off flavour?

[Brewsta]

g'day all,
got an off flavour in one of my brews that i just can't put my taste buds on.

it was an all extract brew, APA style, 23ltrs brewed at 18 deg C under temperature control for 3 weeks.


1.5kg can of Coopers Liquid Light Malt Extract

1.5kg of Coopers Liquid Wheat Malt Extract

500g of Carahell (steeped for 30 mins)

250g of Coopers BE1

45g Amarillo

45g Nelson Sauvin

1x 11.5g satchel of Fermentis US-05 Dried Yeast

hop additions

Bitterness - @ 60 minutes 15g of Amarillo, 15g of Nelson Sauvin

Flavor - @ 20 minutes, 15g of Amarillo, 15g of Nelson Sauvin

Aroma - @ 5 minutes 15g of Amarillo, 15g of Nelson Sauvin

​i knew when i kegged it that it didn't smell normal, it sort of reminded me of the smell i used to get when i brewed at high temperatures before i had temp control. 28 - 30 deg C. It's a cross between a yeasty / chemical flavour that really hangs on to your tongue and very bitter, very off putting, enough to make you spit it out. Smell is almost like some sort of burnt aroma (although no scorching occurred). there was no white film on top of the wort to indicate infection, but i'm wondering if it still could be? never had one so unsure what it would taste like. All i know is i can't swallow it. Ingredients were pretty fresh, so have confidence in them, was thinking DMS but doesn't really fit with sweet corn flavour? had something similar to this once, aged it for 2yrs kept trying it every now and again along the way but the flavour never went away. any ideas?

thx.

p.s. this i a brew i have done for a few years, although i do muck around with the hop additions sometimes. but generally turns out pretty good for an extract brew.

 

[Killer Brew]

Would you describe the chemical flavour as medicinal or bandaid type?

 

[MHB]

Sounds like Yeast Autolysis is a good bet, I know I'm in the minority on AHB but any brewing text will tell you not to leave beer on the yeast for more than 14 days, you should rack if want to leave it longer than that.
Infection of one sort or another is possible to.

This is a free resource, worth putting it on your desk top, I use it regularly, just Ctrl F to search for anything you can think of that you or anyone else can smell, will probably give you a few good ideas. View attachment Complete_Beer_Fault_Guide.pdf
Mark

 

[Brewsta]

Would you describe the chemical flavour as medicinal or bandaid type?

no, not really, maybe more like boiled potatoes that have been burnt on the bottom of the pan if that makes sense?

Sounds like Yeast Autolysis is a good bet, I know I'm in the minority on AHB but any brewing text will tell you not to leave beer on the yeast for more than 14 days, you should rack if want to leave it longer than that.
Infection of one sort or another is possible to.

This is a free resource, worth putting it on your desk top, I use it regularly, just Ctrl F to search for anything you can think of that you or anyone else can smell, will probably give you a few good ideas.

Complete_Beer_Fault_Guide.pdf
Mark

WOW..thanks for that..it's a very in depth guide just what i need, thanks! i'll have a read and post back.

FYI - i have actually left the same style brew for 5-6 weeks, no problem & no off flavours, ultra clear brew though. Not that i'm saying it's the right thing to do, but i generally leave my brews for about 3 weeks (under temp control) for better clarification. Maybe i'm not so lucky this time huh? i'll take what you've said onboard and maybe try next brew.

 

[Droopy Brew]

I've had autolysis before (cooked the yeast on the heated stir plate by mistake). Very strong vegemite/beef flavour and aroma. It is unmistakable.

IF it is a phenolic type smell/flavour which can present as burnt rubber or bandaid I would be looking at yeast stress from a large under pitch.

If you still have the yeast packet floating around check the date because a packet of properly treated and fresh US05 in that brew should be close enough to reasonable pitching rate.

 

[Brewsta]

i love vegemite & beef, there up there with beer…..but no it doesn't smell or taste like that.

After having a read of Mark's attached guide, i'd have to say it was a bit of both Papery (Oxidisation) & cooked potato (Methionol - infection).

I'll have to think about how this could of happened, oxidisation - i guess must be due to what i did on the day, infection however i'm leaning to a dodgy keg seal as i know i have trouble with the lid on one keg.

Mark, interestingly in the guide for autolysis, its says "to avoid" remove from the yeast cake 2-4 weeks, so i should be pretty safe with 3 weeks yeah? (3 weeks also works with my keg rotation) I can't say i have ever detected those flavours in my brews since going to temperature control. maybe before then though yes.

 

[MHB]

If in fact flavour from yeast autolysis was the only reason to get beer off the yeast cake then you might be right and it would be "safe" to leave for 2-4 weeks.
But (and there is always a but) tasting like burnt car tyres isn't the only reason we should get beer off the yeast, if there was no risk at 4 weeks, I'm sure the author would have said get it off before four weeks, he isn't there is some chance of off flavours at 2 weeks.
Bit like playing Russian Roulette, at 1in6 the odds sound pretty good, add an extra bullet, 2in6, 3in6 well that's 50/50, you would have to be desperate and playing for very high stakes.

