Author Topic: Water/grain ratio and water under false bottom  (Read 6874 times)

Offline Hopback

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Water/grain ratio and water under false bottom
« on: September 26, 2010, 01:07:37 PM »
So if you have 10 lb of grain and you're going for 1.25 qt/lb water/grain ratio that's 10 lb * 1.25 qt/lb = 12.5 qt. In my case I have 1 gal under the false bottom of my mash tun so I actually use 16.5 qt to get the 1.25 qt/lb above the false bottom. When calculating strike temperature I have to account for all the water (including what's under the false bottom) and grain that's holding the energy. I heat the water in the mash tun so it doesn't play a part in the energy transfer. I just have to remember not to get freaked out when I see the 1.65 qt/lb water/grain ratio in such a recipe. I wish I could account for the 1 gal under the false bottom in the BeerSmith software, have it take that into concideration, and tell me I have a 1.25 qt/lb water/grain ratio.

ESB and APA being brewed today. First time using BeerSmith. Been using ProMash for years.

Offline MaltLicker

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Re: Water/grain ratio and water under false bottom
« Reply #1 on: September 26, 2010, 08:13:41 PM »
So if you have 10 lb of grain and you're going for 1.25 qt/lb water/grain ratio that's 10 lb * 1.25 qt/lb = 12.5 qt. In my case I have 1 gal under the false bottom of my mash tun so I actually use 16.5 qt to get the 1.25 qt/lb above the false bottom. When calculating strike temperature I have to account for all the water (including what's under the false bottom) and grain that's holding the energy.

I groped with this much too long, and finally decided to adjust my water ratio to account for the dead space under the false bottom.  If I recall correctly, I first used a 1.25 quart/pound ratio, and then backed-into the adjusted ratio needed to keep the total water the same, assuming the gallon under the false bottom.  The logic being that the wort under the false bottom still counts if you can drain it out. 

Offline MmmmBeer

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Re: Water/grain ratio and water under false bottom
« Reply #2 on: September 28, 2010, 07:58:04 PM »
Funny, I just dealt with this issue as well and here's how i solved the problem. Leave you grain water ration as you normally brew. Measure the amount of water under the screen. Enter that value as a negative number in the Lauter Tun Dead Space and beer smith will adust correctly. This is found under your equipment setting. Worked wonders for my 25 gallon batches. There was 2.5 gallons under the screen which left my mash too dry and was having a great impact on my efficiency.

Offline Bonch

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Re: Water/grain ratio and water under false bottom
« Reply #3 on: October 24, 2010, 12:12:24 PM »
It seems to adjust the sparge calculations but not the mash calculations.  Perhaps I am missing something.