Under Attenuation on an Almost 100% Munich Beer

[Steady-Hopper]

I've reached 1.025 after 14 days with saflager S-23. 10 days at 40, and 4 days at 60. I aerated properly and pitched a healthy 11g sachet of yeast onto 3 gallons of wort. The beer tastes great and has no off flavours, and any fermentation seems to be done. My problem is it's still so thick. I think it may be the specific munich malt I was using (Gambrinus light). Any advice?

Recipe (roughly)

94% Gambrinus Munich
4% Caramunich type II
2% Carafa Type II

28ibus Tettnanger @ 60 minutes.

 

[jaydlaw]

Someone Else could verify but your aren't going to get as high of an attenuation with darker malts.

 

[andrewmaixner]

Did you mash at 158F? 144F?

Verified mash conversion with iodine starch test?

Have you measured attenuation 3 days apart to very no continuing fermentation?

What was original gravity? You mention % but no amount for grist -- so was this a 1.050 or a 1.100?

 

[giraffe]

Also how long did you mash? Some munich malts can make less fermentable worts than expected, i often add 15% pils to all 8-10L munich grists as insurance. Ive never used the gambrinus munich, but ive had problems with others. Even if the mash fully converted, beta-amalyase denatures in 30 or so min even in the 140s. And some munich malts just dont have a high level of enzymes. (Im not positive that is the correct explanation, but i am positive, sometimes all munich malt grists come out more unfermentable than expected)

 

[Steady-Hopper]

90 minute mash @ 148. Wort ran clear and didn't taste starchy, so I'm assuming there was no starch left. 1.051 og. I understand the whole lower diastatic power dark malt thing, but i'm sure it converted.

 

[motobrewer]

that seems suspect. i've used 100% continental munich (best malz) in beers before and always get decent attenuation levels, but i'll always do a double decoction.

 

[giraffe]

Gambrinus light is 10L which is the equivalent of a dark continental munich. Im still going to go with a lack of beta amalayse, led to too much of the starches being broken down by alpha amalyze leading to a more dextrinous wort than the mash temp would usually give.

 

[Steady-Hopper]

How could I avoid this in future brews - cut it with some pils? Also, would Brett be able to chew through the residual sugars? Would it over pronounce the 28 ibus and make it undrinkable? I've never used Brett and been aching to pitch some Orval dregs. An Oud Bruin lager?

 

[motobrewer]

check your equipment, maybe do an iodine test next time. what does "starchy wort" taste like anyway?

 

[giraffe]

How could I avoid this in future brews - cut it with some pils? Also, would Brett be able to chew through the residual sugars? Would it over pronounce the 28 ibus and make it undrinkable? I've never used Brett and been aching to pitch some Orval dregs. An Oud Bruin lager?

Using 10-20% pils is one way. Or using like 40% of a 6L munich. Use a more attenuative lager yeast possibly s-23 isnt the most foolproof yeast. I really wouldnt add brett, youd likely taste it in a lager. Try a different brand of munich malt. also check your equipment/thermometers, etc.

But you did say it tasted good? If so id roll with it, 1.024 isnt soo high, to be undrinkable. Id just lager it for 6 weeks and let it mellow, it may drop a point or two as it goes.

 

[Steady-Hopper]

Using 10-20% pils is one way. Or using like 40% of a 6L munich. Use a more attenuative lager yeast possibly s-23 isnt the most foolproof yeast. I really wouldnt add brett, youd likely taste it in a lager. Try a different brand of munich malt. also check your equipment/thermometers, etc.

But you did say it tasted good? If so id roll with it, 1.024 isnt soo high, to be undrinkable. Id just lager it for 6 weeks and let it mellow, it may drop a point or two as it goes.

It's not that it's bad; it's just not what I wanted. I brewed up a bock today and pitched it on top of the dunkel's dregs. I'll have to see if I get the same attenuation - about 30% of the recipe is pils malt. Usually s-23 gets about 78% attenuation with me, in regular recipes. Also, I realise I would taste the brett, and I thought maybe it would taste good. If I can get it to 1.020, I'll be a happy camper.

I always thought it was safe to brew a 100% Munich beer if the malt was less than 10L, and that attenuation would be the typical in the 75% range. I have about 40lbs of this stuff left. Has anybody tried brewing a full Munich beer before; what were the results like?

