Author Topic: Does shape of Tun matter?  (Read 1862 times)

Offline duboman

  • Brewmaster
  • *****
  • Posts: 784
    • View Profile
Does shape of Tun matter?
« on: November 07, 2011, 03:23:24 PM »
I will start by saying I have heard the jokes about a certain cooler color making better beer, that being said we have been using a 5 gal igloo for our mash tun and have no problems meeting our gravities, pre-boil and OG. This weekend we brewed a much larger recipe and required a larger tun so we converted a 12gal cooler to use. We mashed according to schedule and did everything the same as we had been doing previously. The results this time were off quite a bit and the pre-boil gravities fell well short. We wound up adding DME to make up the difference which was really no big deal but my question is this: Does the shape of the cooler make a difference in relationship to the amount of grain, in other words are there certain proportions that should be met to achieve a better efficiency. If the grain bed is too shallow will that make a difference compared to a deeper bed in the way the grain will mash? I know this might sound like a stupid question but I had to ask..............BTW, the 5 gal. is yellow and the 12 gallon is blue..LOL!
Thanks (All water volumes were correct as well as the mash temperatures and the recipe amts were adjusted to correct for past efficiency measurements)
Peace....Love......Beer......

The Commune Brewing Company-Perfecting the craft of beer since 2010

Online morticaixavier

  • Official Poobah of No Life.
  • *
  • Posts: 5670
  • Davis, CA
    • View Profile
    • The Best Artist in the WORLD!!!!!
Re: Does shape of Tun matter?
« Reply #1 on: November 07, 2011, 03:31:09 PM »
I have heard it mentioned that the bed being deeper than is is wide can cause problems but I think those are generally stuck sparges. I do know that efficiency on higher gravity batches tends to be lower. I don't know why this is though.

I find the shape of my coleman extreme is really good for stirring the mash up and I have had problems with efficiency in the past due to not being able to stir well enough.

But major efficiency drops ussually have to do with poor crush of incorrect pH I think. Others will correct me.
"Creativity is the residue of wasted time" - A. Einstein

Jonathan I Fuller

Offline tschmidlin

  • I must live here
  • **********
  • Posts: 8130
  • Redmond, WA
    • View Profile
Re: Does shape of Tun matter?
« Reply #2 on: November 07, 2011, 03:35:51 PM »
Was this fly sparged, batch sparged, or no sparge?  Or something else?  How well does the bigger cooler drain compared to the other one?
Tom Schmidlin

jaybeerman

  • Guest
Re: Does shape of Tun matter?
« Reply #3 on: November 07, 2011, 03:59:02 PM »
Was this fly sparged, batch sparged, or no sparge?  Or something else?  How well does the bigger cooler drain compared to the other one?

+1 (I'd look into differences in lautering time/flow, sparge time/flow/volume, stirring, false bottom)

There is an ideal height to width ratio for mash tuns but relatively speaking you won't experience differences within the homebrew world.  I've brewed on a very wide 20 bbl tun, a square 7 bbl with equal height to width, and a tall 3 bbl tun; IIRC the 20 bbl system itself was radically inefficient but the other two were roughly the same. Are you sure you calc'd your water and grain needs correctly for the 12 gallon system? cheers, j
« Last Edit: November 07, 2011, 04:01:19 PM by jaybeerman »

Offline malzig

  • Brewer
  • ****
  • Posts: 466
    • View Profile
Re: Does shape of Tun matter?
« Reply #4 on: November 07, 2011, 04:35:30 PM »
I do know that efficiency on higher gravity batches tends to be lower. I don't know why this is though.
This is because the amount of wort lost to the grain bed is directly proportional to the amount of grain. 

Assuming complete conversion of the starch in the grain bed, efficiency is then due to lauter efficiency.  For a batch sparge, lauter efficiency is then dictated by volume lost to the grain bed and dead volume, as well as some technical details like stirring the sparge to evenly distribute the sugars in the sparge water.

Fly sparging is more dependent on tun shape and design, primarily because the tun needs to be designed to allow even flow through the grain bed.  That means that the manifold needs to be designed correctly for the shape.  A deeper grain bed will tend to be more efficient for fly sparging because more water will pass through each grain kernel on the way to the outlet, but be essentially irrelevant to batch sparging.

Another potential variable between two tuns is that one might maintain temperature better than the other.  Loss of heat can decrease gelatinization and slow down conversion

Offline duboman

  • Brewmaster
  • *****
  • Posts: 784
    • View Profile
Re: Does shape of Tun matter?
« Reply #5 on: November 07, 2011, 06:33:01 PM »
Thanks for he replies! The rate of flow is the same and this beer was batch sparged as is all or beers. This cooler did lose heat and we thought we did a good job of monitoring and added did have to add 1.25 gallons to bring the heat back up at 40 minutes but we added another 15-20 minutes to the mash thinking we were making up for he loss?

It seems our temperature variables screwed us up a bit!?!
Peace....Love......Beer......

