Width of Lauter tun

[brothersbrewing]

I am in the process of building out a 10bbl brewhouse and am trying to determine the ideal grain bed depth so I know what size to make my MLT.

I feel that a target original gravity of 17 plato should net roughly a 7.6% alcohol beer. It’s a good number to shoot for because I will probably do some 5% beers and maybe a 9 or 10% if needed.

I have a beginning malt bill to make that happen of about 950 lbs. At that malt bill, we will shoot for a 24” grain bed by calculating the volume of mash. Can anyone confirm if I am on the right track or not?

If anyone could provide some input I'd really appreciate it.

Thanks!

Mike S.

[Ray Hodge]

It seems that 950# is more than you need to get 17P at 10 bbls, but aside from that the bed depth recommeded to me by Specific was 16.7" to setup a preferred loading of 34.82#/ft2, based on a grist charge of 50#/bbl for a 12.5P beer. With this data as a baseline:
radius of mash tun=sqrt (50#/bbl X system size(bbls)/34.82 lbs/ft2) X 12". If this does not make so much sense I can scan the calc sheet they gave me and forward it to you. PM me your e-mail. hope this helps.

[NHBrewer23]

Lauter Tun Dimensions

I spent a lot of time on this very topic this past summer when I was working on designing our mash/lauter tun. As stated, Specific Mechanical assumes 90% efficiency with an average 12 plato beer.

After comparing several of the popular brewhouse manufacturers specifications, I feel that I have developed a spreadsheet that helps with sizing the mash/lauter tun.

Within the link that I have provided, you will find an excel spreadsheet named, "Henniker Brewing Brewhouse Volumes." Within this spreadsheet, the fields on the first sheet that are highlighted require user input. The spreadsheet calculates the kettle full volume and mash/sparge volumes based upon a desired BBT volume and assumes various loss that can be adjusted.

When you determine the plato of your average beer, enter that value in cell B50. From there, a weight of grain will be calculated based upon a 90% efficiency. On sheet two, the mash tun diameter will be calculated based upon 170kg/m^2 loading. The mash tun height is calculated based upon the highest plato beer that you wish to produce and still have a full collection.

Play with the spreadsheet and let me know if you have any questions or concerns. Here is the link: https://docs.google.com/folder/d/0B-...RScGRUZ0E/edit

James

[brothersbrewing]

Awesome info guys. What a great resource!
Mike

[dancook]

On sheet two, the mash tun diameter will be calculated based upon 170kg/m^2 loading.

OK, dumb question of the day: is recommended bed loading, for example 170 kg/m2, based on the weight of the dry grain and not the hydrated grain? My recent post made an assumption that bed load involves hydrated grain, but NHBrewer23's "Henniker Brewing" spreadsheet appears to depend only on the weight of the dry grain. I am basing this conclusion on the equations which calculate the cells called Average Grain Weight, False Bottom Area, and Mash Tun Diameter on sheet two (aka "Mash Tun dimensions").

[dick murton]

If you look at the cell b7 on MT dimensions, it tells you it is copied from B29 on the brewhouse volumes sheet.

[dancook]

If you look at the cell b7 on MT dimensions, it tells you it is copied from B29 on the brewhouse volumes sheet.

Sorry, I was not clear. I do see that the Excel spreadsheet calculates bed load based only on the weight of the dry grain. But my question was: is that the *traditional* way to calculate bed load?

[NHBrewer23]

Grain Bed Depth

Hi Guys! I apologize for not responding as I was not aware there were questions about the spreadsheet. I have updated the spreadsheet recently and have added a grain bed depth calculation. Let me just give you a quick run down on how I calculate grain bed depth...

Assumed density of wet grain is approximately 25 lbs/cu. ft.
With the preferred bed loading of 170 kg/m^2 the false bottom area is calculated based upon your anticipated "Dry" grain weight. In the spreadsheet, this is cell B9.

Step 1-Divide this value by 144 to covert the false bottom area into Sq. Ft.
Step 2-Now divide your "Dry" grain weight by the value in Step 1.
Step 3-Divide the value from Step 2 by the density of wet grain (25 lbs/cu.ft).
Step 4-Multiply the value from Step 3 by 12. This will give you your anticipated wet grain bed depth.

For Example:

15 BBL batch using 910 pounds of "Dry" grain.
Typical false bottom area: 3,763 sq. in.

Step 1: 3,763 / 144= 26.13 Sq. Ft.
Step 2: 910 / 26.13= 34.83 Lbs/ Sq. Ft
Step 3: 34.83 / 25= 1.39 Ft.
Step 4: 1.39 x 12= 16.72"

I intentionally left out units to make the example easier to follow within a forum.