 

[Bellybuster]

I do all munich all the time...yummm. Doing one tomorrow. 1.060 all munich. Never have issues converting. I even do it with lager yeast, all munich lager s amazing
You should have had full conversion at 90 minute mash. I would suggest a yeast change is in order maybe but s-23 should ferment that down to the 1.012-15 ballpark
I tend to use Wyeast bavarian lager 2206. It specs out at 78% but I routinely see over 80% attenuation.

You can safely try bringing the beer up to 70 and see if it starts back up. It might.

 

[Steady-Hopper]

I do all munich all the time...yummm. Doing one tomorrow. 1.060 all munich. Never have issues converting. I even do it with lager yeast, all munich lager s amazing
You should have had full conversion at 90 minute mash. I would suggest a yeast change is in order maybe but s-23 should ferment that down to the 1.012-15 ballpark
I tend to use Wyeast bavarian lager 2206. It specs out at 78% but I routinely see over 80% attenuation.

You can safely try bringing the beer up to 70 and see if it starts back up. It might.

What brand Munich? I don't think conversion was the problem for me - but I am betting it was something mash/malt related. A decoction probably would have helped, and maybe I'll try my hand at one in the future. I doubt it was the yeast. I've fermented 5 gallon, 1.060 beers with one sachet and it came out with 75% attenuation. People don't give s-23 a fair chance IMO.

 

[Bellybuster]

I've used Breiss but my fave is Canada malting Munich.
Decoction should not be necessary, Munich under 10L is a base malt. More than capable of converting itself. I tend to brew to 1.055 and hope for 1.010-15.
Munich does very well as a heavy high alcohol beer as well. The extreme maleness measures out the alcohol.

 

[Steady-Hopper]

I've used Breiss but my fave is Canada malting Munich.
Decoction should not be necessary, Munich under 10L is a base malt. More than capable of converting itself. I tend to brew to 1.055 and hope for 1.010-15.
Munich does very well as a heavy high alcohol beer as well. The extreme maleness measures out the alcohol.

What's your mash temp and length? Maybe I'l try my luck at a Baltic porter. I really think it's this specific Munich malt that's causing me trouble. I don't know of anyone doing a SMASH with Gambrinus Munich.

 

[Bellybuster]

I'll be brewing this today at 152 degrees.
Maybe try tossing in a pound of 2 row, it won't change the taste at all.

 

[specharka]

I just brewed a doppelbock that was 75% Briess Munich 10L, 20% Pils, and 5% CaraMunich/Chocolate malt, and I had no trouble attenuating whatsoever. Used a double decoction, 140-156-168 mash schedule, 60 minute sacc rests. Used a 3L starter of Saflager W-34/70, pitched to 48F wort, and allowed to rise to 68F after 10 days for a diacetyl rest. After 14 days, beer went from 1.083 to 1.023, and is still fermenting.

My guess is you fermented way too low (I didn't even think 40F was possible to ferment) and possibly didn't pitch enough yeast. Munich I will convert all of its starches to sugars, if given the opportunity...which it looks like you did.

 

[Bellybuster]

Just noticing this, 40 is way to low for primary, good call by specharka. Even so, the warm up to 60 should have spurred fermentation.

 

[giraffe]

Oh woah, I didnt notice 40 for primary either. S-23 should have a primary fermentation temp around 52. 40 is way too low.

 

[Bellybuster]

ya I missed it too.

Is this beer still in the fermenter? If so leave it for awhile at a reasonable temp, it'll ferment out more than likely

 

[Steady-Hopper]

I meant 49 - typing too fast. I realise that's still pretty low though. It looked fairly active at a tempt that low. It perked right up when I did a diacetly rest, but I doubt it ate through the right amount of sugars. I'm afraid to bottle this and think I would easily get some bottle bombs. Maybe repitch some yeast, warm it up and see what happens? I left it at about 65 degrees for 2 days and there were absolutely no visible signs of refermentation.

EDIT: I've already transferred it off the yeast cake. Perhaps another dose of yeast would be in order?

 

[andrewmaixner]

Sure, make a starter and pitch it all in once it shows signs of activity. Can't hurt.

 

[Steady-Hopper]

So, just took a gravity reading. It's dropped to 1.020 since last reading, and I'm keeping it at 60-65 degrees right now. Perhaps I just fermented too cold? The Saflager sachet says: 48.2- 71.6 and ideally 53-59. I assumed 45-48 was okay for a lager - my bad. Will take another reading in a week or so. Hopefully it drops. I have an expired pack of US-05 that i'll pitch if nothing else is happening.