The Commune Brewing Company-Perfecting the craft of beer since 2010

Offline malzig

  • Brewer
  • ****
  • Posts: 466
    • View Profile
Re: Does shape of Tun matter?
« Reply #6 on: November 08, 2011, 04:51:33 AM »
How much different were the efficiencies?  It could be the temperature or it could just be the larger grist size (or another variable entirely, like crush from a different mill).

Offline duboman

  • Brewmaster
  • *****
  • Posts: 784
    • View Profile
Re: Does shape of Tun matter?
« Reply #7 on: November 08, 2011, 06:37:02 AM »
How much different were the efficiencies?  It could be the temperature or it could just be the larger grist size (or another variable entirely, like crush from a different mill).

Our normal efficiency has been in the 75-80% range and this batch came in a paltry 63%. The grain came from our same supplier and crushed with the same, mill that was just calibrated. At this point I will go on the temperature issues as it's getting colder in Chicago and there are quite a few temperature variables we have to play with now unless someone else has something a little more definitive to offer.
Peace....Love......Beer......

The Commune Brewing Company-Perfecting the craft of beer since 2010

Offline weithman5

  • Senior Brewmaster
  • ******
  • Posts: 1668
  • naperville, il
    • View Profile
Re: Does shape of Tun matter?
« Reply #8 on: November 08, 2011, 07:16:45 AM »

This is because the amount of wort lost to the grain bed is directly proportional to the amount of grain. 


this implies the percentage and hence efficiency should be the same.  to lower the efficiency it would be wort lost is proportional to the amount of grain raised to some power. which may be the case. (in other words amount of lost wort increases faster than the amount of grain increases.)
Don AHA member

Offline tomsawyer

  • Senior Brewmaster
  • ******
  • Posts: 1681
    • View Profile
Re: Does shape of Tun matter?
« Reply #9 on: November 08, 2011, 07:23:41 AM »
I'd use a symmetrical tun (cylinder or square over rectangle) for better balance in your beer.  And I've found the optimal height/width ratio of the tun correlates to the OG/IBU, so use those short rectangular tuns for malty brews and the tall water cooler styles for IPAs.

And yes I'm yanking your chains.
« Last Edit: November 08, 2011, 10:09:16 AM by tomsawyer »
Lennie
Hannibal, MO

Offline bluesman

  • Global Moderator
  • I must live here
  • *****
  • Posts: 8678
  • Delaware
    • View Profile
Re: Does shape of Tun matter?
« Reply #10 on: November 08, 2011, 07:43:25 AM »
Could you post your recipe and mash profile including volumes?
Ron Price

Online morticaixavier

  • Official Poobah of No Life.
  • *
  • Posts: 5670
  • Davis, CA
    • View Profile
    • The Best Artist in the WORLD!!!!!
Re: Does shape of Tun matter?
« Reply #11 on: November 08, 2011, 08:45:57 AM »
If you had to add 1.25 gallons of water to get your temp back up but you ran off the same amount of wort as you would otherwise then there was 1.25 gallons of lost wort left in the grain I would think. Don't have the brain power this early in the morning to do the math but that might account for some efficiency loss (well gravity loss at any rate) don't know if it's enough to account for 12 percent though.
"Creativity is the residue of wasted time" - A. Einstein

Jonathan I Fuller

Offline davidgzach

  • Senior Brewmaster
  • ******
  • Posts: 1498
    • View Profile
Re: Does shape of Tun matter?
« Reply #12 on: November 08, 2011, 10:26:41 AM »
Including the questions from above, I have a few.  What did you use as a manifold/false bottom?  What were the mash temps?  
Changing the brewery means you also need to get used to your new equipment.  Was anything different in the build?  IMHO, I think the temperature change is the culprit here.
Dave Zach

Offline malzig

  • Brewer
  • ****
  • Posts: 466
    • View Profile
Re: Does shape of Tun matter?
« Reply #13 on: November 08, 2011, 10:39:07 AM »

This is because the amount of wort lost to the grain bed is directly proportional to the amount of grain. 


this implies the percentage and hence efficiency should be the same.  to lower the efficiency it would be wort lost is proportional to the amount of grain raised to some power. which may be the case. (in other words amount of lost wort increases faster than the amount of grain increases.)
I see where you're coming from, but you're making it more complicated than it is.  Essentially, for a 10# batch you lose 1.2 gallons to the grain bed, or 16% to hit 6.5 gallon pre-boil.  For a 20# batch, you lose 2.4 gallons, or 27%, to the grainbed. So, the amount lost increases faster than the total volume increases, but the amount lost is proportional the the grist weight.

Offline malzig

  • Brewer
  • ****
  • Posts: 466
    • View Profile
Re: Does shape of Tun matter?
« Reply #14 on: November 08, 2011, 10:43:50 AM »
How much different were the efficiencies?  It could be the temperature or it could just be the larger grist size (or another variable entirely, like crush from a different mill).

Our normal efficiency has been in the 75-80% range and this batch came in a paltry 63%. The grain came from our same supplier and crushed with the same, mill that was just calibrated.
Almost forgot to ask? What were the two grist weights?