Recirculating Mash

I’ve noticed that the top of my mash is always a little warmer than the bottom. Heat rising or something like that? What about recirculating from top to bottom? I'm thinking of drawing from a strainer partially submersed in the top of the mash to avoid the thick mash and then pumping into the ball valve in the bottom of the tun. It might keep the grain bed from compacting and stir up the mash for better conversion.

Or is this already being done and I just missed it?

BigFloyd do you have problems with heat loss by continuously pumping the wort? I'm seeing the same thing as the OP in regards to temp stratification in the Mash Tun (10G water cooler).

AnOldUR said:

I’ve noticed that the top of my mash is always a little warmer than the bottom. Heat rising or something like that? What about recirculating from top to bottom? I'm thinking of drawing from a strainer partially submersed in the top of the mash to avoid the thick mash and then pumping into the ball valve in the bottom of the tun. It might keep the grain bed from compacting and stir up the mash for better conversion.

Or is this already being done and I just missed it?

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Is it possible (no, it's reality) that the pump running at full motor speed might be adding heat to your wort as it passes through it??

How can you recirculate from top to bottom?

Why not just buy a variable frequency drive so you can slow the pump down with a knob?

USAFSooner said:

BigFloyd do you have problems with heat loss by continuously pumping the wort? I'm seeing the same thing as the OP in regards to temp stratification in the Mash Tun (10G water cooler).

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No. The temp of the mash in my E-BIAB system is regulated by a PID controller that's hooked up to a temp probe in the keggle. If the temp drops, the PID (via a solid state relay and a 120V/240V contactor) sends juice as needed to the 5500W 240V electric element to maintain the mash temp where I've set it on the PID.

bethebrew said:

Is it possible (no, it's reality) that the pump running at full motor speed might be adding heat to your wort as it passes through it??

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Not by any significant amount. The pump gets warm, but not much, if any, warmer than the 148-156*F mash.

bethebrew said:

How can you recirculate from top to bottom?

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The pickup tube is near the bottom of the keggle and the return line runs to a sparge arm that sprinkles the wort back over top of the grain bed.

bethebrew said:

Why not just buy a variable frequency drive so you can slow the pump down with a knob?

Click to expand...

Because Chugger and March pumps are magnetic drive. According to the folks that make them, you regulate the flow (from full to nothing) by restricting it with a 1/2" stainless ball valve on the output side. The key is to not run them dry.

BigFloyd said:

The pickup tube is near the bottom of the keggle and the return line runs to a sparge arm that sprinkles the wort back over top of the grain bed.

Click to expand...

But what I proposed is the opposite. Putting a strainer in the top of the mash and drawing the liquid from inside that area that’s been isolated from the thick mash. Then pushing that liquid up through the bottom lautering device; either a false bottom, braid, or whatever. The idea is to keep the mash from compacting and better exposing the starches to enzymes; and to reduce stratification of heat and sugars. Probably a solution to a problem that doesn’t exist, but I thought I’d throw it out there and see what people thought.

AnOldUR said:

But what I proposed is the opposite. Putting a strainer in the top of the mash and drawing the liquid from inside that area that’s been isolated from the thick mash. Then pushing that liquid up through the bottom lautering device; either a false bottom, braid, or whatever. The idea is to keep the mash from compacting and better exposing the starches to enzymes; and to reduce stratification of heat and sugars. Probably a solution to a problem that doesn’t exist, but I thought I’d throw it out there and see what people thought.

Click to expand...

We got a bit sidetracked there, did we not?

In your situation, I think that the occasional stir would accomplish your goal.

Wouldn't the grain bed filter be set upside down then?

I don't think the guys who recirculate throughout the mash ever stir.

This is only for recirculating the mash. Lauter would be done as ususal, out the bottom of the tun.

AnOldUR said:

I don't think the guys who recirculate throughout the mash ever stir.

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I assume that is correct.

I was just thinking about the issue of having a different temperature at the top of the mashtun vs lower in the mashtun.

It's been a long time since I've checked the temperatures in both places and not recirculated (pre-HERMS, so at least a few years) but it seems to me that I didn't have a temperature differential like that. I preheated the MLT (it was a cooler), and had a temperature probe near the bottom, about 3 inches above the false bottom, and would check the temperature at the top with my thermapen. I remember when I mashed it that I would stir thoroughly, until the temperatures were equalized throughout, but I don't remember having different temperatures later on.

I don't know why the temperature would be warmer at the top, as I would assume that the mass would "hold" in the temperature. I can't figure out why that would be. How many degrees difference are you noticing?

Yooper said:

How many degrees difference are you noticing?

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It’s only a few degrees. Not enough to make a lot of difference. I'm mashing in a stainless kettle and the insulation I'm using is not as good as your old cooler.

I just got a pump, but mainly to go from the MLT to the kettle, so that I don't have to lift 12 gallons of wort from the floor. Recirculating is just something I'm considering. Going backwards from the conventional way seemed like an interesting idea from both a heat and grain bed standpoint. I have the same disconnects on both sides of the pump, so reversing it would be easy. But from the lack of positive response here, probably not something worth attempting.

AnOldUR said:

It’s only a few degrees. Not enough to make a lot of difference. I'm mashing in a stainless kettle and the insulation I'm using is not as good as your old cooler.

I just got a pump, but mainly to go from the MLT to the kettle, so that I don't have to lift 12 gallons of wort from the floor. Recirculating is just something I'm considering. Going backwards from the conventional way seemed like an interesting idea from both a heat and grain bed standpoint. I have the same disconnects on both sides of the pump, so reversing it would be easy. But from the lack of positive response here, probably not something worth attempting.

Click to expand...

I wonder if you're getting some grainbed compaction, so that you have more fluid-y mash at the top, if you're noticing a temperature difference. How thick/thin do you mash?

Yooper said:

How thick/thin do you mash?

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For most of my beers I mash thinner than normal, about 1½ to 1¾ qts/lb. I'm pretty sure that any heat stratification is more of an insulation issue.

I'm happy with my efficiency. It's pretty consistently in the 75% area, but I thought recirculating might give me a little boost (not that I really think I need it.) I don't have a problem with compacting now. The reason I mentioned it was that I thought that if I started recirculating throughout the mash it might become a problem. That's where the top to bottom idea came from. Forcing thin mash into the ball valve until it's time to lauter, and then reversing the pump to go to the kettle.