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General Category => General Homebrew Discussion => Topic started by: tcanova on February 26, 2014, 03:53:14 PM

Title: Quick question about attenuation
Post by: tcanova on February 26, 2014, 03:53:14 PM
I am wanting to make a session beer, nothing fancy, just some base grains, 2 row, munich maybe a little crystal and some carapils, and I am thinking of mashing in the 154-156 range.  What is the best way to figure how this will effect the attenuation?  I am just planning on using Safale-05 yeast.  Thank you.
Title: Re: Quick question about attenuation
Post by: Iliff Ave Brewhouse on February 26, 2014, 04:11:29 PM
I am wanting to make a session beer, nothing fancy, just some base grains, 2 row, munich maybe a little crystal and some carapils, and I am thinking of mashing in the 154-156 range.  What is the best way to figure how this will effect the attenuation?  I am just planning on using Safale-05 yeast.  Thank you.

I recently did a session beer. My attenuation was drastically lower than usual due to mashing at 158 and conducting a mash out which I never do. From what I understand, the mash out halts enzyme activity which affects attenuation. I got 67% attenuation with S04 compared to normal values between 75-80%.
Title: Re: Quick question about attenuation
Post by: denny on February 26, 2014, 04:25:32 PM
I am wanting to make a session beer, nothing fancy, just some base grains, 2 row, munich maybe a little crystal and some carapils, and I am thinking of mashing in the 154-156 range.  What is the best way to figure how this will effect the attenuation?  I am just planning on using Safale-05 yeast.  Thank you.

Take look through the NHC archives for a 2012 presentation by Greg Doss of Wyeast.  It was about the effects of mash temp using various strains of yeast.  But keep in mind that your recipe will likely have a lot more effect than mash temp will.
Title: Re: Quick question about attenuation
Post by: garc_mall on February 26, 2014, 04:28:42 PM
In my opinion, even with all of the information out there, you are looking at somewhere like a 10% range. It's a bit of a crapshoot.

If you really want a session beer (3-4%), I recommend mashing quite a bit higher (158-162) so you can get the body that you expect in a beer. I find session beers that are mashed lower to end up very thin.
Title: Re: Quick question about attenuation
Post by: HoosierBrew on February 26, 2014, 04:46:05 PM


If you really want a session beer (3-4%), I recommend mashing quite a bit higher (158-162) so you can get the body that you expect in a beer. I find session beers that are mashed lower to end up very thin.

+1.  Much below that range and it gets overly thin IMO.
Title: Re: Quick question about attenuation
Post by: morticaixavier on February 26, 2014, 04:52:53 PM
Yeah, I haven't noticed a huge difference in attenuation based on mash temp except that ~148-150 produces a pretty fermentable wort, ~150-156 produces a slightly less fermentable wort (< 5%?), and ~157-162 produces a good amount of remaining body for session. given this I just go with 148 for beers I want to dry out, 162 for beers i DON'T want to dry out and 155-157 for beers that I want somewhere inbetween. not very scientific
Title: Re: Quick question about attenuation
Post by: denny on February 26, 2014, 05:29:53 PM
FWIW, Greg Doss found the greatest fermentability at 154F IIRC.
Title: Re: Quick question about attenuation
Post by: ccfoo242 on February 26, 2014, 05:34:27 PM
Definitely go for the 160f range. But one thing I found is if you use beer smith it gets funky when you go above 158 if I recall correctly. Brad said this has to do with published formulas. So I set mine to 158 to get an idea where it should finish but use 160 to get the proper water temp to add.


Sent from the future using Tapatalk
Title: Re: Quick question about attenuation
Post by: hopfenundmalz on February 26, 2014, 05:39:11 PM
FWIW, Greg Doss found the greatest fermentability at 154F IIRC.
It was 153F for Pils malt. There was a local maximum. Fairly flat at lower temps until 148 or 149, then it increases with the peak at 153, then decreases with a steady slope as the temp increases.

The yeast used will have a big influence, one should consider that also. Greg had data for yeast strains also.
Title: Re: Quick question about attenuation
Post by: garc_mall on February 26, 2014, 06:00:06 PM

The yeast used will have a big influence, one should consider that also. Greg had data for yeast strains also.

