I do BIAB and in my constant search for ways to simplify my brew day I recently started to heat my mash with the grains already in. That is:
- I fill my kettle with the full water volume I'll be using (~27L). Water is about 10C this time of the year.
- I dough the bagged grains in. The bag is bound by a string and kept slightly off the bottom of the kettle.
- I apply heat until I reach my mash temperature, mixing the grains every now and again, turn off the heat and wait 90 minutes (I'm sure the conversion happens way before that, but I give it 90 minutes anyway).
- I mash out, remove the grains and proceed to the boil.
This process allow me to more precisely control the mash temperature (heating the water above the mash temperature and adding the grains has always given me mixed results).
Given that enzymes are denatured when a certain temperature is reached, my mash goes through all the 'rests' until reaching the starch conversion rest at my target mash temperature. The heating process take around 30-40 min.
Any drawbacks in doing this?