Mild Brew Day and Maiden Run of Fermentation Chiller

[ISUBrew79]

This weekend I made a batch of Mild that I plan to give away for Christmas. Since I plan to keg this beer and bottle it from the keg, I think there will be plenty of time to get it ready by Christmas.

The grist for the Mild.

The mash

I decided to save some propane and heat the sparge water on the stove. I was also simmering some chicken to make a batch of chicken soup.

First runnings going into the kettle

The wort coming up to a boil

Chilling the wort

The starter of WLP002 on my homemade stirplate. I made the starter three days before brew day because the vial "expired" in May. The English Ale strain flocculates so well that I decided not to bother cold crashing the starter this time.

I poured out the spent wort and added some fresh wort to try to get the yeast back into suspension before pitching.

 

[ISUBrew79]

The Mild was the first beer to be fermented using my new fermentation chiller. I have been using the swamp cooler method for the majority of my beers, and decided that I was tired of swapping out frozen water bottles all the time. My wife got me a Johnson A419 temperature controller and a stainless thermowell, so I decided to construct a fermentation chamber. I live in a apartment where space is at a premium, and this had to be something I could remove for storage when not in use.

Here is the fermentation chiller I designed. I haven't came up with a name for it yet, but Beer-2-D-2 might be appropriate. It consists of a cooler filled with ice water. The fermenter is submerged in a water bath in the fermentation chamber. A submersible pond pump forces coolant water through a copper coil submerged in the water bath in the fermentation chamber. The chamber itself was constructed from two round plastic totes that I wrapped with two layers of Reflectix insulation.

I used my 5 gallon MLT as the coolant chamber. I am using frozen water bottles and ice packs to keep the water icy cold. The pond pump is in the bottom, and you can see the coolant in/out lines.

A close-up of the temperature controller. I currently have it set at 65 F with a 1 degree differential.

Here is an internal view of the fermentation chamber. I salvaged my old wort chiller to use as the cooling coil. I initially had the thermowell in the interior of the fermenter itself, but found that the temperature of the contents of the fermenter would continue to drop by several degrees after the setpoint had been reached. I now have the thermowell in the cooling water bath. This way, I can maintain the temperature of the water bath in a more responsive fashion. At some point, I will install another thermowell in the fermenter so I can determine the temperature gradient between the fermenting wort and the cooling bath at any time.

Here is a top view of the fermentation chamber. On the left side, you can see that I have another small pond pump in the bottom of the water bath. I ran a length of tubing from the pump to near the surface of the water. This pump runs constantly to circulate the coolant water and keep the water temperature constant throughout.

 

[MeatyPortion]

That's a pretty ingenious set up there. Thanks for the pix and the ideas.

 

[Runyanka]

So you have the control set to turn on the pump when the heat rises? I think I just found my next spring project

 

[ISUBrew79]

So you have the control set to turn on the pump when the heat rises? I think I just found my next spring project

Yeah. I have the probe from the temp controller in a thermowell submerged into the cooling bath. When the temp exceeds the setpoint, the pump in the ice water cooler kicks on, sending chilled water through the copper coil. I have it set to a 1 degree differential, which means that the pump will run until the temp is 1 degree below the setpoint.

I still need to figure out what kind of temp differential there is between the wort inside the fermenter and the cooling water bath surrounding it. Since water has a much higher heat capacity than does air, I think there will be a smaller temperature variation between the wort and the coolant water than the wort and ambient air in a typical fermentation fridge setup. I will report back once I test this theory.

 

[android]

well done!