Mash Recirculation?

[Markalanbrown]

Can you recirculate mash draining with a pump, to increase brew house efficiency and clarity, or is there an temperature inconsistency issue that will effect the taste of the beer?

 

[eric19312]

Yes it is very possible to recirculate mash on homebrew scale.

Whether this increases brew house efficiency or clarity are much more complex questions as neither is determined entirely by what goes in in the mash itself.

 

[Markalanbrown]

Will I lose that much heat going out the bottom to the top of the pot (Pot-hose-ball valve-hose-sparge nozzle)?
How will that affect the beer/
And is using a cooler (which I do now) more effective?

 

[eric19312]

If you mash in a metal pot without insulation you will lose quite a lot of heat whether you recirculate it or not. My guess is you will lose a little more with recirculation but in either case it is probably too much heat loss.

A cooler will hold temps better. When mash temperature falls too low the enzymes stop working or at least slow way way down. When that happens conversion of starch to sugar slows down and you risk not converting all your starch. I say risk because there is fair amount of evidence out there that it is very possible to get near full conversion with pretty short mash times. 20-30 minutes may be all you need if you grind it fine enough like you can with BIAB brewing. My personal experience with 3 vessel recirculation system is I need a coarser grind to support recirculation and longer mash at stable temperature works better for me.

 

[Markalanbrown]

If you mash in a metal pot without insulation you will lose quite a lot of heat whether you recirculate it or not. My guess is you will lose a little more with recirculation but in either case it is probably too much heat loss.

A cooler will hold temps better. When mash temperature falls too low the enzymes stop working or at least slow way way down. When that happens conversion of starch to sugar slows down and you risk not converting all your starch. I say risk because there is fair amount of evidence out there that it is very possible to get near full conversion with pretty short mash times. 20-30 minutes may be all you need if you grind it fine enough like you can with BIAB brewing. My personal experience with 3 vessel recirculation system is I need a coarser grind to support recirculation and longer mash at stable temperature works better for me.

Thanks for all the insights (and I feel like I am out of my depth) Would the cooling in a metal pot still be trur if I buy some foiled insulation and keep the flame on low to keep temps up?

 

[eric19312]

If you are adding heat you need to circulate or you will get hot spots.

 

[day_trippr]

Can you recirculate mash draining with a pump, to increase brew house efficiency and clarity, or is there an temperature inconsistency issue that will effect the taste of the beer?

Whether a direct-fired mash tun or a HERMs configuration, if anything a well-executed recirculated mash will result in more even temperature through the grain bed. Otoh, a badly channelled recirculation can cock that all up, perhaps worse than not recirculating at all.

Metal tuns lose heat freely, so when recirculating there needs to be a heat source to prop up the mash temperature. Reflectix can slow down the thermal loss but can't prevent it entirely...

Cheers!

 

[enganeer]

I made a re-circulation setup using my boil pot, pump and a cooler. I controlled the flow by using the valve body at the pump. I think next time I will use I will try and do a stepped mash.

 

[brewdude88]

recirculating has been very beneficial to my beers. Since I started recirculating and fly sparging, I haven't used gelatin fining once and my beers are satisfactorily clear within a few days of kegging.

 

[Jayjay1976]

Do you BIAB?

I used to recirculate throughout the mash using a small MKII pump, but it didn't seem to clarify the wort that much. One note of caution, if the mash becomes compacted from too much flow or too fine a crush, even a small pump is capable of creating enough vacuum to collapse your false bottom. If you use a heavy duty FB with standoff legs it can either rupture the grain bag or collapse your kettle, and might even cause the standoff legs to pierce through the kettle bottom. My 11 gallon SS kettle has 5 dimples protruding on the bottom caused by this; I'm just lucky I caught it in time. Be careful. My planned workaround is to install a sight glass so that if a vacuum forms it can act as a snorkel/vacuum relief and draw air instead of damaging anything. In the meantime I don't recirculate at all, instead stirring the mash to equalize its temperature.

 

[mongoose33]

Unless one is doing LODO stuff, it's not clear to me how much recirculation will add to efficiency, if anything. I always had excellent efficiency doing BIAB, with a couple of stirs during the mash to ensure everything was mixed well.

I do a recirculating RIMS system, but that's largely to control mash temps, do step mashes, and limit O2 exposure.

If the point is clarity of the wort going into the BK, no reason why that can't be done in a traditional mash tun, lautering until clear (adding that back to the top of the tun), and transferring clear wort to the BK.

A good recirculation can really clarify that wort--takes typically about 10-12 minutes for it to clear out, but when it does, I get this:



Here's my mash tun covered with reflectix:

 

[brewdude88]

I use a robobrew without the malt pipe. The grain bag sits on the false bottom that came with the robobrew and it definitely bends a little under the weight, but the false bottom is supported very evenly across the bottom and is only there to keep the bag off the heating elements. I also wet condition my grain before milling and most husks stay relatively whole, no stuck sparge at all since doing away with the malt pipe. I only open the valve controlling flow to 25% max to avoid compacting the grain bed and upsetting the top of the grain bed. My progression for the last 2 years has been-

- single pot BIAB--- 68% efficiency, copious amounts of trub and always had to use gelatin fining in keg to clear beer in reasonable time.
- robobrew used as intended--- 76% efficiency much clearer wort, but malt pipe is a pita
- robobrew used current way with batch sparge---- 83% efficiency, had to recirculate batch sparge for a long time and still got more cloudy wort.
- robobrew used current way with fly sparge--- 91% efficiency, crystal clear wort (until the hot break of course)

The only bad thing about the current method is adjusting my favorite recipes to taste the same with adjustments for the higher efficiency. I'm trying to rationalize the specialty malt amounts as a ratio of specialty grain to water volume instead of as a percentage of the malt bill.