--deleted. wrong thread. --
OK, here's what I meant to write. This damn cold is not helping the thought processes.
Should it be a clearer line though? Is it because of all the "stuff" in there? I'm pretty sure my APA wasn't that fuzzy.
...I was having thermometer issues and it was my first BIAB.
Ditto, nice images. They could be used for teaching.
I also notice fuzziness while reading the wort and the final fermented wort. It is probably because there are many compounds in there with different refractive indexes. It was not as fuzzy when I made a low alcohol beer, again probably because there was less stuff in there.
Temperature fluctuations with BIAB - I have also had problems chasing the proper mash temperature and have not entirely resolved it. Perhaps this info will help.
I think it is because of the method of reading temperature and not that the mash temp changes so quickly. I find the glass thermometer reads more consistently when the cold grain is stirred in thoroughly, the thermometer is inserted into the center, and I leave the pot covered for a few minutes. Then I uncover the pot and read the temperature very quickly. I was surprised how much temperature variation there is from top to bottom of the grain and how quickly the top grain cooled off when the lid was removed. Also, how fast the thermometer cooled off when it was removed for a reading.
For my next BIAB batch I will add the grain at the calculated strike temperature, stir it well, insert the thermometer, cover it, and
leave it the heck alone for 5 minutes. Then pull and read the thermometer quickly.
BIAB is usually done in an uninsulated pot instead of a nice, cozy mash tun. If you use the full 7 gallons for a 5 gallon batch, the large heat mass will better maintain temperatures.