Issues with my beer's attenuation

[nachov]

Hi folks,

I'm having some issue with my beer's attenuation.
I used a starter following http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

My O.G. is 1.044
The primary fermentation started pretty fast (within 3 hours).
Then 2 days later, it slowed down as I would expect from a secondary fermentation; but my attenuation stopped at 1.020 and there is no way I can have it to go further.

I tried different things:
- I increased the fermentation temperature up to 66F and roused the yeast, still no working
- Then increased the fermentation temperature up to 70F and roused the yeast, there is a slight attenuation. I've reached 1.018 in one week.

Ideally, I'd like to reach F.G. 1.010 or less.

I've got my demijohn in a bucket filled with water, and there is a constant temperature kept at 70F with a fish tank thermostat.
I've checked the temperature inside the fermenter and it's around 69F.
My yeast expiry date is in 6 months. I'm using Fermentis Safale 04.

I've heard this yeast flocculates really fast;
I'm wondering if this yeast strain is able to ferment beers.
Maybe it's not able to ferment the sugar from the secondary fermentation.

It's worth mentioning that I mashed the grain at a relatively high temperature: 156F
I've heard mashing at high temperature creates longer sugar chains;
so maybe Safale 04 cannot break down those chains.

I've run out of options.
I've was thinking about adding table sugar to my brew to reach my alcohol content. I don't want to re-pitch fresh yeast, since I've played around with the temperature and it's created off-flavor. So if I wanted to use fresh yeast, I'd rather start from scratch.

Do you have any suggestion on how to get my brew to reach F.G. 1.010;
or any explanation what might have caused my brew to stop at S.G. 1.018 ?

It'd be very appreciated.
Cheers.

 

[tgmartin000]

What was your grain bill? Did you have a large percentage of specialty grains? How long was your mash? Are your thermometers calibrated?

 

[ColoHox]

Ill go out on a limb here and say you should add fresh yeast.

What I am gathering from your post, is that you might have transferred out of primary too soon. It sounds like you removed your still fermenting beer off the yeast and it stalled out at 1.020.

Of course, the other bits you describe are important too. That fermentation temp is a bit warm for US-04, although it should encourage your beer fermenting out, and might result some off flavors. That yeast is certainly able to ferment some very nice beers, though I usually use it around 60F. That higher mash temp should produce a much more fermentable beer than what you are describing, even with the presence of unfermentable sugars.

This beer is definitely salvageable, and I think more yeast would do it. It is especially easy with US-04, just rehydrate another sachet and pitch. And, before some contaminating bug gets in that can chew through what's left.

 

[WileECoyote]

+1 ColoHox,

I would also add that if your thermometer is off like both of my brand new ones are (1 is 6 deg and the other is 11 deg off), you may have of mashed at a much hotter temp than you think you mashed at, mashing real high would explain your FG numbers.

Just a thought.

Cheers

 

[CadillacAndy]

Also, how are you checking your gravity? Are you using a hydrometer or refractometer? If using a hydrometer, make sure it's calibrated using 60F distilled H2O. If using a refractometer, keep in mind that once alcohol is present, they don't work correctly without using a formula to get the correct FG. Mine almost always read 1.020 before I figured out that alcohol made them not work correctly.

 

[nachov]

Thanks for your contributions. Lots of interesting things.

About my grain bill: a large percentage of bohemian pislner light malt and Munich amber malt
in equal proportion. Those grain would give me ferment able sugars.

And the addition of specialty grain: torrefied wheat and crystal 150.
Around 10% probably. Those would give me nothing or really little fermentable sugars.

I got O.G. 1.044

My thermometers are calibrated. I stopped using my digital thermometer,
because it no longer works properly. Same issue as WillECoyote mentioned:
my digital thermometer displays weird alien digits. I used a "meat thermometer" instead.

I'm using an hydrometer. I've never thought about calibrating my hydrometer with
distilled water, it's good thinking. I'll give it a try. But I don't think that could be
that much off. And I always work out the reading with the temperature correction.

Concerning a transfer to secondary fermenter. I didn't transfer to a secondary fermenter.
I brew primary and secondary in the same fermenter. Still on the cake so.

I think I'll go with the re-pitching option.
I remember I used a yeast package which I had already used a month before (I only used half the quantity the first time).
It had been kept in the freezer, so I thought I was OK to use it again.
That could be the issue.

Should I repitch as I was doing it from scratch? Following brewer's friend calculator?
And at 60F instead of brewing at current 70F?

Thanks!