Also, if anyone could recommend either a multi infusion mash schedule or a decoction mash schedule for 100% Munich beers that would be great. Even if mashing wasn't the problem, this experience has made me completely reevaluate how I think about mashing. BTW, care to share some good Munich recipes?

 

[giraffe]

There is debate weather a 131 protien rest is useful for fully modified malts. I think so, but there is disagreement.

I think doing a split saccrification rest is a good idea with most lagers. The idea is you do two rests, one in the low to mid 140s for beta-amylaze activity, and one in the high 150s for alpha-amalyaze.

beta-amalyaze breaks down fairly rapidly over 152, but even in the 140s, it only lasts 30-40 minutes once its in solution. So doing a rest at 144 ish, and then varying the time (or the rest temp-- towards 152 beta amalyaze will work slower) for how much beta-amalyze activity you want. For a dry lager you'd go 30-40 minutes. Then raise it to the high 150s to break down the rest of the starches that are left. Remember, lager yeasts arent as attenuative as ale yeasts in general, yet we tend to want lager on the drier side compared with a pale ale or brown ale. So you need to mash lower to get there.

http://braukaiser.com/wiki/index.php?title=Infusion_Mashing there is also a good decoction mashing article on the site as well.

 

[andrewmaixner]

So, just took a gravity reading. It's dropped to 1.020 since last reading, and I'm keeping it at 60-65 degrees right now. Perhaps I just fermented too cold? The Saflager sachet says: 48.2- 71.6 and ideally 53-59. I assumed 45-48 was okay for a lager - my bad. Will take another reading in a week or so. Hopefully it drops. I have an expired pack of US-05 that i'll pitch if nothing else is happening.

Also, if anyone could recommend either a multi infusion mash schedule or a decoction mash schedule for 100% Munich beers that would be great. Even if mashing wasn't the problem, this experience has made me completely reevaluate how I think about mashing. BTW, care to share some good Munich recipes?

I'd say that you figured it out.

 

[Steady-Hopper]

As of right now, I'm somewhat confident temperature was the problem- which is strange as I've fermented S-23 at temps like this before with good results. I also pitched at around 70 (a sin I know. It was too hard to get my temps down). Thanks so much, and I will update later.

 

[TAK]

Sounds like the root cause may have been identified. As I was reading through though, it reminded me of something I was thinking about trying sometime. I've considered doing a (near) 100% Munich lager, but thought about throwing in a 1lb or so of 6-row. 6-row has higher enzymatic power than 2-row, right? I figure that'd help convert everything well and help dry it out.

 

[Bellybuster]

my 100% munich is fermenting right now. will let you know how it goes. Mashed at 152, Bavarian Lager yeast. almost 30 hours lag to get moving but its at 49deg so no worries.
I have never had issue getting 100% Munich to ferment out. Methinks your temp was the issue.
Look forward to a great beer that always tastes like more

 

[Steady-Hopper]

Update

The Dunkel I brewed has not dropped another point and has stabilised at 1.020 with 60% attenuation since November 20th. I have now pitched a pack of us-05 in hopes of provoking it further.

I took the first reading on my Bock which used 65% Gambrinus Munich. It went from 1.064 to 1.023; attenuation is 63%. Everything was converted properly in the mash - this was not an issue. This beer was fermented on the same yeast cake as my dunkel. Perhaps it's the yeast that's ****ting out on me? 60% attenuation is very low IMO. I regularly get 70-75 with S-23. I kind of think it's the malt. Is it is possible that Gambrinus Munich just contains too many unfermentable sugars to get proper attenuation. Being a Munich malt - which is typically a base malt - this seems odd to me, but maybe it's possible?

 

[giraffe]

I have never used gambrinus, but ive had trouble with briess and great western, in either fermentability or taste. I use weyermann's munich I and II, or weyermanns floor malt bohemian munich, and both are delicious and ferment out well. I hate shipping things all the way around the world, but its worth the cost to me on that one. I just made a 99% wyrmn bo flr mlt munich dunkel with 833 and got 74% attenuation. ( though the taste is a bit strong, verging on too much melanoidins, next time i may cut with a bit of pils or munich I)