Ss Brewing Technologies Giveaway!

Home Brew Forums > Home Brewing Beer > All Grain & Partial Mash Brewing > Attenuation sucks - must be the mash, but...
Reply
 
LinkBack Thread Tools
Old 04-01-2010, 03:15 PM   #1
Judochop
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2008
Location: Libertyville, IL
Posts: 319
Liked 5 Times on 4 Posts

Default Attenuation sucks - must be the mash, but...

Sorry for the novel. I'm just giving every piece of info I can I think of so I can get some help.

I’m having 2 issues. I guess it’d be nice if one was the cause of the other, so I could fix everything with one fell swoop, but that may not be the case. I’m hoping some brains here can help.

The priority issue is my attenuation. I am ALWAYS stopping 4, 5, 6, even 7 points short of my target gravity. I’m using med-to-high attenuating liquid Wyeast yeasts, using a 1L starter on a stir plate for at least 24 hours, using a pinch of yeast nutrient for the starter, and adding a tsp of nutrient for the boil, using a siphon spray into my primary fermentor, and then shaking the ~5.2 gallons in the 6.5 gallon carboy (so there’s headroom for good splashing) for at least 2-3 minutes.

My grain bills are not particularly heavy on the unfermentables – they are almost always based off of some BYO recipe. Last one I did was a quasi-Guinness close: 7.5 lb Marris Otter, 0.5 lb flaked barley, 0.75 lb roasted barley, 2 oz chocolate. My OG was 1.043, right on target. I used Wyeast’s 1764-Pacman from Rogue (expected to get 72-78% attenuation), fermented perfectly @ 63 degrees with the airlock bubbling solidly for 3-4 days and then slowing down for the 5th, and STILL she’s all tuckered out at 1.016, only 63% attenuation.

Just racked last night and it’s a good beer, but noticeably sweet. I wanted a DRY stout, dang it!

Every beer I do is the same.

  • Yeast count and health is fine.
  • Recipe is fine.
  • Fermentation is fine.
  • Aside from getting an aeration stone, I really don’t think there’s anything more I can do for O2 levels.

So, I’m thinking the problem has to be in my pre-boil processes, right?

Which leads me to issue #2; controlling my mash-out temps.

MY MASH: I heat my strike water and mash in a 10-gallon stainless steel kettle with a false bottom that sits above 1.5 gallons of water. I always aim for strike water 11 degrees above my mash target (which, for the Dry stout, was 150), and after pouring in the grain and stirring a few minutes to break up clumps, my built-in dial thermometer and my handheld probe thermometer both tell me I’m within a degree of target. Happiness abounds.

Q#1: Regarding that 1.5 gallons of water under my false bottom. That’s a pretty heavy chuck of heat down there, which I can’t get to with my spoon when I stir in the grains. Is it possible that my temp readings are only telling me what’s happening at the top and middle of my mash, but nearer that false bottom where the water once was 161 degrees, the mash is really closer to 155 or higher? Does anybody else have a mash-tun like mine (bought from MoreBeer)? Should I be recirculating a few quarts and stirring before I wrap up the mash to let sit?

After mashing 60 min, I (attempt to) MASH OUT. I apply direct heat, and begin recirculating+stirring. I draw off a quart at a time, put it back in pouring it gently over the back of my metal spoon so as not to aerate, and stir the mash to try to disperse the heat. I do this about 5-6 times, watching my built-in dial thermometer. 15 min later or so, the thermometer tells me I’m just about @ 170. I shut off the heat, recirculate once or twice more and start my sparge. 5 minutes into the sparge, my dial thermometer starts wigging out, rapidly climbing higher and higher, soon telling me I’m up to 195! I get angry and call it a liar. About 10 minutes after that, it’s back down to 148, and slowly but steadily dropping down through the 140’s (despite the fact that I’m using sparge water @ about 180 degrees).

So, I’ve just about had it with this mash-out process which seems like it is probably doing more bad than good. Next time I’m going to try to mash out by adding a quantity of boiling water.

Q#2: In calculating how much water I need, BeerSmith asks me how much grain I’ve got and how much water I’ve got. Of course it’s referring to the water I’m using to mash (1.3 q/lb), but should I also consider the 1.5 gallons of water below the false bottom in this calculation? It seems I should since it must have an effect on the total heat present. I’m wondering how much that 1.5 gallons is to blame for many of my issues.