 

[ColoHox]

Concerning a transfer to secondary fermenter. I didn't transfer to a secondary fermenter.
I brew primary and secondary in the same fermenter. Still on the cake so.

I think I'll go with the re-pitching option.
I remember I used a yeast package which I had already used a month before (I only used half the quantity the first time).
It had been kept in the freezer, so I thought I was OK to use it again.
That could be the issue.

So how do you decide at what point primary is over and secondary has started? You are really doing an extended primary fermentation, there is no secondary involved here. A secondary fermentation is the transfer of fully fermented wort to a new fermenter for aging, dry-hopping, adding flavors, etc, or clearing.

Your pitch is definitely your issue. Your result is exactly what I would expect using half a pack of month-old, improperly frozen yeast, you just didn't pitch enough cells, even for dry yeast. This highlights the importance of using healthy yeast at the correct pitching rate.

At this point, my recommendation would be to re-pitch at the right concentration of cells, and maybe cool your fermenter down a bit. Use mrmalty or brewersfriend to get the cell count, although you will need at least a whole sachet of US-04. Let us know what happens.

 

[bdknuc2]

What temperature did you mash at? Depending on your mash temperature your sugars will be easier or more difficult to ferment. The lower your mash temp (148 F) you will have a more fermentable wort and the higher the mash temp (156 F) the sugars will be harder to ferment and your beer will have more body. If you mashed at a higher temperature then 1.018 may be as low as you can go.

 

[nachov]

Sorry I forgot to mention the mash temperature before.

I mashed at 156F for 60 minutes.
Actually, I might have mashed at slightly higher temperature (it's really hard to control).
But I would say 156F was my lower temperature point.
Then I did a 15 minutes mashout at 168F

I do share bdknuc2 's point of view.
I think this issue is most likely related to a too high mash temperature.

Maybe other yeast strains would be able to ferment this wort mashed at this temperature.
But I'll stick to US-04.

So, I think I'm gonna dump that beer; that brew has stayed inactive for a while. I don't want to take a risk with potential infection.

Concerning ColoHox's post:

So how do you decide at what point primary is over and secondary has started?

As I see it, the secondary fermentation is not defined by transferring the brew to a different fermenter; the secondary fermentation naturally happens when the yeast has run out of simple sugars. So, the yeast turns to the complex sugars to feed on.

I think transferring the brew to a different fermenter is advised when you want to prevent some off-flavor from yeast autolysis. Specially when you're brewing a lager (due to long time conditioning). But some people say that nowadays with most laboratory-manufactured yeasts, it's no longer required since very little autolysis is produced. But it's highly debatable

In my situation, I believe the yeast cannot feed on those complex sugar. They might be too complex

I've used brewer's friend pitch rate calculator to work out my starter size and pitch rate.
Actually, I pitched at 0.75 (million cells / ml / degree plato).
I could have pitched at 1; but I believe 0.75 would give me the flavor profile I'm looking for. I don't think I messed up with my pitch rate so.

I think most likely with a high mash temperature, I've created long chains of sugar which cannot be broken down by this good pal US-04.

I used specialty grains, so I wanted a good thick body beer. That's why I mashed at high temp. Do you have any suggestions concerning the best mash temperature to achieve a good body and still be able to get the yeast to ferment the complex sugar out?

That'd be very appreciated.
The amazing thing about homebrewing is that you learn every day;
and eventually you get one step closer to create an awesome beer.

 

[ColoHox]

Concerning ColoHox's post:
As I see it, the secondary fermentation is not defined by transferring the brew to a different fermenter; the secondary fermentation naturally happens when the yeast has run out of simple sugars. So, the yeast turns to the complex sugars to feed on.

I think transferring the brew to a different fermenter is advised when you want to prevent some off-flavor from yeast autolysis. Specially when you're brewing a lager (due to long time conditioning). But some people say that nowadays with most laboratory-manufactured yeasts, it's no longer required since very little autolysis is produced. But it's highly debatable

If you are going to have your own definitions for common practices, it will really complicate the conversations here. It is indeed true that your yeast will metabolize the sugars sequentially, but delineating the transition from glucose utilization to maltose utilization serves no practical purpose. Measuring this outside of a lab results in arbitrary units. And, yes, lets not get into autolysis

I've used brewer's friend pitch rate calculator to work out my starter size and pitch rate.
Actually, I pitched at 0.75 (million cells / ml / degree plato).
I could have pitched at 1; but I believe 0.75 would give me the flavor profile I'm looking for. I don't think I messed up with my pitch rate so.

