you're really wondering exactly how esters taste go buy yourself a Tank 7 from Boulevard, or a Hefeweizen. It could very well be that you're overly sensitive to these compounds. But another thing that goes along with the white labs test I mentioned, and I made this point in an earlier post, it's likely that most people using US-05 are producing major hop bombs and covering up all those esters. But in this case, you went a little low on the dry hops. Increase your late-boil hops and your dry hops in the future, and address those problems I showed you here, and you'll likely fix this problem.

 

[Mountainsax]

Awesome write up josesmusica!!! Thanks for taking the time to put this together for me. I just stuck the temp probe in my ferm fridge directly into the batch I'm fermenting now and the difference was only 0.3 deg F.

 

[gwapogorilla]

Getting fruity esters, banana and berries maybe? Poured a second 1/2 pint and there was less ester aroma, maybe slightly less flavor too. Still very in your face though.

Might have a bit of astringent or alcoholic flavor too... Anyone live in Durango that knows what they are tasting who wants to come try it!?[emoji39]

It sounds like the yeast to me. Specifically, stressed yeast. Make yeast starters....always, always, always.

 

[Mountainsax]

It sounds like the yeast to me. Specifically, stressed yeast. Make yeast starters....always, always, always.

I think that is definitely the plan!

 

[beerkench]

I think that is definitely the plan!

From what I have read there is no need to do a starter with dry yeast. It also specifies on the Safale website that aeration is not necessary with their dry yeasts due to the yeast having all they need to reproduce, locked in during the drying process (can't remember what but it was something to do with the sterols)



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[kombat]

So either don't rehydrate US-05 or use a liquid yeast (Wyeast 1056) and make a starter.

I would recommend that you always rehydrate dry yeast according to the manufacturer's instructions. Pitching dry yeast directly into the wort can reduce cell viability by up to 50% (Source: "Yeast", White/Zainasheff). If you account for this reduced cell viability by pitching more yeast, then that's fine, but you're just wasting your money by killing half the yeast you're paying for.

 

[joshesmusica]

Awesome write up josesmusica!!! Thanks for taking the time to put this together for me. I just stuck the temp probe in my ferm fridge directly into the batch I'm fermenting now and the difference was only 0.3 deg F.

Meh, I got it all from the book that Kombat just mentioned, which I'm now on my second round of reading it. I highly recommend that whole series: Hops, Yeast, Malt, and Water. There's tons of info in those, so much so, that I'm reading each one a couple of times to try to absorb it all while I continue applying what I'm learning with each new brew day.

 

[Mountainsax]

Some of this has been said before, but here is a direct quote from Fermentis:

Rehydration instructions:
Sprinkle the yeast in minimum 10 times its weight of sterile water or wort at 27°C ± 3°C (80°F ± 6°F). Leave to rest 15 to 30 minutes.
Gently stir for 30 minutes, and pitch the resultant cream into the fermentation vessel.
Alternatively, pitch the yeast directly in the fermentation vessel providing the temperature of the wort is above 20°C (68°F). Progressively sprinkle the dry yeast into the wort ensuring the yeast covers all the surface of wort available in order to avoid clumps. Leave for 30 minutes, then mix the wort using aeration or by wort addition.

We have not been giving the dry yeast as much time to re-hydrate as recommended.

I have been looking into yeast a lot lately and have seen the same thing beerkench mentioned. Dry yeast doesn't need a starter, but re-hydrating is beneficial. Oxygen is used by the yeast during the reproductive stage (primarily). If you pitch enough yeast then the oxygen levels in the wort are not as important. Recommended oxygen levels are around 10ppm, and shaking the fermenter can get you to about 2-5ppm.

I still have a lot to learn, but this has been super helpful. Thanks to everyone for your input and insight!

 

[Mountainsax]

Meh, I got it all from the book that Kombat just mentioned, which I'm now on my second round of reading it. I highly recommend that whole series: Hops, Yeast, Malt, and Water. There's tons of info in those, so much so, that I'm reading each one a couple of times to try to absorb it all while I continue applying what I'm learning with each new brew day.

Those books are definitely on my Christmas list!

 

[j1n]

It's getting deep in here. I ferment US05 at 66-67. Also it took me a little experimentation to realize that setting my temp controller to 67 doesn't mean it holds my booze at 67 degrees. It means the fridge kicks on at 67, so most of the time it stays a degree or two cooler than the temp I set the controller to. Make sure you're factoring that in when choosing your temp.

