Author Topic: Electric urn as double boiler.  (Read 1467 times)

Offline Shalloy

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Electric urn as double boiler.
« on: July 23, 2012, 10:18:38 PM »
Hello,

This is my first post. Ive just bought myself a cheese making kit and am going to try and make some blue cheese. I have a 20 litre urn that I was going to use as a double boiler setup by sitting a pot inside the urn, resting the handles on the edge of the urn, then filling the urn until the water covers an inch or 2 of the pot bottom.
Then use a temp controller  (STC1000) to hold the temp at 32C.

What Im not sure about is if I should put the probe from the temp controller in the water, or do I need to be more accurate and have the probe sitting in the milk itself? The temp controller will hold temps at a .3C variance so if the water is held at this temp then I would think my milk will hold steady at this too.


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Offline Shalloy

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Re: Electric urn as double boiler.
« Reply #1 on: July 24, 2012, 10:11:46 PM »
Someone????  Anyone?????

Offline mtncheesemaker(Pam)

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Re: Electric urn as double boiler.
« Reply #2 on: July 24, 2012, 10:33:11 PM »
Hi. I'm not sure exactly what the setup is that you're describing, but my inclination would be to measure the temperature of the milk. You're aiming for a particular milk temp for any given recipe, and the temperature of your water jacket may not be exactly the same as the milk. IMHO.

Offline knipknup

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Re: Electric urn as double boiler.
« Reply #3 on: July 25, 2012, 07:40:43 AM »
I use a similar setup with a pot and electric element used to heat water. I set my smaller pot of milk into this reservoir as a double boiler. I set the temp controller to heat the water but measure the milk directly with a thermometer.

Things to note:
- water will heat and cool over time, so it is easy to overshoot if you try to move too fast. Cut the power a couple degrees prior to your target and stir to avoid overshooting.
- once you hit your temp, the water does a good job holding the heat and I've found that simply adding a lid can add a few degrees if needed.
- make sure to stir the milk for even heating.
- the higher the water level up the side of the milk pot, the more even the heating.
Cheesy man, totally cheesy

Offline Shalloy

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Re: Electric urn as double boiler.
« Reply #4 on: July 25, 2012, 10:49:12 PM »
Thank you for the information.


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Offline Kaiser Soze

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Re: Electric urn as double boiler.
« Reply #5 on: September 17, 2012, 03:58:07 AM »
I'd suggest measuring the temperature of the outside water, not the milk itself. If you measure the milk, the water will keep heating until the milk is at temperature, but due to the fact that heat transfers slowly to the milk, there's real issue of overshooting the correct temperature. If you measure the temperature of the water bath, while temperature rises will be slow, the milk will eventually heat to the correct temperature assuming that you stir the milk. As mentioned, measure the temperature of the milk with a separate thermometer.

Adding a fish tank bubbler into the urn water bath will ensure that the water is constantly circulating, and you don't get stratification of heat layers throughout the water bath.

Finally, if you swap the STC-1000 out for a PID, you might get a more accurate system, allowing you to measure the temperature of the milk directly. From my understanding, a PID will 'learn' your system and prevent overshoot/undershoot. That's assuming that you heat the same volume of milk each time. I should clarify - I don't use a PID, that's just my understanding of how they work.