WY1968 is my favorite for Session beers. It tends to be a little less attenuative, and it drops out and clears quickly. I like to drink my session beers as fresh as possible.
Title: Re: Quick question about attenuation
Post by: erockrph on February 26, 2014, 06:56:19 PM
FWIW, Greg Doss found the greatest fermentability at 154F IIRC.
It was 153F for Pils malt. There was a local maximum. Fairly flat at lower temps until 148 or 149, then it increases with the peak at 153, then decreases with a steady slope as the temp increases.

The yeast used will have a big influence, one should consider that also. Greg had data for yeast strains also.

I also believe he conducted his mash for 45 minutes regardless of temperature. I always suspected that you may see the fermentability of the lower-temp mashes in this study increase if they were given more time.

Still, Greg's talk did make a difference in my practice. I don't bother mashing below 153F any more, I mash at 156F for a little more body and 162 for session beers.
Title: Re: Quick question about attenuation
Post by: hopfenundmalz on February 26, 2014, 07:01:38 PM
FWIW, Greg Doss found the greatest fermentability at 154F IIRC.
It was 153F for Pils malt. There was a local maximum. Fairly flat at lower temps until 148 or 149, then it increases with the peak at 153, then decreases with a steady slope as the temp increases.

The yeast used will have a big influence, one should consider that also. Greg had data for yeast strains also.

I also believe he conducted his mash for 45 minutes regardless of temperature. I always suspected that you may see the fermentability of the lower-temp mashes in this study increase if they were given more time.

Still, Greg's talk did make a difference in my practice. I don't bother mashing below 153F any more, I mash at 156F for a little more body and 162 for session beers.

Kai had similar results. I don't remember how long he mashed, but it is on his page.
Title: Re: Quick question about attenuation
Post by: beersk on February 26, 2014, 08:51:22 PM
So, if mash temperature below 153F and if pure o2 and plentiful yeast is pitched, what would cause under or over attenuation? Recipe? What if the recipe is a pilsner? Or a simple IPA? Could too much pure o2 cause problems?
Title: Re: Quick question about attenuation
Post by: morticaixavier on February 26, 2014, 08:56:01 PM
So, if mash temperature below 153F and if pure o2 and plentiful yeast is pitched, what would cause under or over attenuation? Recipe? What if the recipe is a pilsner? Or a simple IPA? Could too much pure o2 cause problems?

kind of a broad question. with a low mash temp I would expect pretty high attentuation (assuming a simple base malt recipe with not too much unfermentables added). As I understand it, too much o2 shouldn't cause an increase in attenuation.

under attenuation in that case would tell me that the yeast pooped out, either too high a pitch temp so they went nuts and dropped out early, too low a ferm temp so they were stunned and... dropped out early. too little/too much yeast so they got pooped out/over excited and ... dropped out early.
Title: Re: Quick question about attenuation
Post by: Joe Sr. on February 26, 2014, 10:05:19 PM
So, if mash temperature below 153F and if pure o2 and plentiful yeast is pitched, what would cause under or over attenuation? Recipe? What if the recipe is a pilsner? Or a simple IPA? Could too much pure o2 cause problems?

Isn't attenuation really controlled by the recipe and the mash temp?  The yeast will do what they will do and assuming you use the same strain repeatedly they should be consistent.  Unless you shock the yeast somehow.

My experience with what I would say are under-attenuated batches is more a factor of an excessively high OG with solid attenuation and good final gravity.  Along the lines of >1.09 down to <1.015. However, the beers are sweeter than they "should" be to match the commercial examples.  To control that, I'm adjusting recipes to bring the OG down a bit so that the beer finishes dryer with the same expected attenuation.

