Mash thickness question

[andrewb_1985]

So I have done 2 AG brews so far and have had a similar problem both times regarding my mash thickness. My first batch had 20lb of grain at 1.25qt/lb and my second had 16lb grain at 1.5qt/lb. I thought my mash was real thick the first brew but just went with it. My second I couldnt even cover the grain bed. So I increased to 1.75qt/lb. The reason I figure is because I have a 17.5" wide pot and a false bottom 1.5" high. That's a lot of wort under the false bottom. Is there a way in beersmith to account for that space? It seems the false bottom has a big effect on mash thickness. I am planning on cutting the legs down to about 0.75" to help with the problem. Has anyone else come across this?

 

[morticaixavier]

So I have done 2 AG brews so far and have had a similar problem both times regarding my mash thickness. My first batch had 20lb of grain at 1.25qt/lb and my second had 16lb grain at 1.5qt/lb. I thought my mash was real thick the first brew but just went with it. My second I couldnt even cover the grain bed. So I increased to 1.75qt/lb. The reason I figure is because I have a 17.5" wide pot and a false bottom 1.5" high. That's a lot of wort under the false bottom. Is there a way in beersmith to account for that space? It seems the false bottom has a big effect on mash thickness. I am planning on cutting the legs down to about 0.75" to help with the problem. Has anyone else come across this?

I THINK (I do not have a false bottom on my tun) that you can set the deadspace on your equipment profile in beersmith. at least you should account for that. I believe you generally add that volume to your calcs above and beyond the water:grain ratio. that beings said, I generally mash north of 2:1 water to grain.

 

[andrewb_1985]

Yeah I'm starting to see that I like a lower mash thickness ...I do see the dead space option but I thought that was only for losses. As in unrecoverable wort?

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[CadiBrewer]

Yeah I'm starting to see that I like a lower mash thickness ...I do see the dead space option but I thought that was only for losses. As in unrecoverable wort?

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No, the dead space setting is for the amount of wort under the false bottom, whether you can get it out of the tun or not. Measure the amount of water it takes to cover your false bottom in your empty kettle and use this amount. Then when you select your desired mash thickness, you'll get the consistency you are looking for.

 

[andrewb_1985]

No, the dead space setting is for the amount of wort under the false bottom, whether you can get it out of the tun or not. Measure the amount of water it takes to cover your false bottom in your empty kettle and use this amount. Then when you select your desired mash thickness, you'll get the consistency you are looking for.

Ok makes sense, I'm not sure where I confused the definition. How does the dead space affect the mash efficiency or the total efficiency? One would have to compensate with extra strike water and then less sparge water to account for this. I have been falling short of my pre-boil gravities by about 1.008 every time. I had 0.5G as my dead space and have now calculated it as 2.47G. I am assuming less dead space the better?

 

[CadiBrewer]

Ok makes sense, I'm not sure where I confused the definition. How does the dead space affect the mash efficiency or the total efficiency? One would have to compensate with extra strike water and then less sparge water to account for this. I have been falling short of my pre-boil gravities by about 1.008 every time. I had 0.5G as my dead space and have now calculated it as 2.47G. I am assuming less dead space the better?

I'd check your volume again. When I do the math on a 17.5 in. pot, 1.5 inches would be closer to 1.5 gallons. 2.47 seems high to me.

As for your efficiency figures, I'd start dialing that in after you get your mash thickness and volume numbers figured out. Too many variables right now to think your numbers are accurate and repeatable. Lower your efficiency in Beersmith and add more grain until your numbers start to get consistent.

 

[andrewb_1985]

My false bottom is higher than I thought, it's 2.3" tall. What I don't understand is I've hit my target OG both times within 0.001. I'm not really sure how you can achieve your target OG without compensating with dme or water if you fall short of your pre-boil gravity? Any thoughts?

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