Recoverable mash deadspace and cooler/false-bottom mash tun questions

ColoradoChuck

ColoradoChuck

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The built-in equipment profiles all have 0 gal for the mash tun's recoverable mash dead space (RMD). When I add water to my Igloo, it takes about 58 oz of water to submerge the entire dome (Titan from Northern Brewer). The tap is above the top of the dome. Not sure if that matters to calculating the RMD.

Questions:

Is the fact the tap is above the dome the reason the RMD is 0 gal?
How does one perform a measurement of the RMD on a cooler/false bottom tun?
What does the RMD do in BS3? Is it the minimal volume that keeps the grain wet--before adding mash/sparge water? Something else?

Many thanks!
 
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The built in equipment profiles should only be taken as a starting point for you to build your own, more precise equipment profile. You really need to make your own volume measurements. This tutorial does not use a cooler system but the concepts are the same. Take accurate measurements of how much water goes in and accurate measurements of what comes out.

Another tutorial that I have used with success is this one from Marshall Schott at Brulosophy:
 
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I've looked at both videos, Kevin, and thank you for linking them.

As neither of these tutorials deal with cooler/false-bottom configuration, and the new BS3 interface (v3 adds this new RMD parameter to the profile), I remain unclear about how specifically I assign the recoverable parameter: what do I measure--volume from what to what? What configuration of hardware (height/volume space under the dome, position of the tap, etc). I get how to measure "unrecoverable" volume; it's the RMD for the false-bottom case that is eluding my understanding.

I try to be very careful with measurement and use this pitcher (from Amazon). It's marked with 2 oz graduations, and is pretty sturdy:

1736381509812.png
 
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Some systems have recoverable space and some don't. It is mainly a function of the drain placement and the mash filter placement. If the drain is designed to recapture everything below the mash filter, then the volume below the filter is all recoverable. However many systems leave some volume of wort in the bottom of the mash tun after you are done - that would be a non-recoverable (dead spave) volume.
 
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When measuring your liquid volumes do so by weight and not by markings on a container.
 
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Brad, Kevin please correct or comment on this hypothetical as needed.

I'm assuming the two tun adjustment parameters (unrecoverable and recoverable) deal with volumes below the filter. The filters are flat.
1736439453064.png
If I fill up to the filter (vol1 + vol2), that's the volume under the filter. I drain at the tap until no water exits the tap, and that volume is the recoverable mash deadspace (vol 1). I now pick up the vessel and dump what's left (vol 2); that's the unrecoverable deadspace. I assume BS3 will add vol1 and vol2 to the needed total volume added to the desired volume above the filter to do the mask, and will subtract out vol2 from what is transferred to the next stage (fermenter, another container, etc).

Now I have a rig with the tap very close to the filter:
1736440785679.png
I fill water to the filter (vol4), which is clearly unrecoverable. But since the tap is almost at the filter level (actually a little above the top of the dome, but the dip tube at the elbow is just below the dome), vol3 is zero.

The assumption here is that the filter is flat. A domed false bottom can be covered up to the top of dome, but most of the water is not "below" the filter. Flat or domed, the unrecoverable loss is easy: add water until it starts coming out of the tap, or fill above the tap, then empty via the tap, and measure what's left. For the recoverable amount, what does "above" or "below" the filter mean to a domed filter? It's just this small detail that's getting me stuck.

I'm not stressing (Denny), just dwelling a bit too much (probably).
 
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Do you have a pick up tube? That changes your diagram. The best way however is to just make the darn measurements on your system.
 
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Not exactly a pickup; it's just an elbow on the dome with the ingress a half inch or so below the top of the dome, and half inch above the bottom of the cooler. It drains until it breaks siphon. Standard domed false bottom setup. But very "low" to the cooler bottom, and very efficient (only 14 oz remains unrecoverable).
1736529385103.png
(from brewhardware.com)

I do measure the unrecoverable loss directly, as described two posts above. The volume under the false bottom (but is recoverable) is my head scratcher. Another post by kw642, https://beersmith.com/forum/index.php?threads/how-can-i-improve-this.20659/post-73746, discusses his numbers. He mentions "1.75 gallons (6.62L) from the screen to the bottom". If you use parabolic false bottom, is that volume beneath the apex of the false bottom? If so, a lot of that water is actually above the false bottom--not below the entire screen! Volume beneath a screen only makes sense for a flat filter.

The equipment wizard help says, "Mash Tun Addition to Compensate for Recoverable Volume Under the Filter Screen". Since for me, no volume remains recoverable when all liquid is below the entire dome, I'm just setting non-recoverable to 0.1gal, recoverable to 0, and calling it a day.

Thanks again.
 
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I'm new to the game, but this is how I thought of it. If you have a modern, all-in-one system, you likely have a malt pipe or grain basket. The grain goes in the basket but the water goes in the basket and all around it. The water that's not in the basket is the dead space. Of that dead space, there's the recoverable part which is the part that you can drain from the tank. And the unrecoverable part, which is the part you can't.

Since you are using a false bottom, I don't think you have any recoverable dead space. And likely have very little unrecoverable since that elbow/siphon should get most of the wort out.
 
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