I don't know about over oxygenating.  My understanding, which could be wrong, is that it's pretty hard to over oxygenate.
Title: Re: Quick question about attenuation
Post by: dzlater on February 26, 2014, 10:07:23 PM
I thought session beers were mashed at low temps. to make them drier, and therefore more drinkable?
I mash my low gravity saison, bitter, dry stout, and cream ale at 149f usually for 90 minutes.  They are dry and crisp, but I wouldn't say watery. So if mashed higher they would have better mouthfeel , but not taste too sweet?
Title: Re: Quick question about attenuation
Post by: morticaixavier on February 26, 2014, 10:22:23 PM
I thought session beers were mashed at low temps. to make them drier, and therefore more drinkable?
I mash my low gravity saison, bitter, dry stout, and cream ale at 149f usually for 90 minutes.  They are dry and crisp, but I wouldn't say watery. So if mashed higher they would have better mouthfeel , but not taste too sweet?

Correct, the kind of body/mouthfeel left behind by a less fermentable wort is not sweet, just full and malty. Whereas, underattenuation says to me that the yeast didn't finish with all the (sweeter) fermentable sugars that are there and is less pleasant to me.
Title: Re: Quick question about attenuation
Post by: HoosierBrew on February 26, 2014, 11:21:05 PM
FWIW, Greg Doss found the greatest fermentability at 154F IIRC.
It was 153F for Pils malt. There was a local maximum. Fairly flat at lower temps until 148 or 149, then it increases with the peak at 153, then decreases with a steady slope as the temp increases.

The yeast used will have a big influence, one should consider that also. Greg had data for yeast strains also.

I also believe he conducted his mash for 45 minutes regardless of temperature. I always suspected that you may see the fermentability of the lower-temp mashes in this study increase if they were given more time.



+1.  That's my feeling. While 153F may have proven out in a mash of that duration, I still feel that a 75 -90 minute mash @ 148F wins, in terms of fermentability. Obviously recipe design comes into play heavily regardless.
Title: Re: Quick question about attenuation
Post by: hopfenundmalz on February 27, 2014, 12:00:53 AM
FWIW, Greg Doss found the greatest fermentability at 154F IIRC.
It was 153F for Pils malt. There was a local maximum. Fairly flat at lower temps until 148 or 149, then it increases with the peak at 153, then decreases with a steady slope as the temp increases.

The yeast used will have a big influence, one should consider that also. Greg had data for yeast strains also.

I also believe he conducted his mash for 45 minutes regardless of temperature. I always suspected that you may see the fermentability of the lower-temp mashes in this study increase if they were given more time.



+1.  That's my feeling. While 153F may have proven out in a mash of that duration, I still feel that a 75 -90 minute mash @ 148F wins, in terms of fermentability. Obviously recipe design comes into play heavily regardless.

IIRC he did a test with longer times, 75 minutes at 153F was better than 45 minutes at 153F.

I might have to read that one again.
Title: Re: Quick question about attenuation
Post by: dzlater on February 27, 2014, 12:01:40 AM
I thought session beers were mashed at low temps. to make them drier, and therefore more drinkable?
I mash my low gravity saison, bitter, dry stout, and cream ale at 149f usually for 90 minutes.  They are dry and crisp, but I wouldn't say watery. So if mashed higher they would have better mouthfeel , but not taste too sweet?

Correct, the kind of body/mouthfeel left behind by a less fermentable wort is not sweet, just full and malty. Whereas, underattenuation says to be that the yeast didn't finish with all the (sweeter) fermentable sugars that are there and is less pleasant to me.

So is the goal to have the same % attenuation but a higher FG?
With a mash @ 150, and an OG of 1.039 and an FG of 1.011, thats 72% atten.
You're saying shoot for maybe an FG of 1.016. So I would have to shoot for an OG of 1.057 to wind up at 1.016 with 72% attenuation?
But 1.039 to 1.011 I end up with a 3.7% beer.
and going from 1.057 to 1.016 I end up with 5.4% beer.
Also I can't imagine the styles I listed in my other post would taste better finishing at 1.016.
I'm sure I'm misunderstanding something here?



Title: Re: Quick question about attenuation
Post by: HoosierBrew on February 27, 2014, 12:13:13 AM
FWIW, Greg Doss found the greatest fermentability at 154F IIRC.
It was 153F for Pils malt. There was a local maximum. Fairly flat at lower temps until 148 or 149, then it increases with the peak at 153, then decreases with a steady slope as the temp increases.

The yeast used will have a big influence, one should consider that also. Greg had data for yeast strains also.

