Do I even need to recirc for an overnight mash?

[kohalajohn]

I’m starting to wonder if recirc is even necessary. In my circumstances.

In an overnight, full volume, small batch mash in my Brewzilla, I have been running the recirc pump, on low, with the hose coiled and resting on the mash, under water.

I understand that advantage of recirc is to get even mash temp to every bit of starch.

Yeah, but surely an overnight is so long that no speck of starch can escape

Also I insert the rapt Bluetooth thermometer in the middle of the mash. So temp is well controlled.

What do you think?

 

[doug293cz]

Not really, unless you intend to have heat input to maintain a consistent temperature. You might not need it even then, if you can adjust the heater surface temp to be just a few degrees higher than the target mash temp without having to depend on flow to transfer excess heat from the element.

Brew on

 

[kohalajohn]

I think I agree. In my particular circumstances of course.

The Bluetooth thermometer controls the heat source, so that the center of the mash maintains the desired temp. When I use this thermometer I turn off the machines internal temp sensor.

The Brewzilla literature even says that this Bluetooth system is so precise that I can even turn off the PID algorithm altogether.

Next mash I’ll do without recirc and see how that goes.

 

[kohalajohn]

With my system, the only advantage I can see with recirculating, is that the flow may help intermingle the wort in the stagnant space between the basket wall, and the wort in the main body.

But I’m guessing that the mere thermal currents, spread out over eight hours, should do some intermingling for me.

I should take OG readings and find out.

 

[doug293cz]

I think I agree. In my particular circumstances of course.

The Bluetooth thermometer controls the heat source, so that the center of the mash maintains the desired temp. When I use this thermometer I turn off the machines internal temp sensor.

The Brewzilla literature even says that this Bluetooth system is so precise that I can even turn off the PID algorithm altogether.

Next mash I’ll do without recirc and see how that goes.

Time lag between when the controller sends power to the heating element, and when the controlling temperature sensor detects a temperature increase leads to unstable, or at least oscillating systems with significant temperature overshoot. This means that the heating element surface is much hotter than the location of the temperature probe (I have personally dealt with this problem in another context.) If I understand what you are proposing, I wouldn't trust it.

Brew on :mug;

 

[kohalajohn]

Time lag between when the controller sends power to the heating element, and when the controlling temperature sensor detects a temperature increase leads to unstable, or at least oscillating systems with significant temperature overshoot. This means that the heating element surface is much hotter than the location of the temperature probe (I have personally dealt with this problem in another context.) If I understand what you are proposing, I wouldn't trust it.

Brew on :mug;

I see.

Perhaps the best way to achieve temperature control then, is to conduct an overnight vorlauf after all

Forgive me if I mention something everybody knows, but I recently bought a Heat Diffuser Plate for the Brewzilla. I think this is relevant.

Before, the recirc pump would pull wort down through the middle of the mash, as the current was pulling down into the central drain hole

Now, wort exits the bottom of the basket, hits the solid plate, is pulled to the outside edge of the plate and flows down the gap to the warm floor. It then flows over the warm floor. It flows inward toward the central hole, heating up as it goes and is finally drawn down the central hole and up and over the top of the bed.

In light of Doug’s comments I now think I’ll stay with my overnight recirculation.