Burnt Flavor in Pilsner Wort After Boil – Cause and Solution?

[Shahar]

A quick consultation—I’d appreciate some help before pitching the yeast.

I’m brewing with an eBIAB setup,
using a 13.2-gallon kettle (50 liters), no sparge,
based on BrewUno with a 3.5kW, 220V heating element.

I brewed a Pilsner that will serve as the base for a sour smoothie.
Mashed at 145°F (63°C) for an hour, with wort recirculation throughout the entire mash (60 min),
boiled for an hour.

Batch volume was 5.5 gallons (approx. 22–23 liters).

I brewed as usual yesterday, and toward the end of the boil, there was a slight burnt smell.

After emptying the kettle and transferring to the fermentation vessel, I noticed what looked like burnt sugar on the heating element—everything around it turned into black charcoal.

I’m using a grain basket, so the grains never touched the heating element at all.

Still, the burnt taste and smell carried over to the wort—not super strong, but noticeable.

What do you think could have caused this?
Should I pitch the yeast and hope the burnt taste and smell will somehow fade or be masked by the Philly Sour?

 

[doug293cz]

Everything I have read about burned/scorched wort flavors says they do not age out. So, the question is: how objectionable is the flavor, and do you think it is mild enough that souring will mask it adequately. If it's highly objectionable at end of boil, I'd recommend cutting your losses and dumping.

I'm not familiar with "BrewUno."

• Does it provide a way to control element power while heating to a boil, and during the boil, or is it run at full power for these steps?
• If it does control power for these steps, what percentage power did you use?
• Can you post a picture of your element, or give a manufacturer and part number, or link to supplier's listing? Too high a power density (watts/in^2 of element surface area) is a scorching risk.

How clear was the wort pre-boil? High levels of suspended particulates can result in some of the particulates settling on the element, which reduces heat transfer from the element to the wort, and raises the local surface temperature of the element, and this can lead to scorching. This is more likely to happen during the heat up to boil, as once you are boiling, there is a lot of convective mixing, which will minimize particulates settling on the element.

Brew on

 

[day_trippr]

"3.5kW, 220V heating element"

I wonder what the watt density might be for that element...

Cheers!

 

[Bobby_M]

Recirculated too fast, created an airspace at the bottom of the kettle, partial dry firing of the element (damp fire?). Slow the recirculation down a LOT more.

 

[Skeeter686]

Bobby's got a point. If that's what happened, then be happy you probably only need a cleaning (and maybe dumping that batch). I ended up having to buy a new heating element after my second or third brew day with my first electric system.

 

[Shahar]

Bobby's got a point. If that's what happened, then be happy you probably only need a cleaning (and maybe dumping that batch). I ended up having to buy a new heating element after my second or third brew day with my first electric system.

Thanks everyone!
I ended up dumping everything straight into the sink
Will try to recirculate slower next time.