[tygo]

I do, however, raise the grainbed temp to 170 with my batch spare infusion. I would think this would do a lot to halt enzymatic activity.

Not for the enzymes that are already in the boil kettle from the initial batch sparge runoff.

[Pawtucket Patriot]

I do, however, raise the grainbed temp to 170 with my batch spare infusion. I would think this would do a lot to halt enzymatic activity.

Not for the enzymes that are already in the boil kettle from the initial batch sparge runoff.

Ok, that seems to make sense. But assuming I've got full conversion by the end of the mash, is the fermentability profile of the first runnings really changing in the kettle?

[tygo]

I do, however, raise the grainbed temp to 170 with my batch spare infusion. I would think this would do a lot to halt enzymatic activity.

Not for the enzymes that are already in the boil kettle from the initial batch sparge runoff.

Ok, that seems to make sense. But assuming I've got full conversion by the end of the mash, is the fermentability profile of the first runnings really changing in the kettle?

I don't really know but I've given it some thought when I was experiencing a similar issue.  If you don't mash out there's going to be some amount of beta still active in the first runnings.  And the temperature of the first runnings in the kettle is somewhere around 140F for me.  It takes me a good amount of time to finish the runoff so I think it's possible the fermentability profile is still changing.

Like you, I attempt a mashout infusion or decoction with every batch but I don't always hit a high enough mash out temp to ensure that I'm denaturing everything.  Although when I started doing that it did seem to help my over-attenuation issues somewhat.

[denny]

But if you're batch sparging, you get to a boil within a few minutes.  It's not like fly sparging where you're waiting n hour or so before the boil.

[narvin]

I did a rough estimate with Mr Malty and you're pitching close to 2 million cells/ml/P.  You could cut back on the yeast a bit and still get a complete and healthy lager fermentation but perhaps with slightly lower attenuation.  1.5 mil/ml/P is the "standard" that gets thrown around a lot, and this is usually when repitching yeast from a previous batch which may not be as viable as the yeast from a starter.

[malzig]

If your beers are attenuating more than you would like, why not just raise the mash temperature a few degrees?

[Pawtucket Patriot]

I did a rough estimate with Mr Malty and you're pitching close to 2 million cells/ml/P.  You could cut back on the yeast a bit and still get a complete and healthy lager fermentation but perhaps with slightly lower attenuation.  1.5 mil/ml/P is the "standard" that gets thrown around a lot, and this is usually when repitching yeast from a previous batch which may not be as viable as the yeast from a starter.

Huh, you're right.  I guess I hadn't consulted with Mr. Malty for a while.  I'll try reformulating my starter volume slightly to more closely approximate Mr. Malty's recommendation.

[denny]

I did a rough estimate with Mr Malty and you're pitching close to 2 million cells/ml/P.  You could cut back on the yeast a bit and still get a complete and healthy lager fermentation but perhaps with slightly lower attenuation.  1.5 mil/ml/P is the "standard" that gets thrown around a lot, and this is usually when repitching yeast from a previous batch which may not be as viable as the yeast from a starter.

Huh, you're right.  I guess I hadn't consulted with Mr. Malty for a while.  I'll try reformulating my starter volume slightly to more closely approximate Mr. Malty's recommendation.

I'm not sure that there's any connection.  If you pitch too little yeast, I could see some issues.  But if you pitch more (or too much), the wort will still attenuate to it's limit of fermentability but no further, no matter how much yeast there is.  More yeast will not equal more attenuation unless you're underpitching to start with.

[narvin]

I'm not sure that there's any connection.  If you pitch too little yeast, I could see some issues.  But if you pitch more (or too much), the wort will still attenuate to it's limit of fermentability but no further, no matter how much yeast there is.  More yeast will not equal more attenuation unless you're underpitching to start with.

You may be (probably are) right, Denny.  I was under the impression that the attenuation limit that you see in a fast ferment test is higher than what you actualy get when pitching the standard amount of yeast.  But I doubt he's really overpitching enough to see that much of a difference.  Still, I wouldn't overpitch if I were getting too much attenuation.

[denny]

You may be (probably are) right, Denny.  I was under the impression that the attenuation limit that you see in a fast ferment test is higher than what you actualy get when pitching the standard amount of yeast.  But I doubt he's really overpitching enough to see that much of a difference.  Still, I wouldn't overpitch if I were getting too much attenuation.

But I don't think the attenuation limit is affected by the amount of yeast.  The speed of fermentation is.  I mean, if the quantity of yeast was the key, it would seem like if you pitched enough yeast you could attenuate to negative numbers!

