Deadspace/Mash Question

[Wallachia]

Hello all,
Plodding along, made a BIAB that was pretty damn good. I was thinking of going with a batch sparge for my next batch but I am curious about a potential problem with my equipment.

I have a 10-gallon kettle with a false bottom and a mesh screen spigot at the bottom. The issue is that the false bottom creates a 2 gallon (!) deadspace.

My boiloff is about 1gal/hour and I'm making a 5-gallon batch, so I'll somehow need to mash with enough water to cover the 2 gallon dead space and the grain bed, but if I batch sparge after conversion (again, with enough water to incorporate the grainbed, won't I end up with way too much wort (on the order of 2 gallons too much)? Maybe I'm overthinking this?

 

[OleBrewing]

Are you considering any grain absorbtion?

 

[GrogNerd]

you only have to consider the deadspace and grain absorption in your calculations for strike water, not sparge water

after you collect your first runnings, you should sparge with just enough water to get you to your pre-boil volume.

 

[lhommedieu]

Hello all,
Plodding along, made a BIAB that was pretty damn good. I was thinking of going with a batch sparge for my next batch but I am curious about a potential problem with my equipment.

I have a 10-gallon kettle with a false bottom and a mesh screen spigot at the bottom. The issue is that the false bottom creates a 2 gallon (!) deadspace.

My boiloff is about 1gal/hour and I'm making a 5-gallon batch, so I'll somehow need to mash with enough water to cover the 2 gallon dead space and the grain bed, but if I batch sparge after conversion (again, with enough water to incorporate the grainbed, won't I end up with way too much wort (on the order of 2 gallons too much)? Maybe I'm overthinking this?

2 gallons of deadspace seems excessive. Could you provide a picture of your mash tun? To measure deadspace, pour a measured amount of water into your empty tun (e.g. two gallons). Run it off and measure this amount; the remainder is your deadspace (i.e., what remains under your false bottom and spigot). If you actually DO have 2 gallons of deadspace, then I'd consider getting a new mash tun.

 

[Brauer]

You could always install a pick up tube. That would make your dead nonexistent.

 

[GrogNerd]

I should have mentioned that too. 2 gallons is way too much potential beer to be wasting

 

[Wallachia]

2 gallons of deadspace seems excessive. Could you provide a picture of your mash tun? To measure deadspace, pour a measured amount of water into your empty tun (e.g. two gallons). Run it off and measure this amount; the remainder is your deadspace (i.e., what remains under your false bottom and spigot). If you actually DO have 2 gallons of deadspace, then I'd consider getting a new mash tun.

It's a Bayou kettle. Not a cooler or anything nearly so insulated, but I had good results with old-blanket-based insulation

I think perhaps I'm confusing my terminology here. The 'deadspace' in the kettle (the amount of liquid left over when I drain it) is something like a quarter gallon or so. What I meant to refer to before is that 2 gallons is the amount of liquid between the bottom of the kettle and the false bottom

 

[Wallachia]

Are you considering any grain absorbtion?

It's going to be about 1.6 gallons with my grain bill.

I've figured out most of that stuff in BeerSmith, i'm mostly concerned about the really-high false bottom that comes with this kettle lifting the grain bed too high, and having some portion of it "sticking up above" the mash water, which would obviously be a very bad thing for mashing in general

 

[OleBrewing]

Sounds like your false bottom sits way too high. Does the false bottom use legs that keep it off the bottom? A picture of your false bottom will give you some quick answers or solutions.

 

[doug293cz]

I use a Bayou Classic kettle with a steamer basket, and have the same issue with "dead" space below the bag. Rather than batch sparge, I do a pour over sparge with the bag suspended above the BK. I suspend the basket with a pulley dropped from the top of an 8' step ladder. The most sparge water I ever used was 2.5 gal, and usually use less. Not sure that would be enough for a proper batch sparge for 10 - 15lbs of grain.

Brew on

 

[augiedoggy]

Sounds like your false bottom sits way too high. Does the false bottom use legs that keep it off the bottom? A picture of your false bottom will give you some quick answers or solutions.

I also use a bayou classic kettle... theres almost 3 gallons of space under the false bottom however its not "dead space since I use a bazooka tub which is dropped to the base of the pot and only leaves about 1/2 gallon or so of liquid in the kettle if I were to do a full drain... the confusing part is the effect this has on the amount of strike water is used because of mash thickness being effected.... I add 2 gallons to my batches and subtract this from the amount of sparge water I use...
I also recirculate my mash so its not an issue like it could be for someone who doesnt not recirculate during mashing..

 

[loudrail]

The problem could be that if you use 1.5 qts/lb of grain will may have more water under your false bottom than what is in contact with your grain.

 

[McKnuckle]

...the confusing part is the effect this has on the amount of strike water that is used because of mash thickness being affected....

I recently got a 44 qt Bayou kettle with the same basket, but I haven't brewed with it yet. I plan to BIAB (natch), which means I'll have a full volume mash anyway, but the amount of water touching the grain will be less due to the dead space below the basket. I figured this would be fine, because sugars would have a nice "clean" space to dissolve into.

However, I didn't think about calcuating strike temp... how do you do it? Do you consider the full volume of water, or just the volume from the bottom of the basket on up? Any anecdotal experience would be great for how it turns out in practice.

 

[stpug]

A PITA, but I've helped a friend with a similar situation. We mashed without the falsebottom. At the end of mash, dumped mash into bucket, installed falsebottom in pot, poured mash back into pot. It worked out fine, just a little extra muscle. I would aim to keep the turbulation to a minimum for oxidative reasons, but otherwise it was okay. A longer-term solution is preferable.

 

[doug293cz]

I recently got a 44 qt Bayou kettle with the same basket, but I haven't brewed with it yet. I plan to BIAB (natch), which means I'll have a full volume mash anyway, but the amount of water touching the grain will be less due to the dead space below the basket. I figured this would be fine, because sugars would have a nice "clean" space to dissolve into.

However, I didn't think about calcuating strike temp... how do you do it? Do you consider the full volume of water, or just the volume from the bottom of the basket on up? Any anecdotal experience would be great for how it turns out in practice.

Yes, you calculate strike temp using the total volume of water in the kettle. If you don't, your mash temps will come out too high because of the extra heat supplied by the water below the basket.

Brew on