A few years ago I gave presentations at the CBC and AHA conventions, the basis of those lectures was around the Briess kilned Aromatic 20º L and Briess roasted Caramel 20º L malts to compare and contrast—how two malts of the same color can taste so radically different. It’s important to understand the differences and capabilities between a kiln and a roaster as they are definitely not designed to be interchangeable, one is not ‘better’ than the other just different.
A kiln has a very large footprint and is designed to do very large batches over a relatively long period of time (compared to a roaster). Similar in design to a hop kiln with a false bottom and a heat source below, a kiln typically has a maximum achievable temperature of 240F and can dry down batches over the course of 48-hours in some cases. And though a turning machine is run thru the bed multiple times, a kiln is somewhat inefficient and by design cannot have kernel uniformity—kernels closer to the heat source at the bottom will be darker than the ones towards the top. Lastly, kilns are not designed to retain moisture but to remove it for shelf stability while creating different colors and flavors at typically low Lovibond.
In contrast, a roaster has a relatively small footprint producing small batches over a much shorter period of time. With a rotating steel drum inside a housing, the roaster can apply heat directly to the drum or to the gap between the drum and the housing. These temperatures can be upwards of 750F and can produce specialty malts in typically 2-4 hours per batch—with these extreme temperatures we can achieve very high colors upwards of 550L. As you would expect the roaster is highly efficient and produces a very uniform kernel as the drum rotates between 20-30rmp while heat is applied. Though like a kiln the final outcome is to dry down to a shelf stable product, the roaster can be adjusted, by closing the vents to retain moisture depending on the need for whatever product is being made.
So, all that said we arrive at our Aromatic Munich Malt 20L, which is made on a kiln, and our Caramel Malt 20L that was produced in a roaster. You can see the pictures at the top of this blog that they look radically different. The Aromatic is 100% mealy (white, chalky, starch) and has been dried down to preserve enzyme activity—in this case, 20 DP. In contrast, the Caramel 20L is 100% glassy due to the kernels ramping thru a similar temperature profile as you’d have in your mash tun to convert starches to sugars and caramelize them inside each kernel. As expected, caramel malts are not designed for enzyme activity, there is none, but to drive more intense flavors and colors. So, while the color of both malts hits 20L in the lab that’s where the similarities stop as the flavors are crazy different. The Aromatic Munich 20L is a clean, slightly sweet, intense malty punch in the face while the Caramel 20L has a candy-like sweetness with a light caramel flavor. Both delicious just different!
If you’re interested to see some further information on the difference between a kilned caramel malt versus a roasted caramel malt and their production you can check out Bob Hansen’s blog, Is it Crystal or Caramel Malt?