[narvin]

You may be (probably are) right, Denny.  I was under the impression that the attenuation limit that you see in a fast ferment test is higher than what you actualy get when pitching the standard amount of yeast.  But I doubt he's really overpitching enough to see that much of a difference.  Still, I wouldn't overpitch if I were getting too much attenuation.

But I don't think the attenuation limit is affected by the amount of yeast.  The speed of fermentation is.  I mean, if the quantity of yeast was the key, it would seem like if you pitched enough yeast you could attenuate to negative numbers!

Right, I definitely don't think the attenuation limit is affected by the amount of yeast; it's the, well, limit.  

But I didn't think most healthy fermentations actually made it all the way to the attenuation limit. Even if you're only a point or two away, that's significant percentage-wise in a 12P beer.

[bluesman]

Matt...have you decided on a path forward yet? I assume you're going to try increasing your mash temp. I still think this is your issue. In ant event...let us know how you make out with this humdinger.

[Pawtucket Patriot]

Matt...have you decided on a path forward yet? I assume you're going to try increasing your mash temp. I still think this is your issue. In ant event...let us know how you make out with this humdinger.

I have a few thoughts.  Increasing mash temps for single infusions will likely be the first thing I try.  Also, when I've done decoction mashes for German-style beers with all-base-malt grists, overattenuation is not an issue.  For example, my 12P Helles finishes at 1.010 when I do a Hockhurz double decoction mash.

I'll be brewing another Munich Dunkel 99% base malt grist) in a few weeks using a Hockhurz decoction mash.  I'll post my attenuation results.

[mattc]

Can you tell us of any departures from your traditional brewing method? Anything new?

I have changed a few things over the past year. First, I changed the way I approach water adjustments. Instead of using chalk to raise mash pH, I now only use pickling lime. Also, I add fewer flavor ions in the kettle than I had before. I usually try to track the suggested style profiles on Bru'n Water (e.g., yellow balanced, brown malty, etc.) rather than trying to emulate "published" city profiles.

Second, I use acid malt exclusively for lowering mash pH. I add 1% acid malt to lower mash pH by .1. Again, measuring with colorpHast strips, I am almost always within .1 of my pH target, which is 5.4.

I personally agree with all of the changes you have made. I'm sure that they have made your beers much better,(short of the attenuation problem). I too have made a point to add less and less minerals back to my water than nessecary. ( I have very soft water anyway), and rely on acid malt to drop PH when I need to.

To address you problem I would make sure my ph is close to 5.4 and try to rasie my mash temp up to 154-156 dpending on how "chewy" you like your beers to be. Its probably something as simple as these 2 things

[Pawtucket Patriot]

I'm getting increasingly frustrated about this attenuation issue.  I just took a final gravity reading for my recent BoPils and it's 1.007 (I was estimating 1.014).  Here was my recipe/process:

5.33 gallon batch
6.25# Weyermann floor-malted bohemian pilsner
2.25# Best Malz Pilsner
.50# Cara Pils
.30# Acid malt

Mash program
Infuse w/18 qts H2O ==> Beta rest @ 145 for 25 minutes
Pull thick 8.5-qt decoction; raise to 158 and hold for 15 minutes
Boil thick decoction for 30 minutes
Remix thick decoction and raise main mash to Alpha rest @ 158 for 40 minutes
Pull thin 6.5-qt decoction and raise to boiling
Remix thin decoction and raise main mash to mashout temp @ 168 for 10 minutes

Mash pH was 5.4 throughout.

I pitched only the slurry from a 1.5L stirplate starter made from 2 smackpacks of Wyeast 2001.  I fermented between 50-52 degrees for 14 days; the gravity was 1.012-1.013 on the 14th day of fermentation.  I removed the fermenter from the cooling chamber and let it sit at 65 degrees for a 48-hour diacetyl rest.  I then placed the fermenter back in the cooling chamber and gradually cooled the beer 5 degrees per day until I reached lagering temp.

Here are some nagging thoughts about my decoction procedure:

I mash in a 52-qt rectangular cooler, which means I can't directly heat my mash.  This means that after I pull my first decoction, the main mash temp will stay around the low 140s until I add back the decoction.  This can take up to an hour, depending on how long I boil the decoction.  Will leaving the main mash at beta temps for that long basically set the fermentability of my wort?  In other words, even if I raise the main mash to alpha temps after adding back the decoction, will the alpha rest actually make the wort less fermentable?  Or am I stuck with a highly fermentable wort that sat at beta temps for a prolonged period of time?  If my wort profile is basically set by the time I add back the thick decoction, it makes sense that my beers would be more attenuated (since the alpha rest isn't really doing much).  As such, I might be better off just trying to hit my steps with infusions, since I can manipulate the rest times better that way given my setup.

Any thoughts/suggestions are much appreciated.