2 Gallons of Water Below False Bottom - Opinion on Mash Water Amounts

Guys, this is driving me nuts. I just got a brew stand and built my keggles and am getting ready to do my first beer since significantly upgrading my equipment.

In my mash tun, I have a valve and a false bottom. The false bottom sits above the valve and therefore 2 gallons of water sit below it.

My concern is with mashing. I brew 5 gallon batches. If I am supposed to mash a recipe with 12 lbs of grain at 1.33 qts per lb, I would be using 4 gallons of water. My issue is that 2 gallons of that are UNDER my false bottom and not in contact with the grain.

I plan to recirculate my mash using a pump to maintain my temps.

Isnt my concern about the water not being in contact with the grain legit? Am i missing something? What do you think? What do you recommend? If this is an issue, i dont want to add 2 gallons of water to the mash to make up for this or I will end up needing to boil a ton off in the kettle so that I want to avoid.

2 gallons seems like a lot. However if you are recirculating it's not an issue as you are constantly flowing wort through the grains. By the end of the process with a properly placed dip tube you should leave less than a cup of wort behind, in addition to losses in the lines & pump.

My concern is that basically half of the grain will not be in the water at all. If i recirc, the top half of the grain will not stay / get wet.

Keep the thoughts and opinions coming.

How high up is the false bottom? You could enter the mash tun 'dead space' into BeerSmith and have it offset that for your mash volumes.

I just checked the preset keggle mash tun hardware profile in BeerSmith... You should only have 1 gallon of deadspace in the mash tun (at most)...

I'm getting ready to get a 1/2 bbl keg converted into a mash tun. I also plan to recirculate during the mash, so that I can direct fire it. I do plan to make sure the false bottom is set at a decent height, so that I get enough clear wort to circulate, and don't lose too much water in contact with grain during the mash.

Maybe you should try changing the false bottom for one that has less deadspace. How is the bottom setup? I'm talking about the ball valve relative to the false bottom...

The ball valve is as low as it can be.. there is a pickup tube reaching down to grab the rest. The false bottom is the same size as the interior of the keg (15 gallon standard keg) in diameter and therefore sits exactly on top of the valve.

Sounds like it's setup as best as possible... Just curious as to why you have 2 gallons under it... Just curious, but what did you use to measure the water that's under the false bottom? How far from the inside bottom is the ball valve? I know my Blichmann kettle has it's ball valve higher up the side than I have the valve in the aluminum kettle I setup.

Did you set this up yourself or did someone else?

i drilled the hole for the valve but then hated my weldless fittings and had them welded. To measure it, i took gallon increments of water and began to pour it in.. it was damn near 2 gallons of water under the FB.

He made the FB as well and is a main guy in our Homebrew club. He also built my brewstand and many other members stands.

How far up, from the start of where the keg is the same diameter, is the center of the valve? For example, in my converted aluminum pot kettle, the center of the hole is 1.5" from the outside bottom. In the Blickmann, it's 3" from the bottom (outside)... Shouldn't be much different measuring from the inside (the aluminum is 4mm thick, the Blichmann is thinner)...

I went weldless on the kettle I made. It took a bit of figuring out, but I got it to seal up nice without too much effort/time.

I plan on having threaded fittings welded to the keggle/mash tun so that I can change the valves, and/or plug them later (removing the valves)... I want flexibility, but also to not need to worry about an O-ring failing on me. I've not had that happen so far, but I'd rather have it a non-issue.

Why don't you put the FB under the valve and drill a hole in it for your dip tube to go through? That's how I set mine up and it only takes 7/8ths of a gallon to hit the bottom of the FB. What is holding your FB up so high other than the bulkhead coupling?

Nothing other than the bulkhead is raising it. Maybe i need to re-measure, but im pretty sure it was 2 gallons.

i see what you are saying there bobby. The only thing stopping me from doing that is that I have a burlap grain bag with a mesh for the bottom (of the bag) which is custom made to sit on top of the false bottom in its current position. It then reaches up to sit on the top of the keggle opening for stability. Do i HAVE to use the bag? nah.. not at all... but i really do want to keep it to help keep my wort as grain free as possible and it will make it easy to clean the mash tun.

A possible solution:

What do you think the repercussions would be if I mashed with the 2 extra gallons and sparged with 2 less? The only thing that sucks is that i will have to fly sparge or that 2 gallons will once again wreak havoc. Would my efficiency suffer greatly?

You'll thin out your mash with the extra 2 gallons, changing the characteristics of the wort. Not that it's necessarily bad.

This might be a pain it the ass when it comes time for cleaning, but how about getting some stainless bars cut to take up the space below the FB? Displace some of that 2 gallons, and raise the water level. Just about any scraps of SS will work, if you can find someone who has a scrap bin (AKA the dude who built your stand.) You'llhave to clean them every time, which might be as easy as leaving them in when you fill your MT with oxyclean/PBW.

B