Do not under-estimate the importance of technical layering. You can buy the best breathable motorcycle jacket, without the right underwear it will not work.
Always keep your body dry.
This is the job of technical layering. The base layer close to your body has to absorb your sweat and to push it outside. The mid layer such as a fleece jacket or a Softshell jacket has to keep you warm.
Stadler is using natural fibers such as Merino wool as well as the very moisture absorbing Nilit Breeze synthetic fiber. By hot weather the Nilit Breeze fiber offer you a very comfortable cooling effect. Merino wool has the advantage to be perfectly odorless even after a longer usage.
Synthetic fibers will absorb your body odor but are more efficient concerning sweat transportation.