[alan_marks59]

Jill,

Thank you for your response and checking into this matter.This clarifies things greatly. I wouldn't have been so concerned normally; since it was the cover story for the issue it really had me scratching my head.

Thank you to all that responded for your assistance and passion for brewing.

It's my day off from the restaurant...time to dough in...

Alan

[Tim McManus]

I'm thinking he meant melanoidins or the perception of malt sweetness.

That's what I was wondering about.  I'd think there would actually be fewer dextrins, but I'm not certain.  I'm guessing that whatever added "sweetness" there might be would be due to Maillard reactions, not dextrins.

It was a little of both.  Definitely had some Maillard reaction stuff going on, easily identified in the flavor.  However, and I don't have the recipe details in front of me right now, it didn't ferment all the way out as we had expected.  The gravity was still high (1.100 fermented down to 1.068), and we used a high-gravity lager yeast (yes, made a starter; yes, starter was chilled and pitched into the wort at around 50°F; yes, aerated with oxygen).  My assumption was that there were residual dextrins in the wort that weren't fermented out.

I'll have to check the recipe details to be sure.

[denny]

It was a little of both.  Definitely had some Maillard reaction stuff going on, easily identified in the flavor.  However, and I don't have the recipe details in front of me right now, it didn't ferment all the way out as we had expected.  The gravity was still high (1.100 fermented down to 1.068), and we used a high-gravity lager yeast.  My assumption was that there were residual dextrins in the wort that weren't fermented out.

I'll have to check the recipe details to be sure.

OK, but why would that be due to decoction?  Or did I misunderstand you?

[Tim McManus]

It was a little of both.  Definitely had some Maillard reaction stuff going on, easily identified in the flavor.  However, and I don't have the recipe details in front of me right now, it didn't ferment all the way out as we had expected.  The gravity was still high (1.100 fermented down to 1.068), and we used a high-gravity lager yeast.  My assumption was that there were residual dextrins in the wort that weren't fermented out.

I'll have to check the recipe details to be sure.

OK, but why would that be due to decoction?  Or did I misunderstand you?

Nope, you understood correctly.  The "Why" part is subject to debate.  We had 4 steps, 122°F, 148°F, 156°F and 168°F.  Went through each during each phase of decoction, 15 minutes a step per phase.

It shouldn't have extracted so many dextrins, but it did.  We tend to have beers ferment out from OG 1.060 to FG 1.020 and higher with a triple-D or decoct-infusing.  So somewhere we're getting something that is increasing the body of the wort, and my assumption is that it's dextrins coming from the decocting.

[denny]

But are there dextrins produced by the decoction?  And if so, how?

[Tim McManus]

But are there dextrins produced by the decoction?  And if so, how?

If I had to guess, it would be due to this:

"A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion, but the resultant sugars are less fermentable and will result in a sweeter, maltier beer."

From http://www.howtobrew.com/section3/chapter14-6.html

Since I am pulling out the thickest part of the mash for each decoction, that volume will produce more less fermentable sugars if Palmer is correct.  I should pull out Noonan's book and cross reference, but this would be where I would start looking for additional dextrins.

Oh, and to note, we can pull out up to 40% of the mash for a decoction step, so that is a good amount of mash volume and could be what's contributing to the significant rise in dextrins.

[denny]

If I had to guess, it would be due to this:

"A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion, but the resultant sugars are less fermentable and will result in a sweeter, maltier beer."

From http://www.howtobrew.com/section3/chapter14-6.html

Since I am pulling out the thickest part of the mash for each decoction, that volume will produce more less fermentable sugars if Palmer is correct.  I should pull out Noonan's book and cross reference, but this would be where I would start looking for additional dextrins.

Thanks for that, but I don't know if that really makes much difference.  At least in my experience, it's a stretch to relate mash thickness to wort profile in more than a very minor way.

[jeffy]

If I had to guess, it would be due to this:

"A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion, but the resultant sugars are less fermentable and will result in a sweeter, maltier beer."

From http://www.howtobrew.com/section3/chapter14-6.html

Since I am pulling out the thickest part of the mash for each decoction, that volume will produce more less fermentable sugars if Palmer is correct.  I should pull out Noonan's book and cross reference, but this would be where I would start looking for additional dextrins.

Thanks for that, but I don't know if that really makes much difference.  At least in my experience, it's a stretch to relate mash thickness to wort profile in more than a very minor way.

On the other hand, if one pulls a thick decoction of 40% and raises that to high sacc rest of 156-160F, then that would account for it, eh?

