Some help needed in England please. I have started doing 30 min mash and 30 min boil for my stove top BIAB and partial mash brews, purely for time saving, though I like the idea of more hops later, maybe I should do 20/20. It's early days and I'm struggling with IBU accuracy, I don't know how to calculate the effect of adding hops to the kettle after the mash, and 15-20 minutes before the boil is reached, and the period after the boil when the wort is above 80C/176F. I estimate this to be about 15 minutes - I cool in the kitchen sink. It's like isomerisation gets the full 60 minutes or so. My first 30/30 brew was much more bitter than planned, as isomerisation was presumably taking place before and after the boil. A 60 minute boil takes out most of the acids so didn't present this pre/post boil problem, to anything like the same extent.
I could add the first hops to the kettle at boiling point to solve that end of the equation. At the other end, should I time the period it takes me to get to 80C and add that time to the hop calculations? Because there is clearly still a fair amount of acid being converted. Thanks.