Estery lager

[@RoyalGallon]

I’ve tried 3 times now to brew a really clean crisp American lager, but I’m really struggling with a fruity ester flavour instead of a clean nothingness from the yeast I want.

The obvious culprit is fermentation temperature however I’m happy that I have this controlled. I’ve been holding at 11C through the ferment in a glycol chilled Grainfather conical.

The second obvious culprit could be pitch rate. Here I’ve pitched a 34/70 starter of 3L into a 21L brew. This I’m less confident about.

What other areas would people recommend controlling or looking at to get rid of the esters?

 

[JohnSand]

I think you're on the right path. I also had trouble with 34/70, and never got it right. I switched to Bootleg Arlington, and like it better.

 

[McMullan]

Lager yeast have 'cleaner' profiles than ale yeast generally, but they still have identifiable profiles. You won't get 'clean nothingness'. I haven't tried 34/70, so can't comment on it. I doubt you're under pitching, but are you oxygenating the wort? I'd also recommend having a go at repitching freshly harvested yeast into a fresh batch of wort.

 

[Steveruch]

What's the recipe?

 

[@RoyalGallon]

I think you're on the right path. I also had trouble with 34/70, and never got it right. I switched to Bootleg Arlington, and like it better.

That’s a good thought - I did start using S-189 yeast and swapping to 34/70 has improved from there - it could be just finding the right yeast for me.

Lager yeast have 'cleaner' profiles than ale yeast generally, but they still have identifiable profiles. You won't get 'clean nothingness'. I haven't tried 34/70, so can't comment on it. I doubt you're under pitching, but are you oxygenating the wort? I'd also recommend having a go at repitching freshly harvested yeast into a fresh batch of wort.

Oxygenation as well - another great point. I transfer to a 5L jug then into the FV maybe a little more vigour there.

 

[@RoyalGallon]

What's the recipe?

It’s based in Bud - I once worked in the brewery in the UK so remember the recipe more or less and remember the specs as I was in the lab.
Pasted below.

 

[jdauria]

From everything I have seen, it's recommended to not make starters with dry yeast. Better off just pitching a few packs of 34/70 instead. Whether that's why there are esters, not sure, but it's one thought. Did you ferment in 50's or do a warm ferment lager and ferment in 60's? 34/70 is a fairly clean yeast, but at warmer temps it can release some floral and fruity esters.

 

[@RoyalGallon]

From everything I have seen, it's recommended to not make starters with dry yeast. Better off just pitching a few packs of 34/70 instead. Whether that's why there are esters, not sure, but it's one thought. Did you ferment in 50's or do a warm ferment lager and ferment in 60's? 34/70 is a fairly clean yeast, but at warmer temps it can release some floral and fruity esters.

Maybe that’s it - I made a starter from a single pack of dry yeast and pitched that.

Fermentation was 11C (52F) for almost 2 weeks then slowly ramped up to 15C (59F) 1C over another 10 days.

My thought that would be cool enough.

 

[Miraculix]

You're probably fermenting too cold. At room temperature, I had a pretty clean ferment with 3470, cleaner than any ale yeast I know. Pretty close to your mentioned nothingness. I bet that around 15-16c this yeast would be even cleaner. Maybe it gets fruity once you go lower? Happens with other yeasts too so I wouldn't be too surprised if this happens with 3470 as well.

 

[jdauria]

Maybe that’s it - I made a starter from a single pack of dry yeast and pitched that.

Fermentation was 11C (52F) for almost 2 weeks then slowly ramped up to 15C (59F) 1C over another 10 days.

My thought that would be cool enough.

Yep that's cool enough.

 

[@RoyalGallon]

You're probably fermenting too cold. At room temperature, I had a pretty clean ferment with 3470, cleaner than any ale yeast I know. Pretty close to your mentioned nothingness. I bet that around 15-16c this yeast would be even cleaner. Maybe it gets fruity once you go lower? Happens with other yeasts too so I wouldn't be too surprised if this happens with 3470 as well.

That’s an interesting idea - my gut feel was always cooler = cleaner. Could be stressing the yeast a little.

This is probably something to try.

