With a successful home made Special B from pale malt done, I am now doing some very small experiments with roasting pale malt to provide biscuit, chocolate and coffee malts. Having recently read research on the effect of temperature on crystal malts, I am interested in figuring out the different effects temperature and time will have on roasted malts and their flavours.
Experiment one, I decided set the oven to 145°C, and added 1/4 cup of pale malt. I was going to roast this until it was dark brown (+- 500EBC), however unlike the Special B, the colour change did not happen nearly as quickly as I would have liked. At 3 hours in the oven, I decided to call it a night. Initially the smell of the ground malt was like bread. However 5 days later, a newly ground portion smelt more like coffee.
Experiment two, the oven is set to 200°C, and again a 1/4 cup of pale malt is added. At 15 minutes the malt had reached the colour of the previous batch had at 3 hours at 145°C. A small amount was removed and ground up to compare, and another amount was stored for smell tests later. The rest stayed in for 1 hour, and resulted in a dark brown malt. The smell of both of these was harsher than the lower temperature roast, despite the colour of the 15 minute roast being the same.
A week after the doing the 200°C roast, I ground some samples again. At this point the 145°C roast had mellowed, it was very bready/biscuit in aroma. The two 200°C roasts still had decidedly burnt aromas, with the darker coming across as quite strong. The most surprising is the difference in smell between the almost identical looking lighter roasts. What effect this has on beer flavour will require further experimentation, something that will have to happen in the future.