difference in brew day length between 4500w and 5500w

[NoCornOrRice]

So I can get a 4500w 240v element locally for 1/4 the price of the cheapest 5500w one by the time you factor in shipping. I have an as-of-yet uninsulated sanke keggle, and ambient room temp of about 70F at the start of the brew day.

Any ideas how much faster the 5500w one would be? The MLT and HLT are insulated.

batch size is 10gal

water temp is about 48F if I use cold water, or 131F from the hotwater tank, I usually use already hot water.

 

[lzrdkng14]

not sure on this, but one thing I can add is that using hot water is typically a bad idea. there are deposits on the bottom of the hot water heater that can contaminate your brew...stick with the cold water - its cleaner

 

[passedpawn]

Any ideas how much faster the 5500w one would be?

4500/5500 faster

i.e., it takes me 20 minutes to heat up my strike water. with a 4500W element, it would take 5500/4500 * 20 minutes or 24 minutes. Not enough to worry about.

 

[DeafSmith]

4500/5500 faster

i.e., it takes me 20 minutes to heat up my strike water. with a 4500W element, it would take 5500/4500 * 20 minutes or 24 minutes. Not enough to worry about.

It's a little more complicated than that. You really have to know how much heat is being lost from the kettle. For example, if heat loss is 1 kW, then with the 4500 watt element you have 3500 watts net heat into the water, but with the 5500 watt element you have 4500 watts into the water. So the time to heat with the 5500 watt element is really 35/45 of the time to heat with the 4500 watt element, not 45/55. Not much difference here, but what if heat loss is really 2 kW? Then it's 25/35, and starting to get significant. If you know the net heat into the water, of course you can calculate how long it would take to heat x pounds of water by y degrees F. x times y is the required number of BTU and 1 kW = 3412 BTU/hour. Also 1 gallon of water at room temp. weighs about 8.33 pounds and 1 gallon at boiling is approx. 8 pounds. Plug in your numbers and do the math.

 

[Cpt_Kirks]

It takes me about 28 minutes to heat my strike water for a 10 gallon batch.

That is using an uninsulated keggle as HLT, with 4000 watts of heating power.