I think most likely with a high mash temperature, I've created long chains of sugar which cannot be broken down by this good pal US-04.

When I put your numbers into the BF calculator (assuming you made a 5gal batch, which you haven't mentioned), at the pitching rate you describe, you need nearly 2 whole packets of US-04, not half of a month old packet, or a starter. The amount you pitched would be fine for a 1 gallon batch, assuming it was properly stored and healthy.

I used specialty grains, so I wanted a good thick body beer. That's why I mashed at high temp. Do you have any suggestions concerning the best mash temperature to achieve a good body and still be able to get the yeast to ferment the complex sugar out?

If 156F is the low end of what you think you mashed at, then I would agree that there is likely a large proportion of unfermentable sugars in your wort. You only got 48% actual attenuation. When I mash for high body (156-158F), I routinely get >60% actual attenuation, even with crystal malts. The use of crystal or other similar specialty malts at 15% of your grain bill will only reduce your fermentability by 1-4% (depending on the C). That said, maybe your issue with this beer is a trifecta of mash temp, grain bill, and underpitching.

Brewers have to find a balance between adding specialty malt that contributes body and a mash temperature that provides fermentability. Very generally, as equipment and recipes can be so different, you can mash lower if you add malts that contribute body. I would probably mash at 152F if I was using high body malts like the crystals, caras, biscuits, just to balance things out.

Sorry you have decided to dump a fixable beer.

 

[bdknuc2]

You can also try mashing for 90 minutes your OG may not change much but this give the enzymes some more time to work on the sugars and make them easier to ferment, leading to a higher attenuation.

 

[nachov]

From all the comments I've gathered here, I think I mashed at too high temperature (156F or probably higher).

If 156F is the low end of what you think you mashed at,
then I would agree that there is likely a large proportion of unfermentable sugars in your wort.
You only got 48% actual attenuation.

Indeed, I got an attenuation around 50%.

I'm a newbie and I had never had too much interest in the mash temp.
Now I got it's paramount importance.
I'm doing some experimental batches, small sizes (1 gallon)
That explains why I used very little yeast.

I'd like to make the most of my specialty grains; and get a thick mouthfeel body from those grains.
I'm using bohemian pilsner malt and munich amber malt.
I'd like to mash my malts separately at 152F (to get a bit of thickness from my munich amber malt)
and mash my specialty grains in a cereal mash.

Is that worth the hassle?
Or should I just mash my specialty grains with the whole bulk of malt at 152F for 90 min?

 

[WileECoyote]

I think you might be a little confused with some of what you have replied with,

You get thicker mouthfeel and body from several things, including mashing at higher temps not lower, your grain bill will make the biggest difference in mouthfeel, water to grain ratio also, but it is several factors working together to have your beers come out the way you want.

And why are you going to dump your beer? it fermented already and the chance of infection is minimal, it will be thick if it truly has reached FG at 1.020, If you are doing test batches you need to let them all finish out and taste every one to see how what you did affects the beers.

Mashing for 90 min instead of 60 min will not fix a grain bill that dosnt have mouthfeel built into it, and their isn't going to be a huge gain ether.

You are getting real good advice from experienced brewers here, I might be wrong but it seems like you are kinda quick to discount a lot of the replies.

Any way good luck and I truly hope you figure it out.

Cheers

 

[nachov]

I dumped my beer because it smelled weird, kind of rancid. I played around with the temperature and it's spent 3 weeks inactive. I take into account all the replies, but it seems different persons are shooting in different directions.

I found this damn good video about mash temps:

It explains what you've just said about a higher mash temp for a thicker mouthfeel.
I try to figure out more about the protein rest as well.

I'd just like to mention that I've come across lot of arrogant people on this forum (I don't specially mention this post). The ones who are happy to help are welcome, for the rest I don't want to hear from them. I'm not a chick and I don't want to make a drama out of that

I'm a newbie, I try to gather the pieces to get a better understanding of the different processes of brewing.

 

[Bogforce]

How did you pitch the yeast? Did you rehydrate it?

 

[WileECoyote]

I agree with you 100%, when you are new to brewing, its really hard to figure out what is right when you have 3 or 4 people all saying different things, especially when they are replying with opposite answers, that drove me nuts when I started out and still dose lol

Keep looking everything up the way you are and keep asking here, their really are a lot of great brewers here ready to help you become a great brewer.

a lot of brewing is preference too, so that dosnt help a lot of times.