Why dont you put the temp probe to the side of the fermentor and insulate it? Or you can get a thermowell. My temp probe reads the wort temp not the air temp. why play that guessing game when its easily mitigated with a foam pad to insulate.

 

[joshesmusica]

Why dont you put the temp probe to the side of the fermentor and insulate it? Or you can get a thermowell. My temp probe reads the wort temp not the air temp. why play that guessing game when its easily mitigated with a foam pad to insulate.

Please read the entire thread...

 

[joshesmusica]

Oxygen is used by the yeast during the reproductive stage (primarily). If you pitch enough yeast then the oxygen levels in the wort are not as important.

This isn't necessarily true. In a starter, the reason why people use a stir plate is that the oxygen helps with yeast growth (reproduction). But in a normal fermentation the yeast will uptake all of the oxygen available in the wort within the first 30 mins of inoculation! They use it to build up their cell walls, which of course helps with reproduction, but they won't constantly use up the oxygen throughout the fermentation.

Proper pitch levels of vital and viable yeast can surprisingly overcome some things, but not when the Brewer starts compounding mistakes. So it's one thing that is often discussed with brulosophy experiments: if you mess up just one variable, it's not likely to make a huge difference. But if you're getting off flavors at then there's obviously either an extreme issue with just one variable, or you're compounding a few mistakes on top of each other.

 

[beerkench]

This is from the Danstar website: 'Most commercially produced Active Dry Beer yeast actually require no O2 addition for a successful average gravity wort fermentation. There is enough lipids built into the cell at the yeast factory.'

 

[kombat]

It also specifies on the Safale website that aeration is not necessary with their dry yeasts due to the yeast having all they need to reproduce

That's possibly true, but it presumes you're pitching enough cells to minimize the need to reproduce. And if you're dry-pitching a packet of yeast, you're underpitching. Combined with inadequate aeration/oxygenation, that's a recipe for stressed yeast and off-flavours.

The one time I actually tried pitching (rehydrated!) US-05 without any aeration whatsoever, the batch become a banana-flavoured dumper. I now aerate every batch, regardless of whether I'm using dry or liquid yeast.

 

[Mountainsax]

From what I have read it is impossible to over aerating by shaking (which is what I do) and certainly can't hurt. The plan moving forward is to be very kind to the yeasties, properly re-hydrate dry yeast according to the instructions from Fermentis, likely avoid US-05 when possible, do a starter with any liquid yeast, and make sure I pitch enough for anything over 1.060 OG!

I'm going to stick with fermenting temps in the middle of the ideal range for each yeast through primary, then bring it up a couple degrees for "secondary" (whether it is in a different vessel or not).

 

[skitter]

I actually like US-05 as a yeast, I am pretty stuch to dry yeast as my budget is minimal. I have tried S-04 and US-05, S-04 I am not a fan of the aftertastes, so now I pretty exclusively use US-05 in all my beers.

I use half a packet for each of my batches (2.5G Batch) and all I do is boil 1/2c water, add a couple sterile ice cubs and add yeast, let sit while I am cooling my wort, then pitch once it's in the fermenter.

Fermentation for me is usually 2 weeks, unless I'm over 7% (still don't own a hydrometer...) and I havn't had any big bombs yet. Fermentation is achieved in my chamber set to 18c (Chinese controller), and the thermometer strip on my keg reads 65 degrees F through the entire process.

I havn't had any fruity flavors, and US-05 is generally good for the profile of the beers I brew (Malt Forward, not a hophead). Only time I get weird flavors is with various other yeast strains. US-05 has been my workhorse for about 2 years now of AG brewing.

 

[Jim311]

Why dont you put the temp probe to the side of the fermentor and insulate it? Or you can get a thermowell. My temp probe reads the wort temp not the air temp. why play that guessing game when its easily mitigated with a foam pad to insulate.

That's exactly what I do.

 

[Mountainsax]

This batch may be a lost cause. I pulled the hops and put the beer back on CO2 the other night. It wasn't carb'd yet but I had to pull a little taste to see what was happening. It is still pretty bad, maybe even worse than before (if that's possible). I'll let it sit for a couple weeks and see if it mellows out. Sigh...

 

[kombat]

Probably stressed the yeast. To provide a better guess, we're going to need a lot more details about your process.

 

[Mountainsax]

It's a sad, sad day. [emoji29] A moment of silence please.
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