Accurate temperature control for water heater.

[Mick tozer]

Hi,this is my first post,I'm looking to make a small heated water bath to accurately warm and temper chocolate,sweets are my hobby...the commercial tempering machines are quite expensive,so I wondered if it would be possible to build a simple control circuit with a sensor,then I wondered if I would have to modulate the heater rather than just on/off...the problem with chocolate tempering is it needs to be very accurate,a couple of degrees makes s difference,would appreciate any thoughts. I'm an ex engineer and now a plumber,but my electronic knowledge is sketchy! Thanks.

 

[kellys_eye]

Modulating the heater shouldn't be necessary given the latency of the liquid you're heating but consider having a circulation system to thoroughly 'mix' the liquid being heated.

Either way there are numerous thermostats (electronic) that can manage the control process - they usually (but not always, so check) come with the relevant temperature sensor.

I have a junk box digital controller I bought via eBay (Chinese delivery) that is programmable for upper and lower limits, hysteresis etc that cost me (IIRC) around $20.

 

[Mick tozer]

Thanks Kelly,I'll do a check on ebay.

 

[(*steve*)]

The answer is a sous vide machine.

There are various immersion type sous vide heaters that include circulating pumps. These devices typically have PID controllers and accuracy to a fraction of a degree.

One of my colleagues used his sous vide cooker for tempering chocolate quite frequently.

Edit: obviously (I hope) with this method you put the chocolate in a bag, all of these methods keep a water bath at a highly consistent temperature.

 

[Mick tozer]

Wow! That's brilliant Steve,I've heard them mentioned on cooking programs,sounds like the way to go,especially with the accurate temp control.