There are a bunch of other reasons, like the production of head destroying Protease A, Oxidative reactions...
Buy another fermenter and rack at the end of ferment (when you hit FG), frankly if the yeast isn't finished work in 7 days you underpitched/haven't aerated well/have a poor nutrient profile in your wort... all of which can also contribute to other off flavours.

 

[TheWiggman]

From what you're saying you've done this brew before a number of times and nothing in your process has changed. That really narrows it down to two things -

1. Issue with ingredients
2. Infection

Check the pressure on it and put it aside. If the pressure increases you can be sure it's an infection. If not, possibly a fermentation byproduct you're not after but also possibly an issue with ingredients like improperly handled yeast, poorly stored grains etc.

 

[warnerbrew]

Sounds like Yeast Autolysis is a good bet, I know I'm in the minority on AHB but any brewing text will tell you not to leave beer on the yeast for more than 14 days, you should rack if want to leave it longer than that.
Infection of one sort or another is possible to.

This is a free resource, worth putting it on your desk top, I use it regularly, just Ctrl F to search for anything you can think of that you or anyone else can smell, will probably give you a few good ideas.

Complete_Beer_Fault_Guide.pdf
Mark

Thanks for the reference guide Mark - very good.

 

[Zorco]

If in fact flavour from yeast autolysis was the only reason to get beer off the yeast cake then you might be right and it would be "safe" to leave for 2-4 weeks.
But (and there is always a but) tasting like burnt car tyres isn't the only reason we should get beer off the yeast, if there was no risk at 4 weeks, I'm sure the author would have said get it off before four weeks, he isn't there is some chance of off flavours at 2 weeks.
Bit like playing Russian Roulette, at 1in6 the odds sound pretty good, add an extra bullet, 2in6, 3in6 well that's 50/50, you would have to be desperate and playing for very high stakes.

There are a bunch of other reasons, like the production of head destroying Protease A, Oxidative reactions...
Buy another fermenter and rack at the end of ferment (when you hit FG), frankly if the yeast isn't finished work in 7 days you underpitched/haven't aerated well/have a poor nutrient profile in your wort... all of which can also contribute to other off flavours.

Hi Mark,

With lagering, and using lager yeasts, does the above modify in some way? Are autolysis rates decreased with the lower temperatures of lagering?

 

[MHB]

Err well yes, maybe...
The 14 day recommendations comes from references like Kunze and presuppose perfect wort properly aerated, pitch at brewery optimum rates in the best temperature controlled CCV fermenters money can buy and brewing as cold as you (reasonably) can.

So yes I suspect that 14 days is a safe upper limit before "Measurable Harm" can be detected, if you don't have a million dollar brewery with professional brewers and laboratory support it represents a (probably) safe upper limit, not one you should be thinking of exceeding.
Posted this before but this is a temp/time for a commercial lager production that best matches what home brewers may be able to achieve, from Kunze.

The Arrows along the bottom are where yeast is being cropped. Note 3 times in 12 days, Dashed line SG, Dark Line temperature, Pale line diacetyl.
Mark

 

[Vini2ton]

Could it be old or poorly stored extract, out of date yeast and an infection. That burnt taste is something I've only experienced in smoke-tainted wine. Chateau bushfire. Also imagine if Wolfgang Kunze and Kerry Packer had met and started a brewery, they could of called their beer... oh never mind.

 

[Brewsta]

If in fact flavour from yeast autolysis was the only reason to get beer off the yeast cake then you might be right and it would be "safe" to leave for 2-4 weeks.
But (and there is always a but) tasting like burnt car tyres isn't the only reason we should get beer off the yeast, if there was no risk at 4 weeks, I'm sure the author would have said get it off before four weeks, he isn't there is some chance of off flavours at 2 weeks.
Bit like playing Russian Roulette, at 1in6 the odds sound pretty good, add an extra bullet, 2in6, 3in6 well that's 50/50, you would have to be desperate and playing for very high stakes.

There are a bunch of other reasons, like the production of head destroying Protease A, Oxidative reactions...
Buy another fermenter and rack at the end of ferment (when you hit FG), frankly if the yeast isn't finished work in 7 days you underpitched/haven't aerated well/have a poor nutrient profile in your wort... all of which can also contribute to other off flavours.

yeah i get your point Mark, and i will definitely give it a go. could you expand on head destroying protease A & oxidative reactions?

also 7 days at 18 deg C for fermentation end? at this temp my brews are still bubbling away at 10 days, albeit a lot slower (i've never timed them) but as they are in my shed i here them bubbling every now and again when i'm in there for a while. i'll take a gravity reading at 7 days for my next brew just out of interest.
thx for you advice.

 

[Brewsta]

thx for everyone else's comments too BTW, i'm taking everything on board...
cheers.