I also believe he conducted his mash for 45 minutes regardless of temperature. I always suspected that you may see the fermentability of the lower-temp mashes in this study increase if they were given more time.



+1.  That's my feeling. While 153F may have proven out in a mash of that duration, I still feel that a 75 -90 minute mash @ 148F wins, in terms of fermentability. Obviously recipe design comes into play heavily regardless.

IIRC he did a test with longer times, 75 minutes at 153F was better than 45 minutes at 153F.

I might have to read that one again.

Guess I need to read more on it - I thought the test he did was only @ 45 minutes. Thanks.  I always wondered if the 153F test was like watching 2 top fuel dragsters come off the line - one goes out to an early lead but gets passed at the finish line, with a lower/longer mash temp working better over time. Maybe 153F wins across all time frames.
Title: Re: Quick question about attenuation
Post by: garc_mall on February 27, 2014, 01:22:38 AM
I thought session beers were mashed at low temps. to make them drier, and therefore more drinkable?
I mash my low gravity saison, bitter, dry stout, and cream ale at 149f usually for 90 minutes.  They are dry and crisp, but I wouldn't say watery. So if mashed higher they would have better mouthfeel , but not taste too sweet?

Correct, the kind of body/mouthfeel left behind by a less fermentable wort is not sweet, just full and malty. Whereas, underattenuation says to be that the yeast didn't finish with all the (sweeter) fermentable sugars that are there and is less pleasant to me.

So is the goal to have the same % attenuation but a higher FG?
With a mash @ 150, and an OG of 1.039 and an FG of 1.011, thats 72% atten.
You're saying shoot for maybe an FG of 1.016. So I would have to shoot for an OG of 1.057 to wind up at 1.016 with 72% attenuation?
But 1.039 to 1.011 I end up with a 3.7% beer.
and going from 1.057 to 1.016 I end up with 5.4% beer.
Also I can't imagine the styles I listed in my other post would taste better finishing at 1.016.
I'm sure I'm misunderstanding something here?

The idea is to have a higher FG at the same OG. For Example, my Dark Mild starts at 1.042 and ends at 1.024. Its actually less than 50% AA, and is only 2.6% ABV calculated. It has a full body, but not very much residual sweetness.

If I want a full malt flavor, I mash high for a less fermentable wort, which makes it taste like a bigger beer than it is.

I would mash a table saison low, because crisp/thin and drinkable are a hallmark of the style. Same with the hoppier/drier styles.

Does that make sense?
Title: Re: Quick question about attenuation
Post by: erockrph on February 27, 2014, 01:23:00 AM
I thought session beers were mashed at low temps. to make them drier, and therefore more drinkable?
I mash my low gravity saison, bitter, dry stout, and cream ale at 149f usually for 90 minutes.  They are dry and crisp, but I wouldn't say watery. So if mashed higher they would have better mouthfeel , but not taste too sweet?

Correct, the kind of body/mouthfeel left behind by a less fermentable wort is not sweet, just full and malty. Whereas, underattenuation says to be that the yeast didn't finish with all the (sweeter) fermentable sugars that are there and is less pleasant to me.

So is the goal to have the same % attenuation but a higher FG?
With a mash @ 150, and an OG of 1.039 and an FG of 1.011, thats 72% atten.
You're saying shoot for maybe an FG of 1.016. So I would have to shoot for an OG of 1.057 to wind up at 1.016 with 72% attenuation?
But 1.039 to 1.011 I end up with a 3.7% beer.
and going from 1.057 to 1.016 I end up with 5.4% beer.
Also I can't imagine the styles I listed in my other post would taste better finishing at 1.016.
I'm sure I'm misunderstanding something here?

No, in this case the goal is lower attenuation. When I brew a session beer, I generally want to shoot for the ballpark of what a normal gravity version of the same beer would finish at (or maybe a few points lower, but not by much). I've found that if I get the same attenuation % as a normal-gravity beer, then there isn't enough body and the beer seems thin and watery.

