Immersion Heater

[Pumpy]

I scored this 2400W Immersion heater with timer for pre heating my mash water before I get up on a Sunday , (my kettle uses gas many people seem to have some method of time saving rather than get up early on a Sunday .

I wonder how long it would take to heat up 13 litres of mash water?


Someone mentioned using it to just get the mash on temperature ( keeping it moving so it dont scorch the grain ), but how do you clean them as I understand they build up a deposit??

Anyone had experience with using them ?

Pumpy

 

[Duff]

G'day Pumpy,

That's the same as I use as mentioned. It takes me 60 minutes to heat 30L to 80C, so for 13L of mash water, say 75-76C then it should be under 30 minutes.

But, it's something that you cannot just set and forget. You will have to stir the water occasionally to prevent stratification as cooler water will sit underneath the heater. I stir mine every 10 or so minutes to get even heating.

Cheers.

 

[Guest Lurker]

Hi Pumpy,

Always love the chance to do some maths.

Spec heat capacity of water is 4187 J/deg kg
You have 13 kg of water
You are raising it from 15?deg C to 75? deg C ie 60 deg

Energy you need to add to the water is 4187*13*60 = 3265860 J

2,400W is 2,400 J/s

Time to deliver 3265860 J at a rate of 2400 J/s is 3265860/2400 = 1360 s
so 23 minutes.

That assumes 100% efficiency. Depending on the wiring, whether you cover the HLT, how well the HLT is insulated, you probably wont do better than 80% efficient.

So at least 28 mins, lets say about half an hour.

 

[Pumpy]

Cheers Duff after you mentioned it
I showed a pic to my Sparky mate and he rocked up with it the next day .

Pumpy

 

[Pumpy]

Thanks GL there are some math wizards on the site same as what Duff reckons

pumpy

 

[Asher]

But, it's something that you cannot just set and forget. You will have to stir the water occasionally to prevent stratification as cooler water will sit underneath the heater. I stir mine every 10 or so minutes to get even heating

Is this true? wouldn't the heated water near the element be replaced by the surrounding water (mostly from below) causing mixing?
I'm in the middle of building a 60l electric HLT.... So I guess I'll find out soon enough.

Asher for now

 

[sluggerdog]

But, it's something that you cannot just set and forget. You will have to stir the water occasionally to prevent stratification as cooler water will sit underneath the heater. I stir mine every 10 or so minutes to get even heating

Is this true? wouldn't the heated water near the element be replaced by the surrounding water (mostly from below) causing mixing?
I'm in the middle of building a 60l electric HLT.... So I guess I'll find out soon enough.

Asher for now

[post="110406"][/post]​

I found this too, the water had cold parts and hot parts when the thermostat goes off, stiring is required.

 

[Pumpy]

I may need the electric drill and paint stirrer on the timer too

Pumpy

 

[Linz]

or a car's wiper motor....

 

[Darren]

I have used an immersion heater that doesn't reach to the bottom of my HLT (freebie) The water below the heater is stone cold and the water above almost boiling. I imagine making sure the heater is as low as possible would help. A pump timed to come on every ten minutes would be good too. Just need some time to get around to doing it.

cheers
Darren

 

[Kai]

Is this true? wouldn't the heated water near the element be replaced by the surrounding water (mostly from below) causing mixing?

Without agitation, hot water will always sit on top of cold because it's lower density. If your element is near the top then this will be an issue.

 

[Screwtop]

Yeah, watch it maybe even as much as .8 of a degree. Phaaaaaaarrrrrk!!!!

 

[mika]

Pumpy, just a thought and would mean a little longer to heat the water due to losses, but if you had a recirculating system (RIMS/HERMS) just switch the pump on at the same time you throw the heater element on.

 

[Asher]

Well it sounds like I'll be needing some sort of agitation. This new HLT I'm building will be timed. (check it out here). Although if its a set amount of water you could always just set the thermostat to a higher temp so when stirred just before doughing in you reach your desired temperature...

Asher for now

 

[kungy]

I have managed to get away with putting it down the bottom and to the side to get some convection currents happening fairly well. Its to the extent in the mornings that its fairly set and forget, but for the finer details like when close to strike temp or when taking temp measurements i give it a stir to equalise throughout.

Will

 

[warrenlw63]

I'll chuck a spanner in guys. Having experienced this on both sides.

Stratification seems to occur more if your HLT is uninsulated (don't ask me why). Long story short insulate it and the heating seems to become more even (probably due to heat retention I guess).

If it's uninsulated then you will probably gain more from some form of stirring device in the mix.

My HLT is well-insulated and also has a mechanical stirrer. Temp stays very even end of story. :beerbang:

A good idea is to plug your stirrer into a double adaptor with your thermostat. So when the element cycles on/off your stirrer does the same.

Warren -

 

[Batz]

My stirrer runs all the time the element is working.
Both start from a timer while I sleep , when I go down the brewery in the morning I have spot on mash-in temp. waiting.

Batz

 

[Screwtop]

My stirrer runs all the time the element is working.
Both start from a timer while I sleep , when I go down the brewery in the morning I have spot on mash-in temp. waiting.

Batz

[post="110664"][/post]​

Can's wait to see all this techo stuff today Batz!

 

[Pumpy]

My Hamster runs in his wheel all night long maybe io can connect the wheel with a pully to the stirrer in the kettle that may just be enough to circulate the water to avoid cold spots ,otherwise just when I thought hey I got a new imersion heater I need a fancy motor like Batz or Zwickle's for stirring .

Pumpy