First attempted at step mash - Scorch and fail!

[NotSure]

I tried my first attempt at a step mash today with BIAB and an Electric Kettle. I was aiming to make a Czech Pilsner and used the following mash schedule:
15 minutes @ 40°C (104°F)
15 minutes @ 50°C (122°F)
20 minutes @ 63°C (145°F)
20 minutes @ 70°C (158°F)
15 minutes @ 77°C (171°F)

After I was done letting the bag drip, I started stirring before turning the heating elements on. I noticed from feeling with my spoon that the elements felt "crunchy". So, I drained the wort into a couple buckets and found my elements were totally scorched. The wort was also tasting slightly burnt too, so I dumped it. This is the first time I've scorched wort prior to the boil.

On the bright side, I only wasted some time, malt and bottled water. Somehow I also managed to get close to a 100% Conversion Efficiency, which was nice, but wasted in the end.

My guesses as to why it scorched would be (1) not enough circulation around the element, (2) a lot of flour in my malt, (3) an old brewbag that has lots of small holes, and (4) a delay in starch conversion due to the step mashing.

I re-ordered the malt from the brewshop and am going to try again in a few days with a single-step infusion and new brewbag.

Am I missing any other possible reasons for the scorching?

 

[augiedoggy]

what is the wattage of that element? is it a ULWD element? It doesnt look like it. your right in guessing you need good flow around the element.

 

[NotSure]

what is the wattage of that element? is it a ULWD element? It doesnt look like it. your right in guessing you need good flow around the element.

I have two elements at 2.4kw. I don't know if they're ULWD, so I'm guessing not.

 

[augiedoggy]

I have two elements at 2.4kw. I don't know if they're ULWD, so I'm guessing not.

With the amount of surface area vs wattage, from the pictures Id say they are definitely not. the more actual heating element vs heat wattage means you get a lower "watt density" on the heating surface and gentler heating action... its kind of like the different between using a cheap pot with a paperthin bottom vs a triclad copper bottom pot to cook something. your less likely to have stuff burn to the bottom of the larger more evenly distributed heated surface of the better pot. ULWD elements are like the better pots and pans in this case.

 

[NotSure]

With the amount of surface area vs wattage, from the pictures Id say they are definitely not. the more actual heating element vs heat wattage means you get a lower "watt density" on the heating surface and gentler heating action... its kind of like the different between using a cheap pot with a paperthin bottom vs a triclad copper bottom pot to cook something. your less likely to have stuff burn to the bottom of the larger more evenly distributed heated surface of the better pot. ULWD elements are like the better pots and pans in this case.

Thanks for the info. If I give doing a step mash another try, I'll see if I can upgrade my kettle with ULWD elements first.