Extraction Column Design for Mash

[Hops-a-Lot]

I have been doing some thinking lately about alternative equipment set-up (mostly due to space constraints) and one that I have on my mind currently is the use of an extraction column for mashing. I have some basic design ideas and plan to build a pilot system this year to test the program, but I was wondering if anyone on here had ever messed around with the concept before.

I would be using an insulated PVC pipe held vertically and fed from the bottom up at a flowrate adequate enough to maintain fluidization of the grain bed. There would be enough head space to avoid clogging the outlet. The feed would be from a HLT held at the desired mash temp and the output of the column would be run back to the HLT and recycled into the column in a closed-loop configuration. I am thinking that by recirculating back to the HLT (which is held at a constant mash temp, or adjusted for step mashing) and running back through the column you could significantly improve overall yield and reduce energy requirements.

For a five gallon batch using the mash rules of thumb as outlined by Papazian:

• Grain and Adjunct (lbs): 10
• Mash Water (gal): 2.5
• Water Absorbed by Grain (gal): 1
• Sparge Water @ 170F (gal): 5
• Water Added to Boil (gal): 0
• Water Evaporated During Boil (gal): 1
• Yield to Primary (gal): 5.5
• Yield to Secondary (gal): 5

This would make for an overall water requirement of 2.5 + 5 = 7.5 gallons. Could you monitor the completion of the overall mash by taking SG reading at the recirculation tank (adjusting for dilution)? I am not sure if this has any merit and I am excited to give it a go to see what happens. It is my hope that my mash times can be lowered and my overall yield improved. I look forward to the discussion.

 

[mnadamn]

IMHO this is an intresting idea, but I see 2 problems with it:

I would think that by using a column you would lose efficiency because you are not going to be running all of the water through all of the grain. You will find that you are pulling most of the water directly from the top as that will be the path of least resistance.

This setup also might not increase the flow rate too much either as the total open surface area will be far less significant than that of a false bottom.

 

[Bobby_M]

Just so I'm sure what you're proposing. You want a tall column of mash where you recirculate the entire time by underletting the bed with pumped liquid mash and taking it off the top. If so, how are you going to keep grain from exiting the tube up top? You said you'd have enough headspace, but with the mash being that fluid, you will get grain. Maybe a mesh on the outlet?

With that out of the way, you've listed a 1qt/lb mash ratio which is WAY too thick for recirculation. That ratio is pretty thick when all of the liquid is IN the mashtun. You're talking about having some tied up in tubing and enough in the HLT to apply heat. You'd need at least 2qt/lb for that.

If you're heating your mash via the HLT, are you talking about through a heat exchange coil? If not, where will you heat your sparge water?

Last.... I wouldn't mash in PVC.

 

[Hops-a-Lot]

Just so I'm sure what you're proposing. You want a tall column of mash where you recirculate the entire time by underletting the bed with pumped liquid mash and taking it off the top. If so, how are you going to keep grain from exiting the tube up top? You said you'd have enough headspace, but with the mash being that fluid, you will get grain. Maybe a mesh on the outlet?

I think that a mesh at the top of the column or a large guage filter at the outlet would be a nice addition. You could also vary the flowrate of the liquor to ensure that you are getting enough force to fluidize the bed without pushing the grains up to the top. It would be a balancing act for sure.

With that out of the way, you've listed a 1qt/lb mash ratio which is WAY too thick for recirculation. That ratio is pretty thick when all of the liquid is IN the mashtun. You're talking about having some tied up in tubing and enough in the HLT to apply heat. You'd need at least 2qt/lb for that.

Great addition. I am pretty new to brewing in general and I tend to get ahead of myself with ideas without thinking them through completely. It would certainly be a good idea to change the ratio to accomodate the grist bill in the particular recipe. I just wanted to put a stake in the sand to get the discussion started. As you mentioned, there would be some liquor tied up in the system (pump, tubing, etc) so this would have to be compensated for as well.

If you're heating your mash via the HLT, are you talking about through a heat exchange coil? If not, where will you heat your sparge water?

My proposal would be to test it as a continuous system where the HLT and sparge water are one in the same. The strike water would be fed into the tube and recirculated back into the original tank (heated by gas or electric coil) where it would be mixed with the remaining hot water before being sent back into the column. I guess my thinking was that the water would continue to extract/recirculate from the grains until either the desired SG was reached or the mash was deemed complete otherwise.

Last.... I wouldn't mash in PVC.

Actually, now that I think about it, I would like something clear so I could monitor the fluidization. Probably PC or glass (which could be a bit pricey),

 

[BioBeing]

I like the sound of it. You might want to look into expanded bed chromatography for some more ideas. [Just replace "resin" with "grain"]. I have never actually used this technique, but I think it is basically what you are suggesting. Continuous flow should give everything a chance to mix well, so I'd guess efficiency would be high. After recirculating, collect the wort then pump in some fresh sparge water from the top (collect at the bottom), to make sure you get good recovery.

 

[Bobby_M]

This is basically a no sparge technique similar to how the Brutus 20 is designed. It is relatively simple but efficiency will definitely suffer because all the liquid tied up by the grainbed will be at the equilibrium gravity of the whole wort system. In other words, if you have 12lbs of grain that holds about 1.5 gallons of liquid and a total wort OG of 1.050, that's 75 gravity points locked into the grain. If you can live with lowered efficiency, that's fine.

As an alternative, you'd be really surprised how easy and efficient a smaller converted cooler can be with no need for recirculation.

 

[kladue]

Interesting idea, but might work better if one used a perforated tube in center for return and screened liner to permit flow from outside to inside of bed. Keeping the cross section size to 3"-6" would permit high system flow without serious compaction of the grain bed or the need to fluidize the grain bed. Only hurdle I see is finding suitable material for outer tube and fabricating removable liquid tight ends for mash loading and cleaning, classic herms operation should work well.