I now dont use anything to smooth the spirit and allow grandfather time to do a little smoothing but as my skills have improved a lot since I started and the final product gets better and better with every batch. I just do a plain Ol sugar wash.
I have an LM fractioning reflux still and I end up with 95% every time. I discard 150ml of foreshots per 20L of wash just to be sure. I collect the next 14% as heads and the last 14% as tails and I still carbon filter after that only because I have access to as much top quality carbon as I want for free.
There is no hint at all of nasties in my bourbon and the first two batches I made without using glycerin or glucos have still made people shit the next day....evil evil bowl spraying sessions
So what on earth could be causing this!??
Cheers

