Accounting for space under false bottom

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StrontiumDog
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Accounting for space under false bottom

Post by StrontiumDog » Mon May 22, 2017 9:23 am

Howdy everyone.

Just got myself a SS mash tun from Brewbuilder with false bottom and bottom drain, it looks fricking amazing and I can't wait to do my first brew using it.

I have looked around and although there are plenty of posts I can't seem to find a straightforward answer to my question;

How do I account for the space under the false bottom in my mash water calculations? I have 2,230 ml under the false bottom, 360 ml of this is actual dead space.

Is it as simple as doing my total water to grain ratio of 2.5 litres per kg of grain (grain bill of 3.5kg = 8.75 ltrs mash water) then add 2,230 ltrs to account for the space under the FB i.e. 10.98 ltrs (11 ltrs after rounding)?

Or, as I suspect, is it not as simple as that?

I'm trying to learn how to use the Breersmith app but I can only find dead space on there.

Thanks as always

Jase

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Jocky
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Re: Accounting for space under false bottom

Post by Jocky » Mon May 22, 2017 11:17 am

You don't really need to account for the false bottom space, unless you're finding that the mash is too thick. You probably do need to account for the grain absorbing some liquid though - about 1 litre per kg of grain.

Beersmith will take into account your deadspace for the total mash runnings (360 ml), and it will also take into account grain absorption. So it should be telling you to add about 12.6 litres - 8.75 litres you caculated + 3.5 litres to account for grain absorption + 0.36 litres for deadspace.

If you're finding the mash too thick because of the amount of liquid below the false bottom then go up to 3 litres/kg, but I doubt you will need to.
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Haydnexport
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Re: Accounting for space under false bottom

Post by Haydnexport » Mon May 22, 2017 12:35 pm

I add a around 4 liters more that beersmith recommends for the initial mash , but my tun is 80L , what one did you get ? Pictures are always nice 8)

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StrontiumDog
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Re: Accounting for space under false bottom

Post by StrontiumDog » Mon May 22, 2017 4:37 pm

Got the 33ltr one as I don't intend to go larger but will retain value if I do decide to expand. Just need to build my counterflow chiller and get a SS fermenter :-)

Hopefully pictures attached...ImageImageImageImageImage

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Fil
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Re: Accounting for space under false bottom

Post by Fil » Mon May 22, 2017 6:24 pm

to maintain the recipe ideal grain/liquor ratio in the tun simply add the under bottom volume to your initial strike volume, and Since its NOT deadspace then subtract it from your total sparge volume.

however as said above only bother IF your mash seems extra stiff post mashing in..
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Haydnexport
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Re: Accounting for space under false bottom

Post by Haydnexport » Mon May 22, 2017 10:23 pm

What Fil said , i forgot to mention take the extra off the total water.

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Kev888
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Re: Accounting for space under false bottom

Post by Kev888 » Mon May 22, 2017 11:12 pm

Looking very smart indeed!

In traditional mash tuns the difference between the overall mash ratio and the reduction around the grain caused by wort under the false bottom isn't usually profound, and will vary between different systems in any case. So as long as you are consistent in your choice then it will become factored in as part of your own system's volume and efficiency characteristics.

FWIW the difference between total wort and wort immediately around the grain is more exaggerated with full-volume (or near full-volume) systems like the braumeister or BIAB. Here it can be more clearly seen that in almost all cases regarding volume, gravity and efficiency calculations it is the total ratio that is important. There needs to be enough space and wort around the grain to suspend it, but otherwise this is less important provided the wort is stirred or recirculated to even out the sugars and enzymes.
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StrontiumDog
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Re: Accounting for space under false bottom

Post by StrontiumDog » Wed May 24, 2017 8:24 am

Thanks Kev888, really pleased with it all and a massive step up from my previous set up. Just need to get my open university exam out the way so I can get my first brew on with the new kit :-)

My next project will be fitting a temperature controller to the buffalo boiler I have as a HLT so keep an eye out for my next set of posts asking for help with that because I'm naff at electrics as well lmao

As always, thank you everyone for your help.

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