Induction hob / time to strike

[stubrewworx]

Hi all,

I'm hoping to return to brewing in the new year and thought I'd test my 30l pot on the home induction hob. 1, to test the fit and if it works; 2, to time how long it takes to reach strike temperature.

1, it works. It is a neff 2 hob with the option to consolidate the hobs to one large with around 3kw output.
2, it will have taken around 1 hour to get to strike temperature. I stopped at 65c @ 50mins. That was from around 20c.

I have previously used a 2kw portable induction hob but the last time I used it, it took approx. 35mins to get to strike temp from around 50c (from the home combi boiler), and if my notes are correct, 50min from mash to boil!

I expected the home hob to perform better, but it doesnt look like it will and I dont want to stress it on a 60min boil, so it looks like I have to stick with the 2kw portable and endure the times.

Does anyone else use induction but achieve better heating times than I?

 

[kelper]

How much water are you heating? Do you have a way to measure the actual current or power? (such as a Kill-a-Watt plug-in power meter)

I use an induction hob for boiling dried elderberries or frozen fruit when I make wine but have not timed it.

HERE is an online calculator which tells you how much power is needed to heat water through a given temperature range in a given time. It does not allow for losses but should give an idea of times.

30 litres from 20°C to 65°C in 50 minutes is about 1.88kW so with losses perhaps 2kW

 

[stubrewworx]

I should add, I'm talking about 25l of water and the boil on the 2kw portable is very very light.

 

[umfana]

I should add, I'm talking about 25l of water and the boil on the 2kw portable is very very light.

To me this suggests that the ferrous inserts on the bottom of your pot that make it induction compatible are not so large so the pot is not picking up much inductive power. There is no way 2kW should be a light boil on 25L. Unless you are brewing inside a freezer.
My modified urn is only 900W and manages a full boil (almost too much) with 30L.

I've had this problem with my crepe pans. One is very good on the induction. The other not so much.

Have you go anything like a le creuset cast iron pot that you can do a test boil of water volume from? Eg same volume of water in the cast iron as in your brew pot and test time to boil?

 

[stubrewworx]

HERE is an online calculator which tells you how much power is needed to heat water through a given temperature range in a given time. It does not allow for losses but should give an idea of times.

30 litres from 20°C to 65°C in 50 minutes is about 1.88kW so with losses perhaps 2kW

Thanks for that, so my timings are about right.

 

[stubrewworx]

Have you go anything like a le creuset cast iron pot that you can do a test boil of water volume from? Eg same volume of water in the cast iron as in your brew pot and test time to boil?

Yeah thought about doing that to check if its the pot, cheers

 

[kelper]

Thanks for that, so my timings are about right.

Not really. You said your hob was 3kW but it behaves like a 2kW. Did you use the calculator I linked to?

 

[stubrewworx]

Not really. You said your hob was 3kW but it behaves like a 2kW. Did you use the calculator I linked to?

Ah yeah, the home/kitchen hob but tbh the 3kw 'merged' figure i got was from the internet, nothing in the actual paperwork, I thought it was a hopeful output.

But the 2kw portable is about there.... unfortunately. I was just checking if it was 'normal'.

Looks like I have to endure the heat up times.

I'll just try all the usual methods, using water from the home boiler, thermal wrap on the pot etc.

Cheers,

 

[Drunkula]

I can check the inductive coupling with the energy meter. Because of the nonsense I'm doing you notice that it drops a couple of hundred whats when the steel lid I'm using as a heating element is moved about a cm away from the induction plate because of the ridge bottom of the one fermenter I use as a boiler.

I get too much of a boil at 1500 watts with 26 litres.

 

[stubrewworx]

How much water are you heating? Do you have a way to measure the actual current or power? (such as a Kill-a-Watt plug-in power meter)

The kill a watt look interesting. Are the £10 ebay ones any good?

 

[kelper]

The kill a watt look interesting. Are the £10 ebay ones any good?

no