Tasting the coffees that I roasted yesterday for my next class. We're doing brewed pots of coffee first because that's going to be safer for everybody and second because we're dealing with roasting plans for production roasts and most people don't drink their coffee one spoon at a time out of a cupping bowl.
The first flight is a basic roast level progression, and this is going to be an easy one for people to notice flavor differences. The third cup is a bit odd with sort of a bergamot-like flavor, but that's fine.
The 2nd flight might be the most difficult one for students. It's taking the lightest coffee from the first flight and doing two variations where the total time in the roaster is a minute less, but in one that's all front loaded where there isn't significant chemistry happening in the coffee and in the other it's divided proportionally through the entire roast so it looks the same in the percentage breakdowns.. There's a larger, but still subtle difference there.
(this is a practical example showing that DTR is a terrible metric that nobody should be using)
This kind of exercise usually shows differences primarily in the intensity and expression of sweetness in the coffee. While an inexperienced taster might not know how to describe the differences on this one, they should be easily able to discern that there are differences among all the coffees in this flight, though they're more similar to each other than the coffees in the first flight due to the similar roast level.
The fourth flight takes the darkest coffee from the first flight and adds variations where all the batches have the same total roasting time and match up to the start of first crack, but one goes faster through first crack and slower through second crack while the other goes slower through first crack and faster through second crack. Here again there are some clear differences in flavor.
For these very dark roasts, most students tend to prefer the roast that looks like an S curve (get the coffee hot enough to get your dark roast flavor characteristics fast enough that you're not overly diminishing flavors developed earlier) and I suspect that will continue to be true this time around.
The third flight takes the third coffee from the first flight and adds coffees that keep everything before the initial color change the same, everything after the coffee has turned brown the same, but goes faster or slower while the coffee is yellow in color.