[wuertele]

After reading the recent mash thickness discussion, I started wondering what would happen if I continuously recirculated my total water through my mash at high speed?  Would there be undesirable extraction effects (eg. tannins or the like)?

The idea is basically to do a "no-sparge" mash, but crazy-recirculated.  I would do it like this:  put my normal strike water into my mash tun, put my normal sparge water into my boil kettle (about the same amount into each).  Heat MT to strike temp and BK to infusion temp.  Dough in my grains into the MT, mixing in A LOT of rice hulls in order to support a fast flow with minimum suction (to prevent stuck mash).  Start pumping from the MT to the BK, and pump from the BK into the MT.  Circulate like this for the whole rest at the maximum flow rate I can sustain.  Once the mash is complete, stop pumping from the BK to the MT, and wait for the BK to fill to the desired volume.

Does anyone regularly mash this way?  Does large wort flow past the grains extract undesirable compounds?

I understand that the larger volume of water in contact with the grain would impact the pH.  I guess I could compensate by adding an appropriate amount of acid malt to the mash.  What else would I have to be careful of?

[tomsawyer]

I don't think it would extract anything that wouldn't be extracted by a simple no-sparge.  That said, I don't know that the recirc would do anything positive either.  I kind of think sucking the grist down into a tight cake like you get when you lauter, would probably be bad for conversion.

I do think an occasional stir to rouse the starch particles into solution might be a good idea.  Maybe even a motorized mash paddle keeping everything moving.

[oscarvan]

Sounds like a lot of work........

I do stir the mash a few times.

[tom]

Tannins are extracted when the pH gets above 6 and the temperature is above 170F.

Recirculating the wort will clear any husks, granules and protein from the wort andmay result in clearer beer. Just keep the flow rate lower than what will stick the mash. I worry about oxygenating the wort so I just recirculate when I'm adding heat.

Cheers

[wuertele]

I don't think it would extract anything that wouldn't be extracted by a simple no-sparge.  That said, I don't know that the recirc would do anything positive either.  I kind of think sucking the grist down into a tight cake like you get when you lauter, would probably be bad for conversion.

I do think an occasional stir to rouse the starch particles into solution might be a good idea.  Maybe even a motorized mash paddle keeping everything moving.

The purpose of the rice hulls would be to enable fast recirculation without sucking the grist down into a tight cake.

The fast recirculation would serve two purposes:

1.  avoid the need to stir the mash, since the fluid flow should be fast enough to get grains in contact with a lot of wort

2.  speed up the lauter stage

The BK-as-large-grant would serve three purposes:

1.  for a given mash tun size, allow bigger beers to be mashed in no-sparge mode

2.  at the end of the final rest, half the wort is already in the BK, which reduces the lautering time

3.  since a large volume of wort continually passes through the BK, a propane burner can be used to achieve fast temperature steps with much lower risk of scorching.  Also, heating for the boil can be started the moment the final rest is completed.

I think that this system would achieve the fastest possible mash/lauter, while allowing fast temperature steps, and very thin mashes.  It is also very simple, because once it is running the only manual work to change from mashing to lautering is to turn off the BK->MT pump.

[tomsawyer]

I see what you're saying, but I still don't think your cake will be light and fluffy just because of some additional rice hulls.  Even with wort running through it, I don't see the enzymes doing as good of a job on the starch grains if they're packed together.  But its something that might have to be tried to find out.

[dshepard]

I don't think it would extract anything that wouldn't be extracted by a simple no-sparge.  That said, I don't know that the recirc would do anything positive either.  I kind of think sucking the grist down into a tight cake like you get when you lauter, would probably be bad for conversion.

I do think an occasional stir to rouse the starch particles into solution might be a good idea.  Maybe even a motorized mash paddle keeping everything moving.

The purpose of the rice hulls would be to enable fast recirculation without sucking the grist down into a tight cake.

The fast recirculation would serve two purposes:

1.  avoid the need to stir the mash, since the fluid flow should be fast enough to get grains in contact with a lot of wort

2.  speed up the lauter stage

The BK-as-large-grant would serve three purposes:

1.  for a given mash tun size, allow bigger beers to be mashed in no-sparge mode

2.  at the end of the final rest, half the wort is already in the BK, which reduces the lautering time

3.  since a large volume of wort continually passes through the BK, a propane burner can be used to achieve fast temperature steps with much lower risk of scorching.  Also, heating for the boil can be started the moment the final rest is completed.

I think that this system would achieve the fastest possible mash/lauter, while allowing fast temperature steps, and very thin mashes.  It is also very simple, because once it is running the only manual work to change from mashing to lautering is to turn off the BK->MT pump.

This sounds like a giant RIMS with the BK being the heat chamber. I have a HERMS and recirculate during the entire mash. I am not sure I understand what a "fast" recirculation accomplishes. I do see how using the BK as your heat source could potentially speed up steps since you would be using a nice large heat source with a larger mass so there should little or no overshoot, but you still have to wait for the enzymes to do their thing. On my system lautering only takes about 10-15 minutes to pump 14 gallons of wort. I could speed that up if necessary, but haven't seen the need.

I think it sounds like a neat experiment waiting to happen, keep us posted. 

[malzig]

I wouldn't expect any advantage to "fast" recirculation unless it's needed to avoid scorching.  If I understand correctly, you're mostly trying to keep things moving to increase enzyme/substrate kinetics, which wouldn't require fast movement.

[tomsawyer]

Would the mechanism of incomplete conversion be a matter of reaction kinetics?  Too high of a sugar concentration localized around the starch grit?

One would assume that a finer crush would give you smaller particles and therefore faster/more complete conversion.  I've tried finer crushes and I really don't see that much difference.

[brewandski]

Tannins are extracted when the pH gets above 6 and the temperature is above 170F.

Recirculating the wort will clear any husks, granules and protein from the wort andmay result in clearer beer. Just keep the flow rate lower than what will stick the mash. I worry about oxygenating the wort so I just recirculate when I'm adding heat.

Cheers

Is that a stage when oxygenation is something to be concerend about?  New to all grain, just wondering.