Many years ago a term popped up in homebrewing which really should have never been introduced. Kettle Caramelization was first described in the Classic Beer Style Series book Scotch Ale by Greg Noonan. Here’s the rub, there can be no caramelization while water is present. If you boil wort for a long period of time you can get darkening and browning due to Maillard Reactions, but that is not caramelization so the term is bogus. Now I have taken the first runnings of wort off the mash tun and boiled them down to a candy stage and then added the rest of the wort to create a Scotch Ale and it was darn tasty, but I can assure you no brewery in their right mind would ever create a beer using that method. In that case I was caramelizing the sugars in the wort, and it probably could be called kettle caramelization, but just boiling wort is not caramelization and so the term has no basis in fact. Unfortunately it was picked up in the BJCP Style Guidelines many years ago and I have seen it repeated over the years. Just because something is repeated never makes it correct.
So what is caramelization, it is the browning which occurs with sugar and the earliest it can happen is 230F with Fructose. Here is a document from Minnesota State which details caramelization much better than I can. So if you hear someone say something about Kettle Caramelization in their beer you now know the person doesn’t know what they are talking about and unless they boiled that runnings down to the candy stage they had Maillard Reactions and not caramelization.
PS: The recipe for 80 shilling in the book is incorrect. It misses CaraPils which is in every other recipe. Don’t make it as it was published, trust me. You won’t end up with the right outcome. Not a bad result, just not a correct result.