Low Watt Density heating elements - what density can be assumed safe for heating wort?

[eltomek]

I am in the process of designing my eBIAB kettle based on 50L (13 gallon) stainless steel 40x40cm (15x15") pot and am looking for a good heating element (of approx. 3000).

I have read about many element advertised as Low Watt Density but for some of them they were claimed to scorch the wort.
Looking at https://www.amazon.com/Dernord-Foldback-Heater-Element-Density/dp/B018S4AP5Y/ref=sr_1_7 assuming it has 8,5mm pipe diameter, it's density is 10W/cm2 or 25W/sq.inch (@1500W).

This one https://www.clawhammersupply.com/collections/all-products/products/1650-watt-element seems to have 7,5W/cm2 (19W/sq.inch) @1650W

Of course I am looking for larger ones but wonder if these 10W/cm2 isn't too much and will not end up scorching the recirculated wort (the mash itself will be in a basket).

 

[Staticsouls]

I use dernold 1650w elements and have two in my bk. I had to scale back from their 2000w elements, which are not lwd. I haven't experienced issues with scorching with either of these unless I turned the element off and let the trub settle and then turned it back on.

 

[FloppyKnockers]

I use some RV water heater elements that claim to be ULWD, but some reviewers said they aren't. Reports saying they scorch, don't last long, aren't LWD, etc. They have served me well for over a couple hundred brews. The secret is to clean your elements between brews to prevent scorching. Just run a scotch brite pad in and around them to remove the crud while cleaning the kettle and they will last you a long time.

2 - 120v 1500w Camco elements if you care.

 

[Staticsouls]

I also wipe down my elements after each brew.

 

[mabrungard]

I found that watt density is not a huge issue when your system has some sort of power modulation such as pulse-width. The only time I run my kettle element at full power is during the initial warm up to boiling. But using the lowest watt density available is a good goal.

 

[bstacy1974]

I used two 2000 watt high density elements in my BK for a few years. I had one scorching incident but it was my fault. Other than that, no other issues. Just upgraded to a 240v circuit with a 5500 watt element from Lowes. I'm in no way worried about scorching. Along with power modulation, consistent circulation is critical.