I hope this helps.

[dancook]

With the preferred bed loading of 170 kg/m^2 the false bottom area is calculated based upon your anticipated "Dry" grain weight.

I am not clear on why bed load is based on *dry* grain weight rather than wet grain weight. After all, the weight of the combined [grain + mash water] is resting on the false bottom (except for any water in the dead space below the false bottom). With a grain bill of 800 pounds and with 300 gallons of strike water, a false bottom with a diameter of 65" would experience a load of approx 700 kg/m^2 when water is involved in the calc, but only 165 kg/m^2 if we include only the dry grain in the calc.

Obviously the 2nd number (165) is a lot more in line with recommended bed loads. So I'll use the principle of Occam's Razor to conclude, based on the fact that 15bbl tuns are commonly produced with a diameter in the neighborhood of 65", that it is only the dry grain weight which matters for computing bed load. The alternative conclusion, i.e. that everybody is putting 4x the recommended load on their false bottom, seems unlikely.

[dick murton]

It works - using the mash or wet grains mass doesn't. It is standard practice because you may vary the amount of water added to the grist during mashing in. The water part does not restrict the flow. The grain part does. There are also variations on effective volume according to the type of material used in the mash. I can't remember the figures, but for instance, because maize has much less residual material after all the starch has been converted, you can add perhaps twice the weight of maize than you can barley for a given volume of spent grains. This calculation is more applicable to mash filters, but can be applied to lauters. For instance they use up to 30 % maize or rice in some brews in India, which allows them to produce mover volume and or higher gravity beers than if they used all malt grists.

[dancook]

...standard practice because you may vary the amount of water added to the grist during mashing in. The water part does not restrict the flow. The grain part does.

OK, that makes sense. Thanks for the explanation Dick!

[Eduardopage]

Hi James,
I read your post and thought to ask you to comment on your mash/launter desing. Is it working as expected?
I am designing a 1500 liter brewhouse and don't have much experience on the subject and would really appretiate your opinion. Could you give me some pointers regarding mash/launter tun design?

I spent a lot of time on this very topic this past summer when I was working on designing our mash/lauter tun. As stated, Specific Mechanical assumes 90% efficiency with an average 12 plato beer.

After comparing several of the popular brewhouse manufacturers specifications, I feel that I have developed a spreadsheet that helps with sizing the mash/lauter tun.

Within the link that I have provided, you will find an excel spreadsheet named, "Henniker Brewing Brewhouse Volumes." Within this spreadsheet, the fields on the first sheet that are highlighted require user input. The spreadsheet calculates the kettle full volume and mash/sparge volumes based upon a desired BBT volume and assumes various loss that can be adjusted.

When you determine the plato of your average beer, enter that value in cell B50. From there, a weight of grain will be calculated based upon a 90% efficiency. On sheet two, the mash tun diameter will be calculated based upon 170kg/m^2 loading. The mash tun height is calculated based upon the highest plato beer that you wish to produce and still have a full collection.

Play with the spreadsheet and let me know if you have any questions or concerns. Here is the link: https://docs.google.com/folder/d/0B-...RScGRUZ0E/edit

James

[dick murton]

I realise this is a fairly old post, but I have only just got around to looking at this, as much as anything to compare with my own calculations. Please would you explain why the value in the Brewhouse Volumes, line 37 have been chosen. Because the value loaded in the copy I downloaded shows 23.11 bbl in cell B37, as this has been manually input, I wondered why this apparent strange value has been used - there doesn't appear to be any correlation to any other figure. And of course, this value is used in the MT floor loading calculations sheet. And why choose 17 Plato?

Why not simply leave these fields out and perhaps use maximum and minimum loadings in the calculations?

Thanks for any explanation

[NHBrewer23]

Hi Dick,

I'm lucky to have seen this post as I don't receive notifications. I haven't touched this spreadsheet in a few years. Cell 37 is a place holder. What I did was ran a seperate calculation based on the highest plato beer I was looking to brew with a full kettle collection volume. I used this cell to merely store what the maximum volume of the mash tun would need to be in order to accommodate the grain volume for the largest batch.

I used 17 Plato to base the mash tun size off of because one of our flagship beers was going to be 17 Plato.

I love the feedback and the fact that this thread is still kicking around.

Cheers,

James

[dick murton]

Thanks James

I did wonder if this was why they were in, but thought maybe I had missed something really obvious.

Cheers