I know I’ll try all these things at once and never know which one it was

 

[Miraculix]

That’s an interesting idea - my gut feel was always cooler = cleaner. Could be stressing the yeast a little.

This is probably something to try.

I know I’ll try all these things at once and never know which one it was

Sounds like my usual approach as well

 

[mashpaddled]

Definitely getting yeast stress somewhere along the way. I don't think fermenting too cool is the culprit though. I also don't think it's an issue of strain because that strain is used worldwide to make very clean lagers. I suspect the overall fermentation approach is less than ideal for the style but the recipe itself is part of the issue. Rice converts almost entirely to glucose so your recipe is a lot like brewing a recipe that is 80% pils/20% sugar. Yeast struggle with a large volume of glucose at the outset of fermentation generally. If your fermentation process is flawed, then that creates extra opportunities for off flavors. In Belgian beers adding all that sugar promotes ester production and you want that in those beers. Here you don't.

The best thing to do would be to try changing one factor in the recipe/process at a time but I think you need to pitch dry yeast without a starter, oxygenate well and add nutrients. Keep in mind that recipe leaves nowhere to hide flaws so your fermentation process as to be as close to perfect as possible.

 

[Miraculix]

Definitely getting yeast stress somewhere along the way. I don't think fermenting too cool is the culprit though. I also don't think it's an issue of strain because that strain is used worldwide to make very clean lagers. I suspect the overall fermentation approach is less than ideal for the style but the recipe itself is part of the issue. Rice converts almost entirely to glucose so your recipe is a lot like brewing a recipe that is 80% pils/20% sugar. Yeast struggle with a large volume of glucose at the outset of fermentation generally. If your fermentation process is flawed, then that creates extra opportunities for off flavors. In Belgian beers adding all that sugar promotes ester production and you want that in those beers. Here you don't.

The best thing to do would be to try changing one factor in the recipe/process at a time but I think you need to pitch dry yeast without a starter, oxygenate well and add nutrients. Keep in mind that recipe leaves nowhere to hide flaws so your fermentation process as to be as close to perfect as possible.

I kind of agree with the reasoning, only one thing, yeast does not struggle with big portions of glucose. Glucose is literally the easiest sugar to metabolize for the yeast, so the yeast is pretty happy about increased doses of glucose. However, and here is the key point at which you are probably right, glucose is also known to boost ester expression of the yeast so this could definitely play a role in the experienced fruitiness. Still, It might only be a part of the reason because I know that there are a lot of American adjunct lagers and similar out there which are being probably brewed with 3470 and loads of similar adjuncts and they are actually pretty clean.

 

[mashpaddled]

I kind of agree with the reasoning, only one thing, yeast does not struggle with big portions of glucose. Glucose is literally the easiest sugar to metabolize for the yeast, so the yeast is pretty happy about increased doses of glucose. However, and here is the key point at which you are probably right, glucose is also known to boost ester expression of the yeast so this could definitely play a role in the experienced fruitiness. Still, It might only be a part of the reason because I know that there are a lot of American adjunct lagers and similar out there which are being probably brewed with 3470 and loads of similar adjuncts and they are actually pretty clean.

Generally yes glucose is easily fermented; however, research indicates when there is a large percentage of glucose at pitching this tends to lead to fermentation problems--or what we consider problems--particularly with stuck fermentation. This is how pitching champagne yeast became the partially incorrect repeated cure for a stuck fermentation. Wine/champagne yeast will consume a lot of that glucose and kick off the beer yeast to do its thing if pitched early in a stuck fermentation. Wine/champagne yeast won't do anything if the beer strain stalled out due to lack of nutrients, ABV threshold, etc. later in fermentation. This is also why if you are adding a large amount of simple sugar to a beer in which you don't want ester production you are best off adding it later in fermentation.

 

[monkeymath]

If you're looking for "clean nothingness", then I'd suggest sticking with a neutral ale yeast, like a chico or kölsch strain. Imho well made lagers have a pretty strong and immediately recognisable fermentation profile - although not the esters you describe.

I once made a Helles with Imperial L17 Harvest which had a noticeable red apple ester once the bottles were fully conditioned (it was absent at bottling). From what I gathered afterwards, I fermented it too cold (at 8 Celsius) for the strain and most likely some oxidative damage happened as well.