But not all FG's are the same. A beer that was mashed at a higher temp doesn't tend to finish as sweet as a beer that was brewed with more crystal malt but mashed at a lower temp, even though they may finish at the same gravity.
Title: Re: Quick question about attenuation
Post by: klickitat jim on February 27, 2014, 01:32:16 AM
I think the degree of attenuation is influenced by everything. Water, nutrients, pH, grist, mash temp, bla bla , the particular yeast strain itself, and thier health, but in my opinion the greatest contributor is fermentor temp. Namely stability.
Title: Re: Quick question about attenuation
Post by: morticaixavier on February 27, 2014, 06:29:19 AM
I think the degree of attenuation is influenced by everything. Water, nutrients, pH, grist, mash temp, bla bla , the particular yeast strain itself, and thier health, but in my opinion the greatest contributor is fermentor temp. Namely stability.

again though, you're talking about not letting the yeast finish which in under attenuation rather than lower attenuation. a fully attenuated session beer that was done at 55%AA is better in my opinion than a beer that wanted to finish at say 70% but through mishandling was caused to finish at 55% the second one is going to taste sweet and, well, unfinished, while the first will taste malty and finished but with lot's of body and a full mouthfeel.
Title: Re: Quick question about attenuation
Post by: klickitat jim on February 27, 2014, 06:38:55 AM
I think the degree of attenuation is influenced by everything. Water, nutrients, pH, grist, mash temp, bla bla , the particular yeast strain itself, and thier health, but in my opinion the greatest contributor is fermentor temp. Namely stability.

again though, you're talking about not letting the yeast finish which in under attenuation rather than lower attenuation. a fully attenuated session beer that was done at 55%AA is better in my opinion than a beer that wanted to finish at say 70% but through mishandling was caused to finish at 55% the second one is going to taste sweet and, well, unfinished, while the first will taste malty and finished but with lot's of body and a full mouthfeel.

It took me a couple reads, but ya, I fully agree. And, no I wasn't suggesting trying to lower attenuation by fiddling with fermentor temp (didn't intend to anyway) I was pointing out (meant to point out)  that you can dial in everything but if your fermentor is swinging temps very much, all that dialing is for nothing.

Probably that's all a no brainer though. What you are saying is more useful. I know that early on I though sugar was sugar, but it's not really. I don't think unfermentable sugars are perceived as sweet like fermentable sugars are. So leaving fermebtable sugars behind (whatever the cause) would result in a sweeter tasting beer than one that was merely mashed higher but fermented out. Not to mention that under fermentation leaves more than just sugar behind in many cases.

Or so I've heard ???
Title: Re: Quick question about attenuation
Post by: morticaixavier on February 27, 2014, 12:12:07 PM
Gotcha.

Title: Re: Quick question about attenuation
Post by: dzlater on February 27, 2014, 12:51:06 PM
I thought session beers were mashed at low temps. to make them drier, and therefore more drinkable?
I mash my low gravity saison, bitter, dry stout, and cream ale at 149f usually for 90 minutes.  They are dry and crisp, but I wouldn't say watery. So if mashed higher they would have better mouthfeel , but not taste too sweet?

Correct, the kind of body/mouthfeel left behind by a less fermentable wort is not sweet, just full and malty. Whereas, underattenuation says to be that the yeast didn't finish with all the (sweeter) fermentable sugars that are there and is less pleasant to me.

So is the goal to have the same % attenuation but a higher FG?
With a mash @ 150, and an OG of 1.039 and an FG of 1.011, thats 72% atten.
You're saying shoot for maybe an FG of 1.016. So I would have to shoot for an OG of 1.057 to wind up at 1.016 with 72% attenuation?
But 1.039 to 1.011 I end up with a 3.7% beer.
and going from 1.057 to 1.016 I end up with 5.4% beer.
Also I can't imagine the styles I listed in my other post would taste better finishing at 1.016.
I'm sure I'm misunderstanding something here?

The idea is to have a higher FG at the same OG. For Example, my Dark Mild starts at 1.042 and ends at 1.024. Its actually less than 50% AA, and is only 2.6% ABV calculated. It has a full body, but not very much residual sweetness.

If I want a full malt flavor, I mash high for a less fermentable wort, which makes it taste like a bigger beer than it is.

