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[pacoast]

I've decided that I need a better proofing box for my pizza dough. My sourdough "proofer" is doing double duty for the moment, but as it's only a dimmer switch controlled lamp in a picnic cooler.. the temperature control is pretty coarse. And it's also tight on space.

I think that most people are using Koolatrons as they will both heat & cool. But I was wondering if there was any obvious reason why I couldn't modify a wine cooler (or bar fridge /mini fridge) to do the same thing. A compressor based fridge cools better and uses a lot less power than a thermoelectric (Koolatron). For heating, I think that I have enough spare parts around to do something. I was thinking of using a notebook fan to blow air over a power resistor. And a PID controller (temperature controller) that would control & display the temperature.

Does anyone see any obvious flaws in this plan? I was also wondering if anyone sees any advantage (or has experimented) with boosting humidity in their Koolatrons? I could either find a small ultrasonic humidifier or rig some kind of small steam generator. Humidity control is a standard feature on commercial proofing cabinets, but I'm not sure how beneficial it would be for us?

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[pacoast]

Picked up a generic glass door bar fridge for this project. $60 at a freight consolidator. One nice thing is that it has almost four times the interior volume as the MR-138. Haven't had time to modify it yet, so for now it's just another fridge.

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[thezaman]

the first mod is to drink the alcohol. i am thinking that if i want to use a small amount of yeast and ferment dough over  say two day period , i need something like this. i am looking forward to your mods.i think that lower humidity helps dough retard slower . although a dough retarder that bakers use has high humidity and low temperatures . that keeps uncovered dough from crusting.

[pacoast]

This "mini proofer" is a more attractive replacement for the upside down styrofoam chest that I currently use for my starters. And will give me better temperature control for proofing actual pizza, baguette & bread dough. I've picked up most of the parts I need to assemble this (PID, SSR, etc). And have drank the beer in the photo. Just looking for a good price on a humidity sensor.

I'm not sure if there is any real benefit to humidity control or not. If it's only a matter of preventing crusting on open containers, then it's just as easy to use closed containers for home size batches of dough. But it's easy enough to implement, so I'll give it a try & see if higher humidity levels have any other positive influences on the dough.

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[Matthew]

This "mini proofer" is a more attractive replacement for the upside down styrofoam chest that I currently use for my starters. And will give me better temperature control for proofing actual pizza, baguette & bread dough. I've picked up most of the parts I need to assemble this (PID, SSR, etc). And have drank the beer in the photo. Just looking for a good price on a humidity sensor.

I'm not sure if there is any real benefit to humidity control or not. If it's only a matter of preventing crusting on open containers, then it's just as easy to use closed containers for home size batches of dough. But it's easy enough to implement, so I'll give it a try & see if higher humidity levels have any other positive influences on the dough.

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PA,
Once complete can you kindly post the process & parts required, etc.  I purchased a wine fridge.  It has 2 zones & a digital readout which is pretty accurate.  I removed the shelf between the zones & disconnected the top motor so that the whole unit now runs on the bottom motor.  With the mod, the temperature gets to about 68-70 degrees.  I would like to get it to go warmer but I'm not sure how to modify it.

Thanks,
Matthew

[thezaman]

i think higher humidity is going to quicken the rise. my 24 hour dough was a lot slower to rise this week than in the middle of the summer.

[pacoast]

Once complete can you kindly post the process & parts required, etc.  I purchased a wine fridge.  It has 2 zones & a digital readout which is pretty accurate.  I removed the shelf between the zones & disconnected the top motor so that the whole unit now runs on the bottom motor.  With the mod, the temperature gets to about 68-70 degrees.  I would like to get it to go warmer but I'm not sure how to modify it.

Matthew, it depends on whether your fridge is compressor based or thermo-electric (Peltier). From your description, it sounds like your fridge has two Peltiers. A Peltier is an electronic heat pump. It makes your fridge cooler by pumping the heat to the outside of the fridge. However it can usually be made to pump heat in the opposite direction (into the fridge) by reversing the DC power polarity to the Peliter. And adding a fan to the interior heat sink if there isn't one there already. If you do reverse the polarity, watch the fridge carefully at first until you are confident that the Peltier itself is not overheating. If the Peltier fans are unequally sized, it may have more cooling than heating capacity. It might be easier to just reverse the polarity on just one Peliter, so that you are using one for cooling & one for heating. If both Peltiers are the same size, it would be most efficient to use the top one for cooling & the lower one for heating.

If yours is compressor based (like mine), it's more difficult. The compressor will only cool unless you move the evaporator coils into the fridge, which is not really practical. So I will be adding a separate heating circuit, with a flameproof power resistor as the heating element and a low profile notebook fan to circulate air over the resistor.

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[Matthew]

Matthew, it depends on whether your fridge is compressor based or thermo-electric (Peltier). From your description, it sounds like your fridge has two Peltiers. A Peltier is an electronic heat pump. It makes your fridge cooler by pumping the heat to the outside of the fridge. However it can usually be made to pump heat in the opposite direction (into the fridge) by reversing the DC power polarity to the Peliter. And adding a fan to the interior heat sink if there isn't one there already. If you do reverse the polarity, watch the fridge carefully at first until you are confident that the Peltier itself is not overheating. If the Peltier fans are unequally sized, it may have more cooling than heating capacity. It might be easier to just reverse the polarity on just one Peliter, so that you are using one for cooling & one for heating. If both Peltiers are the same size, it would be most efficient to use the top one for cooling & the lower one for heating.

If yours is compressor based (like mine), it's more difficult. The compressor will only cool unless you move the evaporator coils into the fridge, which is not really practical. So I will be adding a separate heating circuit, with a flameproof power resistor as the heating element and a low profile notebook fan to circulate air over the resistor.

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PA,
Thanks very much, It's definately thermo electric, there is no compressor.  There is a fan for the top zone & a fan for the bottom zone.  The top zone is for white wine & the bottom zone is for red wine.  As of now, I completely disconnected the fan (Peltier?) for the top zone.  How do I go about reversing the DC power polarity?

Matt

[pacoast]

There will be wiring leading into the Peltier unit. Probably two or three wires to the fan and two (usually) larger /thicker wires leading the Peltier itself. The Peltier under the heatsink & fan will look like a flat metal plate or a stack of flat metal plates. It runs on DC power, so that one wire will be positive (usually red) and one will be negative (typically black). If you swap the black & red wires to the Peltier, it will transfer heat in the opposite direction. So heat, rather than cool your fridge. Note that swaping the DC polarity on most electronics is a bad idea. But Peltiers will happily run in either direction.

Also note that your power should not be directly connected to the Peltier. Usually the power is in series (connected through) a variable resistance (thermostat) to control the amount of current that goes to the Peltier.

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