So, yeah, if you're just looking for "clean nothingness", then I'd just go the easy route and use chico.

 

[@RoyalGallon]

Definitely getting yeast stress somewhere along the way. I don't think fermenting too cool is the culprit though. I also don't think it's an issue of strain because that strain is used worldwide to make very clean lagers. I suspect the overall fermentation approach is less than ideal for the style but the recipe itself is part of the issue. Rice converts almost entirely to glucose so your recipe is a lot like brewing a recipe that is 80% pils/20% sugar. Yeast struggle with a large volume of glucose at the outset of fermentation generally. If your fermentation process is flawed, then that creates extra opportunities for off flavors. In Belgian beers adding all that sugar promotes ester production and you want that in those beers. Here you don't.

The best thing to do would be to try changing one factor in the recipe/process at a time but I think you need to pitch dry yeast without a starter, oxygenate well and add nutrients. Keep in mind that recipe leaves nowhere to hide flaws so your fermentation process as to be as close to perfect as possible.

Interesting thoughts - thanks.

I have already dialled back the rice from 30 to 20%. The former being what was used in the brewery. However I do wonder about yeast nutrition. Is there just not enough in the wort to sustain the health of the yeast - or as @Miraculix says is the sugar rich wort a driver for water production?

Both probably something to investigate.

 

[marc1]

It could be that you might just prefer a different lager yeast for this kind of beer. Try a few others and see what you get.

 

[Miraculix]

Generally yes glucose is easily fermented; however, research indicates when there is a large percentage of glucose at pitching this tends to lead to fermentation problems--or what we consider problems--particularly with stuck fermentation. This is how pitching champagne yeast became the partially incorrect repeated cure for a stuck fermentation. Wine/champagne yeast will consume a lot of that glucose and kick off the beer yeast to do its thing if pitched early in a stuck fermentation. Wine/champagne yeast won't do anything if the beer strain stalled out due to lack of nutrients, ABV threshold, etc. later in fermentation. This is also why if you are adding a large amount of simple sugar to a beer in which you don't want ester production you are best off adding it later in fermentation.

My guess is, that an abundance of glucose at the beginning makes the yeast "taking less care" of the other pathways. The yeast is like "yeaaaahhh glucose, gimme all of that junk food stuff, so yummy!" while underdeveloping all the other enzymes and whatnots that are part of the metabolic pathways the longer sugars get metabolized through. I have seen graphs where it was clearly visible that the yeast first only metabolized the available glucose, then halted a short time, fermented the available fructose and then contiued with the longer ones. Maybe some yeasts might "unlearn" to metabolize the longer sugars when getting the short one (glucose) in abundance first.

But that is actually more of a stalling issue, which is not the case here.

Also, why should rice result in glucose only? It is starch, isn't it? Shouldn't it get attacked by the mash enzymes just the way the barley malt starch gets attacked and chopped into pieces? Meaning, leaving shorter and longer pieces behind, according to mash temp etc.?

The good thing about rice is, it is not plain sugar, so there are some proteins and other things inside, so there are sources of nutrients within the rice. Probably not as much as in barley malt, but definitely not as bad as pure sugar.

 

[McMullan]

I'm not sure about these claims too much glucose is bad for yeast. Some reference to the research/data would be appreciated. Glucose is pretty much the primary simple sugar metabolised by pretty much every living thing in the biosphere. The most common carb in malted barley wort is maltose and it gets hydrolyzed to glucose inside yeast cells. I routinely brew Mild ales, partly to help culture up yeast, which sometimes include up to 30% inverted (simple) sugars - glucose and fructose, which is essentially 'glucose' here - without noting any ill effects in terms of yeast vitality. Quite the opposite actually, but I do have all factors covered. Nor do I recognise this idea glucose promotes elevated ester production. The lusciousness added by English inverted brewing sugars is a very subtle character. Subtle enough that the serious beer drinker needs to train himself or herself to appreciate it. Point being the claimed higher ester production promoted by higher glucose levels is insufficient to mask subtle elements of beer. For some reason, professional brewers are well aware that dry yeast has to be repitched before it starts to perform optimally and ferment out quality beers consistently.

