Author Topic: Mash tun dead space  (Read 16562 times)

Offline djakobse

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Mash tun dead space
« on: April 20, 2009, 12:13:21 PM »
I have a mash tun with a rather big dead space below the grate. The problem is that the mash-in amount of water seem to be too small. With the large dead space, there is less water left to mix with the grain. The grain bed seem to be on the dry side.
How can I compensate for this, the program seem to ignore the dead space? Exactly when are the calculations performed, when you enter the mash method, when you move to another field, or what?

Offline MaltLicker

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Re: Mash tun dead space
« Reply #1 on: April 20, 2009, 06:50:29 PM »
There is a setting for the Mash/Lauter tun loss to deadspace in the equipment profile.   My friend fills that first before adding grain and strike water. 


Batch Size: 5.00 gal
 Mash Volume: 10.00 gal
Boil Volume: 7.28 gal
 Mash Tun Weight: 11.00 lb
Evaporation Rate: 12.00 % Mash Tun Specific Heat : 0.120 cal/g-deg C
Boil Time: 60.0  Mash Tun Deadspace: 1.00 gal Top-up for Boiler: 0.00 gal  Equip Hop Utilization: 100.00 %
Losses to Trub/Chiller: 1.20 gal Cooling Loss (%): 4.00
Top up water for Fermenter: 0.00 gal   
Notes: 50L keggle for boiler. 42 qt PolarWare MLT with false bottom. 

Offline djakobse

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Re: Mash tun dead space
« Reply #2 on: April 21, 2009, 12:53:46 AM »
Really so?

I'm aware of the DeadSpace-setting in the Equipment section, but I don't notice any difference when altering it. Which leads me to the second question; when are the calculations performed? Do I have to clear the equipment field in the recipe and reselect it, or are changes reflected immediately?

Offline MaltLicker

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Re: Mash tun dead space
« Reply #3 on: April 21, 2009, 05:50:49 AM »
I just swapped equipment profiles a few times on a single recipe and the sparge water amount changed with each size pot/MLT settings, ranging from 6 gallons to 0.49 gallons.  I believe BSmith loads the equipment profile settings first, as a given starting point, and then calculates the EE% against the selected grains, etc.  The logic being (I think) that these capacities and losses are measurable and largely fixed, so once you know them and account for them, the remaining variability should come from the grist and your process/EE% for each batch. 

Within the equipment profile itself, changing the losses does not interactively change the results.  I believe you'd have to adjust the equipment profile and then select it again in the recipe. 

I ran into a similiar issue when I prepared a recipe to brew outside, hit a snag, and brewed inside instead.  Different pots, water needs, etc., and the water math was entirely different.  Less water, higher SG, so I added water in the boil to dilute. 

Offline BeerSmith

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Re: Mash tun dead space
« Reply #4 on: April 21, 2009, 07:12:42 AM »
Hi,
  There is a copy of the profile in the recipe, so if you make changes to your profile you do need to set it again in the recipe for it to take effect.

Cheers,
Brad
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Offline djakobse

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Re: Mash tun dead space
« Reply #5 on: April 22, 2009, 01:25:28 AM »
I must be doing something wrong.
When I alter the dead space setting from 0.5 litre to 2.6 litres, the water volume for mash-in changes from 12.77 to 12.79 litres. Way to little!
When I'm making changes, I save the profile, selects the profile again in my recipe and saves it.

I also notice that the different mash schemes also have a field for water volume. Will this overrun something?

Offline djakobse

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Re: Mash tun dead space
« Reply #6 on: April 23, 2009, 03:45:43 PM »
I've been experimenting with this a bit now. I make a copy of my equipment and changes only the dead space setting in one of them. Now I have two equipment profiles, one with dead space 0.5 liter and one with 2.5 litres.
In a recipe I select the two profiles alternately and saves the recipe each time.
No change at all.
I do the same again, but also select the mash profile each time.
No change at all.
My conclusion is that the dead space setting has no effect on anything whatsoever!
Please tell me wrong, someone! It's otherwise a great piece of software and I would be very pleased if this was intended to work somehow.

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Re: Mash tun dead space
« Reply #7 on: April 23, 2009, 05:56:23 PM »
Hi,
  The lauter tun deadspace primarily affects the sparge water calculation and not the mash water calculation.  I suppose if you have a large deadspace it should probably be compensated for in the mash in as it will have an effect on your apparent water to grain ratio, but currently this is not done automatically.

Cheers,
Brad
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Offline djakobse

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Re: Mash tun dead space
« Reply #8 on: April 23, 2009, 06:55:44 PM »
OK, see.
I could perhaps adjust the amount of mash water a bit by increasing the water/grain ratio.
But why would the dead space affect sparge water?

Offline MaltLicker

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Re: Mash tun dead space
« Reply #9 on: April 24, 2009, 06:11:27 AM »
The lauter tun deadspace primarily affects the sparge water calculation and not the mash water calculation.  I suppose if you have a large deadspace it should probably be compensated for in the mash in as it will have an effect on your apparent water to grain ratio, but currently this is not done automatically.

That explains my friend's adamant stance that his gallon pre-fill of his MLT was not otherwise accounted for in BSmith.  Most deadspace I've seen is one gallon, which is 2-4 lbs of grain, depending on the water ratio, so I'd say that is important.   Possible to rectify in next release? 
I could perhaps adjust the amount of mash water a bit by increasing the water/grain ratio.
But why would the dead space affect sparge water?

The sparge water calc assumes some ratio of the sparge water will make it through the grains into the wort.  If a gallon is un-retrieveable in the deadspace, than that must be written off as lost and thus more sparge water needed. 

Rather than play with your water ratio to adjust, I'd recommend measuring your deadspace precisely and accounting for that loss offline in your water needs. 

Offline djakobse

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Re: Mash tun dead space
« Reply #10 on: April 24, 2009, 06:34:39 AM »
Or perhaps build myself a RIMS system, so that the mash is constantly sparged with worth....

 

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