Author Topic: Mash water volume & deadspace  (Read 4627 times)

Offline spademan

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Mash water volume & deadspace
« on: February 04, 2012, 06:57:22 AM »
I am using BS 2.0.57

On my 15 litre Stammtisch mash tun I intend using a 2.6L grist ratio.
A total grain bill of 2.197K therefore requires 5.71 L mash water, but I have a mash tun deadspace of 1.39L.
The mash-in step window in the BS recipe design factors in both volumes to come up with a mash water volume of 7.12L. That changes the ratio to 3.2.

Given the change in the grist ratio would to some degree affect the enzymatic action of a 60 minute mash is it better to add the deadspace volume to the sparge volume so as not to alter the original grist ratio.
« Last Edit: February 04, 2012, 07:00:43 AM by spademan »

Offline spademan

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Re: Mash water volume & deadspace
« Reply #1 on: February 08, 2012, 04:59:24 AM »
Does anyone have some thoughts on this, as it does seem important to outcomes. I will be batch sparging.

Thanks

Offline jomebrew

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Re: Mash water volume & deadspace
« Reply #2 on: February 08, 2012, 09:11:13 AM »
If you are simply trying to get beersmith to say what you want it to say, you can tweak the deadspace or geometry of the mashtun to achieve the number you are seeking.   It does not seem to matter because you are seeking a 2.3l:1kilo water to grain ratio.

Personally, I would ignore the beersmith numbers if it is too hard to make it say what you are wanting it to.   I would simply do the math myself.  In many cases, I use my own simple web or android tools because they are simple and good enough to get me in the ball park.  Honestly, if I am supposed to ad 23.75 liters of strike water, I am somewhere in the vicinity but not so concerned if it is  23.5 or 24.25. 

Offline paradisecreekbrewery

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Re: Mash water volume & deadspace
« Reply #3 on: February 08, 2012, 11:22:19 AM »
The grist ratio has to do with the amount of water in direct contact with, and surrounding the grains. The enzymatic reactions occur on the grain kernel not in the deadspace area. The deadspace addition is to let you know how much water to add altogether so your grist ratio, that which is actually in direct contact with your grains, is correct.

Offline jomebrew

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Re: Mash water volume & deadspace
« Reply #4 on: February 08, 2012, 12:31:48 PM »
The grist ratio has to do with the amount of water in direct contact with, and surrounding the grains. The enzymatic reactions occur on the grain kernel not in the deadspace area. The deadspace addition is to let you know how much water to add altogether so your grist ratio, that which is actually in direct contact with your grains, is correct.

I believe there is ample enzymatic activity in the dead space.  But as you say, the dead space value is needed to ensure the water to grain ratio, for the water in close contact with the grain, stays in the range you are setting.  So, you need to fill the dead space before adding the calculated water based on the ratio configuration. 

Beersmith should calculate the amount of water based on the grist ration then add the dead space value, which is does as described in the original post.  The enzymatic process is not affected much because the water in close contact with the grain maintains the ratio.   The enzymatic processes also occurring in the dead space so it is not simply diluting the wort headed for the kettle.   

In the end, the wort in the kettle should achieve the desired pre-boil gravity assuming the efficiency of the process also matched the anticipated value.