Oil in herms? Anybody here do it?

[fraser_john]

I'd be a bit worried about using oil, due to the flammable nature of it.

The issue I have found, is that is is pretty easy to forget to turn the PID control of the HEX off after sparging, meaning that the PID sensor is no longer in wort and is cooling off, meanwhile the PID is flat out trying to get it up to whatever the set point is.

For me, I use glycol, and this particular scenario has occurred twice and has resulted in boiling the glycol!! If it were oil .... eeps, a hard mess to clean up and worse, a flammable one!

Solution is to get yet another PID or even an STC1000 and place it between the PID output 240V and the HEX, the STC1000 would have a max temp set at 96c say, so regardless of what the PID is trying to do, the STC will only allow the glycol to reach 96c.

Easiest solution though is turn the damn PID off whilst sparging, easy enough to say, hard to do when processes start failing on brew day!

 

[Kingy]

At the moment i only use an stc1000 on the exit of the hex to control.
Where sort of glycol did you use fj and where did you source ig from. I noticed there is an organic corrosive preventention glycol availavle also.

 

[Kingy]

so ive looked around and the cheapest option for 6litres of food grade glycol with rust inhibitor is over $100. Looks like ill just use this beast until it rusts through lol. And put that $100+ towards a purpose built staino one in the far future.

 

[fraser_john]

At the moment i only use an stc1000 on the exit of the hex to control.
Where sort of glycol did you use fj and where did you source ig from. I noticed there is an organic corrosive preventention glycol availavle also.

Just the cheapest glycol I could get from supercheap auto! There is talk of food grade stuff, but, if you are going to have a leak, it will be wort into glycol reserve, resulting in the HEX overflowing at which point you are probably going to have enough issues to throw the batch out anyway! So, I just went with the "cheap" stuff.

 

[Kingy]

So with not much to do i bit the bullet and done some testing.
In my 80 litre aluminium mash tun filled with 30 litres of water. The oil heated up on average 0.6degrees every 5 mins faster than the water did in the same test from 21degree start to 66degree finish.
The elemnt turns off at 66 and comes on at 65.7.
With the water in the hex the swing was from 66.2(overshot 0.2degrees after element turned off), down-65.6 where as with oil in the hex the swing was 66.3-65.7.
One thing that stood out was the element "off" period on average with water in hex was 1min44secs where as with the oil it held temps for an average of 5mins32secs before the element started up again.
Both ramp times from 66degrees to 76 degrees where the same at 11mins30secs.


For me the oil is a lot quieter as it doesnt make a noize. It holds the temps longer. I wont have to drain the hex after each brew and it wont rust and is non toxic.
$13

 

[Camo6]

https://www.youtube.com/watch?v=0mduR6SOcdY

I'll pray for you Kingy.

 

[Kingy]

Im sure my heating element is safer than a naked flame lol

 

[stux]

Should just put a hermit coil in a deep fryer...

 

[TheWiggman]

Safer than a naked flame yes but oil can ignite under heat alone. This site has some good reading. You'd have to be pretty negligent to let this happen but I've made some dumb errors under the influence of alcohol while brewing. As have 100% of AG brewers dare I say.
Cheers for doing the test, confirmed my suspicions. Will be sticking to much cheaper water.

 

[yankinoz]

If rust is a problem you may try glycol or antifreeze mix rather than oil.

Many years ago a white coloured oil similar to cutting oil was mixed with water in car and truck radiators to eliminate corrosion of steel welsh plugs that were common in older automotive engines.

Better still just use a stainless steel vessel in place of the fire extinguisher....

Be very careful with ethylene glycol to avoid leakage and contamination. It is extremely toxic.