And I know this might sound like BS but its true, some beers in the fermenter will smell like rhino ass, and when finished it will change into a wonderful smelling/tasting beer, so don't let that fool you into dumping a beer, only you can decide if it really rancid.

try a search on mouthfeel and that should help give you more answers too.

Cheers

 

[WileECoyote]

Something else that might help, is try using proven recipes that in the description say lots of mouth feel, or at least look up recipes like that to see what they have in common.

Carapils, wheat, oats, ext, all contribute to mouthfeel along with mash temps and water volume to grain ratio and age of beer helps too, young beer can have less mouthfeel too.

They all work together, keep reading and asking, it will come together.

Cheers

 

[nachov]

Good idea!
I'll go through different thick mouthfeel recipes.

 

[nachov]

Hi,

I did a new batch and I'm experiencing the same issue.
My O.G. was 1.052 and the fermentation seems to have stopped at SG 1.026
after 1 week at 64F.

Does it seem normal? Should it take longer than 1 week to reach around 1.010 - 1.015?

I mashed the grain at 150F for 60 minutes.
I didn't do a mashout. I sparged the grain with water at 160F, recirculate the grain and rest it for 10min.
I got a decent efficiency at 76%.
Then boiled for 60min.
I was very careful with the pitch rate and the atemperation steps.
The wort temperature and yeast temperature was the same.
The fermentation started within 6 hours and was very vigorous.

I don't really know what went wrong.
I thought with mashing at 150F and sparging at 160F I would get a decent amount of fermentable sugar.
I went through:
- the pitch rate
- mashing temp
- sparging temp
- fermentation temp
- pitch temperature
- efficiency, O.G.

Maybe I should check the calibration of my thermometer and my hydrometer.

I've run out of options, do you have any suggestions?
Cheers!

 

[nachov]

I've checked my hydrometer's calibration with water from my well (shows SG 1.000)

 

[40watt]

I know you said you made a starter, which I never do with dry yeast, but did you say you store it in the freezer?

 

[40watt]

I always get great attenuation. Single digits if I want it. I'm sure we can find a solution for you.

 

[nachov]

I store my dry yeast packs in the freezer around -2F (-19C I believe so).
I don't store the starter in the freezer, I use it straight away when it's fermented out after a couple of days.

 

[40watt]

Aside from yeast health, I'd like to make sure you are getting good conversion in your mash.

First I'm concerned about yeast health. Don't keep it in the freezer.
I want details on your starter.
For me the dry yeast actually does better just being rehydrated. DME is actually not good for dry yeast. Neither is RO or distilled water. You want something with a little mineral content.

 

[40watt]

Even dry yeast can be damaged at those temps. It may wake up in a starter, but that doesn't mean they are healthy enough to ferment a beer.

Fridge only. Trust me.

 

[40watt]

I ran across some info saying you CAN freeze it, but it must still be vacuum packed.

 

[ejluttmann]

I'm fairly new to brewing and my brown ales and porters both have had a OG in the 1.058-1.060 range but after two weeks got stuck in the 1.018-1.020 range - I just cold crashed for a week and kegged them ... I read somewhere that lack of proper aeration of the wort prior to adding the yeast could also result stuck fermentation. I'm going to try adding pure oxygen next time to see if that helps.

Also, those last beers that only got down to 1.020 were still great beers, so don't dump it


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[40watt]

Oxygen is definitely a big part of setting yourself up for success.

Yeast health is number one of course.

 

[ejluttmann]

Yep, in my case I'm sure my yeast is good ... I use a starter using liquid yeast 24 hours prior to pitching ... which is why I'm now looking at adding oxygen. Been trying to just adjust one thing at a time, too many variables and it's hard to determine what worked and what didn't. It's all just learning what works best for you


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[nachov]

I don't have an oxygen kit,
I just rely on the old shaking technique.
I shook the hell out of it for 3 minutes.

I'm aware that might not be enough.
And the fact that I keep my yeast in the freezer didn't help either.

Is there a way to save the few yeast packs which have been kept in the freezer?
Or it's best to buy new packs. It's not very expensive anyway.

Also, those last beers that only got down to 1.020 were still great beers, so don't dump it

Is there a way I could reach a higher abv? It's probably 3.5% right now.
I'm sure that's gonna taste good, but that will definitely lack of alcohol.
Is it worth pitching a new yeast crop?

Thanks!

 

[40watt]

Any unopened yeast packs should still be viable.

You can get by with shaking if you aren't doing big beers. You just have to have healthy yeast.
Dry yeast don't have a working cell membrane until they are rehydrated. So consider how you treat them.