I would mash a table saison low, because crisp/thin and drinkable are a hallmark of the style. Same with the hoppier/drier styles.

Does that make sense?

That makes sense.
I've just seen so many mentions about mashing low gravity beers @ high mash temps. But usually no one ever mentions the style of low gravity beer.
So the whole high mash temp for low gravity beers, isn't for every style.
It seems to me  just use higher mash temps. for a more malty beer whatever the gravity?

Title: Re: Quick question about attenuation
Post by: erockrph on February 27, 2014, 01:37:46 PM
I thought session beers were mashed at low temps. to make them drier, and therefore more drinkable?
I mash my low gravity saison, bitter, dry stout, and cream ale at 149f usually for 90 minutes.  They are dry and crisp, but I wouldn't say watery. So if mashed higher they would have better mouthfeel , but not taste too sweet?

Correct, the kind of body/mouthfeel left behind by a less fermentable wort is not sweet, just full and malty. Whereas, underattenuation says to be that the yeast didn't finish with all the (sweeter) fermentable sugars that are there and is less pleasant to me.

So is the goal to have the same % attenuation but a higher FG?
With a mash @ 150, and an OG of 1.039 and an FG of 1.011, thats 72% atten.
You're saying shoot for maybe an FG of 1.016. So I would have to shoot for an OG of 1.057 to wind up at 1.016 with 72% attenuation?
But 1.039 to 1.011 I end up with a 3.7% beer.
and going from 1.057 to 1.016 I end up with 5.4% beer.
Also I can't imagine the styles I listed in my other post would taste better finishing at 1.016.
I'm sure I'm misunderstanding something here?

The idea is to have a higher FG at the same OG. For Example, my Dark Mild starts at 1.042 and ends at 1.024. Its actually less than 50% AA, and is only 2.6% ABV calculated. It has a full body, but not very much residual sweetness.

If I want a full malt flavor, I mash high for a less fermentable wort, which makes it taste like a bigger beer than it is.

I would mash a table saison low, because crisp/thin and drinkable are a hallmark of the style. Same with the hoppier/drier styles.

Does that make sense?

That makes sense.
I've just seen so many mentions about mashing low gravity beers @ high mash temps. But usually no one ever mentions the style of low gravity beer.
So the whole high mash temp for low gravity beers, isn't for every style.
It seems to me  just use higher mash temps. for a more malty beer whatever the gravity?

Style is a factor, but I wouldn't apply that rule across the board. I wouldn't mash a big dopplebock at 162 (for example), it would just end up too thick and heavy.
Title: Re: Quick question about attenuation
Post by: dzlater on February 27, 2014, 01:55:48 PM
  If I brew a beer with an og of 1.050 and an fg of 1.012, and use a yeast that is estimated at 75% att. That's a fully attenuated beer.
If I brew the same beer with a yeast that is rated at 60% attenuation and I achieve that 60% winding up with a fg of 1.020. Is the beer underattenuated because it could go further, or is it fully attenuated because it has reached the limit of the yeast? And wouldn't it be sweeter because there are more unfermented sugars?
  By the same token if I brew the same beer but use a higher mash temp. so the yeast rated for 75% only attenuates to 60% is that fully attenuated because it's reached it's limit due to less unfermentables.
 To much time off from work is leaving me to much time to think about all this.
Title: Re: Quick question about attenuation
Post by: garc_mall on February 27, 2014, 03:16:58 PM
  If I brew a beer with an og of 1.050 and an fg of 1.012, and use a yeast that is estimated at 75% att. That's a fully attenuated beer.
If I brew the same beer with a yeast that is rated at 60% attenuation and I achieve that 60% winding up with a fg of 1.020. Is the beer underattenuated because it could go further, or is it fully attenuated because it has reached the limit of the yeast? And wouldn't it be sweeter because there are more unfermented sugars?
  By the same token if I brew the same beer but use a higher mash temp. so the yeast rated for 75% only attenuates to 60% is that fully attenuated because it's reached it's limit due to less unfermentables.
 To much time off from work is leaving me to much time to think about all this.

The beer is underattenuated if there are fermentable sugars left after yeast activity is "finished," regardless of the numbers.

