Cold spots in an electric kettle

[Bugglz]

This is probably a dumb question, but for all you guys who have electric kettles, do you get cold areas under the element or does the rolling boil even everything out? I have a 2400w element in my HLT and have to recirculate the water in it to keep it at a constant temp as the water under the element doesn't heat up. I would imagine that the action of a rolling boil would mix the wort up and stop any cold areas for appearing, but as i plan to use a 2400w element in a (very well insulated) 50lt keg, I'm scared that the rolling boil won't be vigorous enough to properly mix the whole wort, resulting in an area at the bottom of the keg that isn't boiled/sterilised. Can anyone put my fears to rest?

 

[Nick JD]

There's no way a body of 100C water can remain unmixed.

 

[Fat Bastard]

Yeah, it's possible to get cold spots, but it'll mix just fine. I have a kettle that has the probe mounted at 90 degrees to the element, at the same level (a legacy from when I had a 1v recirculated BIAB system) and it generally shows 98.5 during a rolling boil. Boil-off is generally 12-14% which is ok, and judging by the movement of the hot break and hop pellets, it's mixing like all get out.

 

[Bugglz]

In that case it falls into the dumb question category , Cheers

 

[wessmith]

There's no way a body of 100C water can remain unmixed.

Sorry Nick, but yes it will. Water at 100C will not be boiling until you pump in the extra kilojoules to bring that water or wort to the boil, then you will get some vigorous mixing - and there will be no cold spots under the element. An HLT at 80C or 90C or even 100C will layer and as Bugglz has found, you need to recirculate to get an even temperature.

Wes

 

[Bugglz]

So basically as long as there is a rolling boil I'm safe. i was worried that the wort on top of the element would be 'rolling' and boiling while the wort in the area under the element wouldn't be completely mixed in.

 

[wessmith]

So basically as long as there is a rolling boil I'm safe. i was worried that the wort on top of the element would be 'rolling' and boiling while the wort in the area under the element wouldn't be completely mixed in.

Just make sure your definition of a rolling boil is not a gentle simmer and you will have no problems.

Wes