If you just have to have more alcohol, I think I would lean more towards repitching healthy yeast than adding sugar.

You are pitching into a hostile environment. So pitch plenty and pitch healthy. Rather than making a starter, I would just rehydrate in sterile water of 90-100 degrees. Use spring water or tap water if it's free of chlorine. RO water will cause nutrients and minerals to pass from the yeast into the water while the cell membrane is all dried up.

Also, dried yeast works fine, but I would start to consider the benefits of liquid. I just get better results.

 

[ejluttmann]

I've never re-pitched but then 4-5% is fine with me ... I'm just looking to get a good drinking beer, typically something better than I can get locally on tap - I'm not a IPA lover and that seems to be the fad now a days. Also, I love the process of brewing almost as much as the product of brewing


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[nachov]

I didn't make a starter for that current batch.
But I did rehydrate the yeast with tap water (which I had boiled the day before and have it rest overnight).

I pitched the dry yeast in a glass of water at 86F, following the dehydration instructions of the manufacturer (Fermentis).
I left it undisturbed for 15 minutes;
then I gave it a swirl every 5 minutes during 30 minutes;
then I poured a bit of wort into the glass.

I was very careful with trying to maintain a slow steady loss of temperature during dehydration.
During the entire process I had a loss of 2F every 5 minutes (that sounds like a good atemperation).
And eventually I pitched when I reached the same temperature as my wort (64F).
The total process took 55min

Concerning the mash temperature, I was very careful no to mash at high temp. So I mashed at 150F for 60 minutes.
Sparged with water at 160F for 10 minutes.

Maybe the low oxygen level is the reason why I didn't hit a good attenuation.
Although, I brewed a cider batch a couple of months ago with the same oxygenation technique (shaking like crazy for 3 minutes).
With O.G. 1.083
I reckon it took a hell of time to ferment: 5-6weeks
But I reached F.G. 1.000

Could be my yeast viability after having spent a while in the freezer.
BTW, the expiry date is still OK: September 2014.

It's kind of weird. The starter I made for the previous batch stopped at F.G 1.020 (with O.G. 1.043)
The batch itself stopped at 1.020 as well.
My new batch(current batch) stopped at F.G 1.026 (with O.G. 1.052).
That poor attenuation is actually consistent.

I'm gonna try with adding fresh yeast.
If it works that would confirm the yeast viability theory.

Cheers.

 

[nachov]

Hi,

I've added some DME to my brew, just enough to get the extra alcohol content I was looking for. I boiled the DME for 15minutes; and cooled it down to brew temperature; and added it to the brew. The fermentation restarted within 1 hour.

So I guess my yeast was still in pretty good shape.
I've read something about "the Maillard reaction".

For that brew I did boil a small quantity of wort (around half a gallon).
And actually I didn't swirl during the boil.
So, maybe at the bottom of the pot some melanoidins formed; and that might have led to produce more unfermented sugars.

I've heard that if you boiled a 5 gallon batch for 2 hours, you might produce more of those melanoidins; and eventually you would lose 1.005 SG to unfermentable sugar, which is not too much but still something.

If the loss if such for a 5 gallon batch, I don't know what would be the loss for 1hour boil of a 1/2 gallon batch (in a pot filled half way).

Do you think that could explain my low attenuation?

Cheers.

 

[40watt]

It definitely could.
That is a very small concentrated boil. A technique sometimes used to caramelized and sweeten the final product in a Scotch Ale.

Extract itself is less fermentable than an all grain wort in many cases.
Couple that with the Miallard reactions you WILL get from such a concentrated boil, and you have a far less fermentable wort.

 

[nachov]

My FG was 1.026
I raised the SG to 1.038 with DME.
Let's see what I get. I'd be happy even with FG 1.030

Extract itself is less fermentable than an all grain wort in many cases.

I've heard of that before.
I don't know if it's a myth but experienced brewers have seen lower attenuation with extracts. There might be a reason.

 

[40watt]

It is a fact.
Extract is made in a "middle of the road" fashion. It needs to be useful for the widest variety of beers possible.
Mashing your own grain allows you to produce a wort as fermentable as YOU want it.
Also the process of producing and concentrating the wort into extract makes it less fermentable. An extract beer will be slightly darker than the all grain equivalent.

Choosing the lightest extract possible helps. Get any color or character from steeping grains.

 

[40watt]

I don't think I would ever do a very small batch with extract.
Brew in a bag would be so easy at that point.

 

[40watt]

Dbl

 

[40watt]

If you used a very light DME, I could see you reaching 1.028.