BIAB Disadvantages to go with the Advantages thread.

[doug293cz]

So risk of leaving bag in is scorching, I assume. Or is there something else to consider? Does grain or bag really get scorched at 145-160 degrees?

Pretty sure my bag is off the bottom of my kettle, if I wanted to try this.

Guess I am getting at stepping at full volume, and just heating the kettle. Anyone doing or tried this?

The grain bag sitting on the bottom of the BK (in a propane fired system) or on the heating element (electric fired system) severely limits heat transfer away from the heat source. This causes local temps to be much higher than average temps, and this can lead to scorching.

Brew on

 

[Gruel]

So the one time I have done this, I had my sparging/lautering copper manifold at the bottom of the kettle. The bag might still have touched the bottom of the kettle between the coils of the manifold. The only partial melting/hardening of the bag that occurred on my gas powered range was around the edges of the kettle where I had draped the bag over it (which is pretty messy to begin with, and not recommended). I ran a 15,000 BTU burner at the medium setting, with an aluminum foil heat spreader below the kettle (the aluminum foil - folded - will disintegrate; I now switched to a more solid aluminum sheet; of course a kettle with a sandwich bottom would be best). So, I think you can heat the mash kettle with the bag inside.

Note that at full power I can produce scorch marks of burnt starch (I assume) on the inside of the thin walled steel kettle.