 

[Pablo 54]

I’m with jdauria on the “don’t make a starter with 34/70”. Either sprinkle it on top of the wort or put it in the bottom and fill on top of it. I used to hydrate as well until I came across David Heath’s video on yeast - Beer Yeast Research News May 2018. I have not touched dry yeast since other than to sprinkle it in the fermenter.

 

[Dland]

Since it is a lager, how long did you lager it? Cold crashed after full fermentation and carbing and conditioning for for a month or three is sort of a minimum to achieve "lager". More time is better.

This is not to say that a beer made with lager recipe has to condition that long to be good. Some of my lagers taste pretty darn good a few weeks past cold crash, but if on wants the clean, crisp and clear, one has to have some patience.

 

[Beermeister32]

Since it is a lager, how long did you lager it? Cold crashed after full fermentation and carbing and conditioning for for a month or three is sort of a minimum to achieve "lager". More time is better.

Agree. Let it age out for 90 days.

 

[@RoyalGallon]

Agree. Let it age out for 90 days.

Yeah it’s been at 4C for around 3 months now. So it’s beautifully bright and in terms of crispness it’s there - just the lingering fruity ester flavour that I don’t think will condition out.

I tried some last night and it tastes sweet - I think this is either being emphasised by the eaters or it is sweet and this is bringing out the fruity flavours.

Either way they’re not the sort of attributes that I think lagering will change much.

 

[Beermeister32]

W34/70 is pretty reliable. I usually pitch at 48F and hold it at 50F. Not sure where those esters may have come from.

Once in a while you get a batch where the beer Gods are looking disfavorably upon you.

Lighter lagers have a clean light finish, it is easy to detect flaws. Brewers of old would blend 10 batches or more into their wooden kegs to produce even flavors. I’d blend it back in the glass with something else on tap until the keg kicks.

 

[McMullan]

I used to hydrate as well until I came across David Heath’s video on yeast - Beer Yeast Research News May 2018.

This one?



So let me get this straight. A self-proclaimed master dry yeast salesman brewer, apparently with over 30 years experience producing warts, didn't realise there were no biochemical reasons to oxygenate wort when pitching dry yeast? He was 'taken aback' when he heard this a few years ago, was he? I see. I wonder if our master saleman realises how important it is to 'aeriate' warts when pitching wet yeast, including repitched dry yeast? He must have confused the Jesus out of his disciples And he imagines a fluffed-up internal technical report presented as part of a marketing campaign by a major yeast company he can't remember the name of represents credible research using the latest technology, does he? I see. What Fermentis actually claim - they've published no scientific data - is they found no significant difference between hydrating their active dry yeast and sprinkling directly onto wort, in the wort conditions used in their experiments. In fact, if you've been rehydrating dry yeast before pitching, Fermentis recommends you carry on hydrating them. And I'm pretty sure Fermentis would recommend rehydration under some conditions, e.g., when innoculating yeast in high gravity worts.

My own observations show dry yeast perform much better and ferment better beers when repitched fresh from harvesting. Claims active dry yeast are the freshest yeast available to brewers is utter porky pies.

Try repitching freshly harvested yeast, @@RoyalGallon. You might find it's chalk and cheese compared with beer from the first fermentation.

 

[Pablo 54]

So, can I take this as it doesn't matter either way?

 

[Miraculix]

...is utter porky pies.

Man, you gotta love the English language for expressions like this one.

I just recently posted a gif on MS Teams to a colleague at work, which was a monkey orbited by flying pies with a big sign underneath "don't tell me porky pies".

Needles to say, she did not get it.

"Was sind "porky pies"?"




Found it!

 

[z-bob]

Interesting discussion about too much glucose at the beginning of fermentation. No idea if that's the problem, but how about this? Leave out the rice; shoot for a little lower OG, then when the fermentation slows down add about 5% table sugar? I have made cream ales using 95% pale malt and 5% sugar and it works very well.

 

[Miraculix]

Or just leave out the sugar? Rice broke in a certain flavour, not only abv. Sugar is just good for abv ... Personally for me not desirable, but that surely might differ from person to person.