I used it both mash and boil again this weekend, first time in a long time using both doses (I'd used it in the mash again recently,) and I paid close attention. I can't of course say for sure what it did in the mash, but it didn't hurt, as far as I can tell. In the boil, it may well have enhanced the function of the Whirlfloc. Can't be certain, but maybe. So many other factors. At any rate, wort from the lauter tun and into the fermenter were both crystal clear. I can get that otherwise, but. How much BTB contributed I don't know, it doesn't seem to have hurt. I suppose the takeaway is that BTB is at most one part of a whole regime, not a magic ingredient that will by itself radically improve your process or your beer. But as long as I have some around I suppose I'll start tossing it in again. Thing is, I'll probably never know if it extends shelf life. My beer is fermented in a closed process, kegged, stays cold its whole life, and that life is short. But it's like yeast nutrient maybe. Cheap insurance you may not need.