[a10t2]

On the other hand, if one pulls a thick decoction of 40% and raises that to high sacc rest of 156-160F, then that would account for it, eh?

Wouldn't it be the other way around? The thicker the decoction, the more wort is left in the mash, and the fewer enzymes are denatured by boiling. That's why it's generally recommended to pull the thickest decoction you can manage.

Tim: What was the grist? If it was enzymatically weak then 15 min rests might not have been enough for full conversion regardless of the method used. Either way, I'm with Denny - I've only done a few decoctions, but I've seen *increased* fermentability as a result. For a beer to stop at 1.068 I think some other factor would have to be in play. Did you do a forced ferment test?

[Tim McManus]

On the other hand, if one pulls a thick decoction of 40% and raises that to high sacc rest of 156-160F, then that would account for it, eh?

Wouldn't it be the other way around? The thicker the decoction, the more wort is left in the mash, and the fewer enzymes are denatured by boiling. That's why it's generally recommended to pull the thickest decoction you can manage.

Tim: What was the grist? If it was enzymatically weak then 15 min rests might not have been enough for full conversion regardless of the method used. Either way, I'm with Denny - I've only done a few decoctions, but I've seen *increased* fermentability as a result. For a beer to stop at 1.068 I think some other factor would have to be in play. Did you do a forced ferment test?

10-gallon batch

2# Rice hulls
20# Munich Malt
12.5# Vienna Malt
6.25# Dark Munich Malt

Decoction Steps:

100°F
127°F
149°F
168°F

We used Wyeast Bavarian Lager #2206 to ferment with.  It's a temperamental strain, but we had a good starter and a strong ferment.

We did not do a force ferment test, and I'm not sure what that exactly is.

[blatz]

looks pretty enzymatically weak to me - the vienna and light munich should be okay on their own, but IIRC, the dark munich has a DP of 25 (assuming weyermann or best - I think its lower with some other brands). 

That grist needs some pils malt, or much longer rests...

[a10t2]

I'd put money on that mash being low in enzyme content. Do you have the actual lot analyses? It would probably hinge mostly on the DP of the Vienna. Munich I can be <50 Lintner, and Munich II <20. Unless the Vienna was very high (>100) then the mash as a whole would be <60 and 15 min probably wouldn't be enough time for conversion to finish.

A forced ferment test is simply reserving a small portion of the wort, pitching several times as much yeast as normal, and fermenting it warm (on a stir plate if available) so that you can determine the FG after just a couple days.

FWIW I haven't found 2206 to be temperamental, and I've certainly never had it stall out significantly above the FFT result.

Edit: Paul beat me to it...

[denny]

Yep, I agree with everything Paul and Sean have said.  Especially the part about 2206 not being temperamental.

[Tim McManus]

Each decoction step varied, but the temperature steps in between them were 15 minutes.  Tough to explain, but this might help:

Mash Temp
100°F - decoction removed, heated to 127°F, held for 15 minutes, raised to 149°F, held for 15 minutes, raised to 167°F, held for 15 minutes, boiled for 15 minutes, returned to mash
127°F - decoction removed, heated to 149°F, held for 15 minutes, raised to 167°F, held for 15 minutes, boiled for 15 minutes, returned to mash
149°F - decoction removed, heated to 167°F, held for 15 minutes, boiled for 15 minutes, returned to mash
167°F - , held for 15 minutes, mash out

So each mash step held the temperature for longer than 15 minutes, but the decoction steps were held for 15 minutes each, if that helps with the explanation.  Our saccrification should have occurred optimally at 149°F and was held for at least 30 minutes.

I got the feeling 2206 was temperamental from Designing Great Beers.  Although it isn't called out by name and manufacturer, I interpreted it as the yeast we were using, 2206.  We took extra care to cool the starter and pitch at near fermentation temperature (wort was chilled to the same fermentation temp. as the starter).

Good to know about the enzymes.  At least now I know where to focus next in formulating the recipe.  Any grain suggestions to augment the low enzymes?  I don't have the lot analysis.

[a10t2]

Good to know about the enzymes.  At least now I know where to focus next in formulating the recipe.  Any grain suggestions to augment the low enzymes?  I don't have the lot analysis.

If the base malt is anything other than a pale or pilsner malt, and you don't have the lot analysis for it, I'd use the lightest-colored base malt that would be stylistically appropriate to make up at least 20% of the fermentables. In this case that would be your pilsner malt of choice. In an ale, probably a domestic 2-row pale malt.