Q#3. Is there a possibility that these wacky temps I’m getting during ‘mash out’ are having an effect on conversion or are otherwise the cause of my miserable attenuation?
__________________
Judochop is offline
 
Reply With Quote Quick reply to this message
Old 04-01-2010, 03:41 PM   #2
Duffer
Feedback Score: 0 reviews
Recipes 
 
Join Date: Mar 2010
Location: Camano Island, WA
Posts: 71
Default

I don't think your mash-out is causing your frustrations, but it may be a clue. By mash-out, your enzymes have already done their work and your starches are already converted as good as they are gonna be for your mash temp. Higher mash-out temps will pull bitterness from the grain hulls but that's about it. (colder mash-out temps may leave behind some sugars are all btw)

BUT.... your "wildly swinging mash-out temps" may be a hint. That instability in temps leads me to believe that your mash temps are either not where you think it is OR it is not even thru the grain bed. ie: it's at 150 where your thermometer is mounted but much higher somewhere else in your grain.

Maybe? That would be my best guess.

Also didn't notice if you have tried different yeasts in your testing?

__________________
Duffer is offline
 
Reply With Quote Quick reply to this message
Old 04-01-2010, 03:53 PM   #3
Judochop
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2008
Location: Libertyville, IL
Posts: 319
Liked 5 Times on 4 Posts

Default

Perhaps my mash temp readings aren't consistent throughout, but if my strike water readings ARE accurate... then my mash temps can't be that far off. If I'm adding room-temp grain to 161 degree water, I HAVE to land somewhere in the low 150's. Still, I do stir the mash for a good minute or two, to try to disperse.

But it's true that I'm not exactly trusting my dial or my digital 6" probe these days. So,
I am going to pick up a long-probe candy thermometer from BedBathBeerandBeyond for this next batch. It'll reach through most of the grain bed, so hopefully that will give me a more accurate reading.

This attenuation thing has GOT to be an issue with the mash though, right? Somehow, some way, it's GOT to be...

__________________
Judochop is offline
 
Reply With Quote Quick reply to this message
Old 04-01-2010, 04:08 PM   #4
Gremlyn
Feedback Score: 0 reviews
Recipes 
 
Join Date: Mar 2009
Location: San Diego, CA
Posts: 2,524
Liked 24 Times on 16 Posts
Likes Given: 5

Default

Do you have a dip tube to get the 1.5 gal below the FB? If not, that's a big problem. You're leaving fermentables behind and probably having to over sparge to compensate.

__________________
Quote:
Originally Posted by Yooper View Post
I'm a fan of "getting it in the can"!
Gremlyn is offline
 
Reply With Quote Quick reply to this message
Old 04-01-2010, 04:21 PM   #5
Duffer
Feedback Score: 0 reviews
Recipes 
 
Join Date: Mar 2010
Location: Camano Island, WA
Posts: 71
Default

[QUOTE=Judochop;1980799]Perhaps my mash temp readings aren't consistent throughout, but if my strike water readings ARE accurate... then my mash temps can't be that far off. If I'm adding room-temp grain to 161 degree water, I HAVE to land somewhere in the low 150's.....QUOTE]

Yes, but, depends on if you are adding grain to water or water to grain and how well it's stirred....

For instance, if you are adding water to grain by pouring the water on top of the grain (how else right?) then the temp of the top grains will be quite high and as the water fliters down thru the grain it will lose heat along the way and get cooler and cooler. The bottom of your grain bed will be really cold. The middle of your grain bed will be about at your target temp, btw. Stirring will be pretty important then as you need to get that hot temp'd grain down to the bottom so it all evens out. As it sits mashing, the temps will equilibrate slowly (grains are a pretty good insulation) but the hottest grains may lose some enzyme power and the coldest grains can't get 'enzyming' until they get warmed up enough and by then the clock has run out for them.

__________________
Duffer is offline
 
Reply With Quote Quick reply to this message
Old 04-01-2010, 04:25 PM   #6
Judochop
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2008
Location: Libertyville, IL
Posts: 319
Liked 5 Times on 4 Posts

Default

Quote:
Originally Posted by Gremlyn1 View Post
Do you have a dip tube to get the 1.5 gal below the FB? If not, that's a big problem. You're leaving fermentables behind and probably having to over sparge to compensate.
No, I don't have a dip tube. But my drain IS below the false bottom still, so I am getting some of that. I figured it out once, and I think it's actually 0.8 gallons which actually rests below the drain. So that's what I'm losing, I believe, as far as yummy fermentables goes.