 

[MHB]

As yeast cells age they start to Autolyse (literally self eat) flavours like burnt rubber are what we see right at the end of the process, earlier on they do some quite strange things, there are some 40 odd Protease enzymes in a yeast cell than can elute into the beer. One of the early ones is Protease A, it works in wort quite happily which is unusual, not many enzymes are too happy at low (4, give or take) pH. Protease A will just keep chipping away at the medium molecular weight proteins that are mostly responsible for head retention, ultimately reducing them to peptides.

There is a lot going on in beer even when fermentation is finished or very nearly so, over time flavour changes that lead to cardboard. well there is a well known progression of oxidisation related flavours; Berry (ribes flavour) - cardboard - bready - caramel - sherry. Not all require O2 some progress enzymically, as with most reactions the hotter the faster.

So getting the ferment finished in short order, getting the beer cool and into an O2 opaque container (HDPE containers aren't) as quickly as possible makes for better more stable beer.
Naturally if you over pitch or ferment too hot/cold there can be other problems... but that's the nature of brewing, we are always navigating a path between extremes and actions/choices often have unforeseen consequences.

Before someone starts on kitten jokes - Bubbling airlocks aren't reliable fermentation indicators - that's what hydrometers are for!
Mark

 

[damoninja]

Autolysis - the boogey man of brewing.

Most tests suggest it's really a non-issue.

Longest beer I left in primary was for 3 months. I've left heaps of beers on yeast with fruit, oak, etc for ~8 weeks at a time, Mr. Autolysis has never paid me a visit.

 

[Danscraftbeer]

I've had experiences of strange things like this in maybe 3 beer brews. Paint fumes? plastic? polystyrene? thinners? Phenols????
I never found the culprit other than stepping up my level of brewing fixed these undefined problems.

Lately I made an apple cider with M27 yeast. Pressure fermented like I usually do for beer.
For an Apple cider it took off faster than any cider I've ever made and the first gasses released smelled like this terrible fume smell. As for the odd bad beers of my past. That taint never goes away even after years of bottle conditioning.
This cider however...It got that smell early on then seems to be rid of that off smell early in the ferment.
This cider has surprizing promise actually. I don't know if this could help at all but just relating on an off flavour/smell experience.

 

[MHB]

Autolysis - the boogey man of brewing.
Most tests suggest it's really a non-issue.
Longest beer I left in primary was for 3 months. I've left heaps of beers on yeast with fruit, oak, etc for ~8 weeks at a time, Mr. Autolysis has never paid me a visit.

If by tests you mean "tastes all right to my mates" or Brulosophy, then you might be right. If on the other hand "tests" refer to the results from trained tasters, people who measure head retention, cheat by actually measuring the effects on beer with really accurate laboratory equipment then you are seriously wrong.

Or it might mean that you are really bad at some flavours, which is pretty common, my personal taste threshold for diacetyl is quite high, for Valeric Acid I'm a bit of a super smeller, enough to make me gag wouldn't even be noticed by most people. Got a friend who can smell light strike from a different postcode.

Some flavours do drop off with time, like the Banana in Wheat Beer, some times that's a good thing and part of the normal maturation process (see VDK's), sometimes its a bad thing and called staling.
Mark

 

[manticle]

Yeast autolysis is definitely not a bogey.

Given the right conditions and healthy yeast, you may not notice flavour degradation caused by byproducts of yeast breakdown but that doesn't mean it doesn't exist.

Generally I'd rather avoid it because once it's detectable, you're pretty much stuck with it.

I too have left beers on primary for a while with no discernible issues but I have also noticed discernible issues in some cases - yeast bite/vegemite being one, soapy flavours another.

Personally I'll usually rack to another vessel if the beer is going to condition longer than 5 days (so that's in addition to however long it takes to get to fg). While I might be lazy with one or another beer, 2-3 weeks condition time will absolutely get transferred and usually kept cool/cold.

Autolysis will absolutely happen - the degree and effect on your tastebuds is less absolute.
If your processes work for you, then there is no real reason to change but if, as is the case with the OP you notice an issue then all possibilities are worth examining.

 

[Brewsta]

yeah, agree…got me thinking that my tastebuds are not detecting the off flavours correctly & could very well be Autolysis from Mark's detailed explanation. I would like to think it is not oxidisation or an infection from my doing, as i am very careful with my transfers & sanitation. But still worth looking at closely in my next brew.

I also like Mark's analogy of Russian Roulette, maybe i've been lucky in the past, but not this time. I'm going to check my next brew for FG at 7 days & if done i'll keg it. The upside of this of course is freeing up my fridge for more brews!

The more i read the more i am convinced my brews before i had temperature control suffered from Autolysis, high temps & left too long on the yeast cake, they never tasted great & had that wet cardboard smell & taste.

Q.? I've never racked into a secondary before due to time constraints, other than clarification is the reason to rack once again to remove the finished beer of any additional yeast sediment that may occur in the secondary before kegging / bottling?