The yeast "rating" is based off a general (lab-specific) wort, and is really only comparable on a general level (low attenuation, high attenuation), and I don't trust the numbers given.

If I felt I had an underattenuated wort, I would probably do a forced ferment test, and see if it could go any lower. When I taste beers that are underattenuated (I know a small micro that cold crashes about 3/4 through fermentation to "preserve the sweetness") I generally get that from extra sweetness that tastes like it isn't supposed to be there.
Title: Re: Quick question about attenuation
Post by: morticaixavier on February 27, 2014, 03:37:25 PM
  If I brew a beer with an og of 1.050 and an fg of 1.012, and use a yeast that is estimated at 75% att. That's a fully attenuated beer.
If I brew the same beer with a yeast that is rated at 60% attenuation and I achieve that 60% winding up with a fg of 1.020. Is the beer underattenuated because it could go further, or is it fully attenuated because it has reached the limit of the yeast? And wouldn't it be sweeter because there are more unfermented sugars?
  By the same token if I brew the same beer but use a higher mash temp. so the yeast rated for 75% only attenuates to 60% is that fully attenuated because it's reached it's limit due to less unfermentables.
 To much time off from work is leaving me to much time to think about all this.

The beer is underattenuated if there are fermentable sugars left after yeast activity is "finished," regardless of the numbers.

The yeast "rating" is based off a general (lab-specific) wort, and is really only comparable on a general level (low attenuation, high attenuation), and I don't trust the numbers given.

If I felt I had an underattenuated wort, I would probably do a forced ferment test, and see if it could go any lower. When I taste beers that are underattenuated (I know a small micro that cold crashes about 3/4 through fermentation to "preserve the sweetness") I generally get that from extra sweetness that tastes like it isn't supposed to be there.

Right,

the yeast attenuation numbers are guidelines and do not reflect the real world all that well. I've had low attenuators finish >75% and high attenuators that finish <70%. There are some yeasts strains that seem able to ferment sugars that others are simply not capable of. Actually there are DEFINITELY strains like that. Ale yeast in general is largely defined by it's ability to ferment rafinose while Lager yeast can't. (I think i got that right  but smarter folks will chime in to correct me if I didn't, ITIGTRBSFWCITCMIID?) similarly brett will ferment WOOD if given enough chance and nothing else to eat. But with the standard ale yeast species it's not as clear cut as AA% would lead you to believe
Title: Re: Quick question about attenuation
Post by: hopfenundmalz on February 27, 2014, 03:52:09 PM
The CAMRA books I have have the mash temp for milds at 153F, but those generally have other things like a god amount of crystal malt or wheat to aid the body. If you look at the NHC award winners that were milds those go to 156F.

I also will be contrarian in that if I want a malty beer I do that with the malts selected, and malty does not equal sweet. You can have a malty beer that is fully attenuated, Oktoberfests come to mind.

For some British beers, more crystal is not out of place. One should also think about mild ale malt, amber malt, and broom brown malt for some of those beers. Bitterness levels and water chemistry can also be adjusted to give a dryness to a beer.

Uncle Jeff's $0.02 on this.
Title: Re: Quick question about attenuation
Post by: ynotbrusum on February 28, 2014, 03:00:35 AM
The CAMRA books I have have the mash temp for milds at 153F, but those generally have other things like a god amount of crystal malt or wheat to aid the body. If you look at the NHC award winners that were milds those go to 156F.

I also will be contrarian in that if I want a malty beer I do that with the malts selected, and malty does not equal sweet. You can have a malty beer that is fully attenuated, Oktoberfests come to mind.

For some British beers, more crystal is not out of place. One should also think about mild ale malt, amber malt, and broom malt for some of those beers. Bitterness levels and water chemistry can also be adjusted to give a dryness to a beer.

Uncle Jeff's $0.02 on this.

Agreed Jeff.  Think Bock - it is fully attenuated, but malty.
Title: Re: Quick question about attenuation
Post by: denny on February 28, 2014, 04:39:36 PM

Agreed Jeff.  Think Bock - it is fully attenuated, but malty.

Or Ayinger dunkel.