But as a matter of fact, I already think I have to over-sparge some on smaller beers because my boil kettle is so wide (again, from MoreBeer), by boil off rate is ~25%. If I want a good, 60-min rolling boil, I've got to collect 7 gallons to end up @ 5.25. If I'm only mashing 7-8 lbs of grain, I've got to pump quite a bit of sparge water through to get my 7 gallons.

But hitting OG has never been my problem, and I haven't noticed any astringent flavors in my beers, so I don't think I've been sparging to a point where's it's negatively affected my beer. Then again, maybe my sucky-attenuated, thick-bodied brews are masking the tannins I have been collecting all along.

Am I in need of a better mash tun/narrower brew kettle?
__________________
Judochop is offline
 
Reply With Quote Quick reply to this message
Old 04-01-2010, 04:28 PM   #7
Judochop
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2008
Location: Libertyville, IL
Posts: 319
Liked 5 Times on 4 Posts

Default

[QUOTE=Duffer;1980864]

Quote:
Originally Posted by Judochop View Post
Perhaps my mash temp readings aren't consistent throughout, but if my strike water readings ARE accurate... then my mash temps can't be that far off. If I'm adding room-temp grain to 161 degree water, I HAVE to land somewhere in the low 150's.....QUOTE]
Yes, but, depends on if you are adding grain to water or water to grain and how well it's stirred....
I'm adding grains to water. As I said, I apply direct heat to get my strike water temp 11 degrees above mash target temp, then slowly pour/stir in grains trying real hard to break up any clumps that form. Naturally, I cannot stir the 1.5 gallons of 'foundation' water (water not counted in my grain/water mash ratio) below the false bottom.
__________________
Judochop is offline
 
Reply With Quote Quick reply to this message
Old 04-01-2010, 04:49 PM   #8
Obelisk
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2010
Location: Colorado
Posts: 26
Default

I've just about given up on lower temp fermentation for ales and stay above 65F all the time now - because of the attenuation problem. It also takes longer for the conditioning with the lower attenuation. You might see if you can borrow a max/min temp monitor to make sure you aren't dropping below 63. I moved the temps to the 67-69 range and the attenuation problem went away. What is Wyeast's recommended ferm temp?

__________________
Obelisk is offline
 
Reply With Quote Quick reply to this message
Old 04-01-2010, 05:16 PM   #9
Judochop
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2008
Location: Libertyville, IL
Posts: 319
Liked 5 Times on 4 Posts

Default

Quote:
Originally Posted by Obelisk View Post
I've just about given up on lower temp fermentation for ales and stay above 65F all the time now - because of the attenuation problem. It also takes longer for the conditioning with the lower attenuation. You might see if you can borrow a max/min temp monitor to make sure you aren't dropping below 63. I moved the temps to the 67-69 range and the attenuation problem went away. What is Wyeast's recommended ferm temp?
60-72 degrees for the pacman. (The tape on the carboy read 62-63, so you have to figure it's actually somewhere above that inside there with all that activity). But honestly, this is the coldest fermentation I've done. I'm usually brewing in the summer where I struggle to keep it below 72 degrees. My fermentations finish lickidy-split, but still finish too high. It ain't yeast count, because I've dumped batches directly onto a previous yeast cake, watched fermentation explode, and still stop short of the mark.

Only thing I can figure is that it's in the grain bed, either during the mash, or something during mash-out/sparging. Either that or I'm cursed.
__________________
Judochop is offline
 
Reply With Quote Quick reply to this message
Old 04-01-2010, 05:21 PM   #10
rurounikitsune
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2008
Posts: 101
Liked 2 Times on 2 Posts

Default

try a 90 minute sacc rest. you should see your attentuation improve by a few points.

you might be getting all your starch converted but still have long chain sugars that can be broken down just by letting everything sit a bit longer.

__________________
rurounikitsune is offline
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Controlling Attenuation Through Mash Times BierMuncher All Grain & Partial Mash Brewing 74 08-08-2014 06:39 PM
Mash temp and attenuation Belmont Fermentation & Yeast 1 08-15-2009 01:47 AM
Attenuation and Mash Temperature Question mmb General Techniques 3 10-19-2008 07:50 PM
Help! My Attenuation sucks rcb General Techniques 9 10-12-2008 09:53 PM
Over attenuation and mash time stevecaaster All Grain & Partial Mash Brewing 1 06-06-2008 04:59 PM