Coffee maker rims system?

[dogslapbrewery]

Has anyone attempted to make a rims system out of the heating coil from a coffee machine? I've found very little feed back about this. I was thinking one of those tiny food grade solar pumps and a stc 1000. Thought this would be a great inexpensive way of maintaining or maybe even step mashes with depending on how quick this coil can heat?

 

[PlexVector]

I would expect it to be a high density heating coil rather than low density. Could scorch the wort.

 

[BrunDog]

True dat.

 

[alphaomega]

I actually have the coil from a drip coffee maker in my spares bin. Planning to use it in a very similar setup you are describing, but in a diy sous vide, just haven't gotten around to it yet.
I imagine it could work, but I wouldn't expect great results. You could always add a rectifying diode in series with the element to halve the power. And the STC is not really a suitable controller, but if you limit the power it might be acceptable.

 

[dyqik]

I would think it would have enough output power, but remember that the drip coffee maker is only set up for a flow rate of about 4-6 cups* of water through it in about 3-4 minutes, driven by boiling of the water in the element. I'd be surprised if it could handle the flow-rate you need for effective RIMS on a reasonable size batch as well as the flow-rate you need to prevent scorching, even when driven by a pump.

*coffee cups marked on coffee machines are usually 5oz, so smaller than regular 8oz baking cups

 

[Mista_Sparkle]

OK, So I happened to be considering the same thing and had an old coffee maker that I saved for this or a similar purpose...

The heating element I have is a 900 watts protected/controlled by a klixon set to 145°C(293°F). It has an active length and a star shaped cross section inside. The total perimeter of the tube is ~1", though I imagine that the star profile is to increase turbulence and promote better heat transfer to the water. As the length of the tube is only about 8" pressure drop is minimal for moderate flow rates ~.1psi at 2l/min

I checked power usage and flow rates by running a batch of water through my coffee maker to get a better idea of what is actually happening.
I stuck my thermometer down the output to verify the temperature is around boiling, as it is, ~97°C (207°F). Measured flow rate is .198L/minute, which matches the expected value for a 1kW element and 80°C temperature rise.

At full power, it will do ~16°C (29°F)/(L/minute)

If you run 2L/minute you can have a reasonable temperature rise across the element and most likely have no scorching as you will be cooling the element below the boiling point of the wort, since flow is turbulent and well mixed.

Actual power density is somewhere around 125 watts/in^2 but with forced flow, scorching should not be a problem.

If you do go this route, I would probably leave the temperature switch on it and possibly wire it into a kill circuit for safety in case a pump stalls or something and the element starts running dry.

I hope that made enough sense...

 

[augiedoggy]

hello

you had a question?

If your considering this I strongly recommend against it, it will almost certainly denature the enzymes in the wort and cause very poor attentuation. The watt density of these elements are designed for heating water only. with the low cost of other homemade options I see little point in this with so many shortcommings.