Just want to add cement to the reason that you don't use cotton for your BIAB bag. If logic is correct.
On the weekend I did my first all grain brew with a cotton BIAB bag. When the bag got wet it would not let water through. This meant there was a layer of water that stayed outside if the bag. Every time I heated the mash the outside layer would boil, while the inside only slowly rose in temperature.
All completed I ended up with an efficiency of 58%. Not cool. It was also very hard to get the wort out of the bag. I'll get my wife to make one out of voile for next time.
On a side note. I had a bee hive move in next to the grains on my compost. Is this normal?
Edit: I was brewing Jamil's West Coast Blaster, by the way.