What Are STR Casks?

The world of whisky is constantly evolving, with new techniques and approaches emerging all the time. One such technique is the STR (Shaved-Toasted-Recharred), which was developed by our first master distiller and good friend, the late Dr. Jim Swan, a renowned whisky consultant, and expert. Dr. Swan was a pioneer in the field of whisky in general and hot climate maturation in particular, and his contribution to the industry has been immeasurable. He was known for his innovative approach to whisky-making, and the STR technique is just one example of his forward-thinking ideas.

As part of the STR technique, the inside of ex-red wine casks is first shaved, removing a thin layer and exposing a surface of fresh wood, while also ridding it from acidic wine sediments. A heating element is then introduced to toast the oak, making natural flavor compounds in the wood more readily available. Finally, the shaving a thin layer from the inside of the cask to remove unwanted flavors. The cask is then re-charred with fire, creating a new layer of active charcoal which reduces congeners in the whisky, which is also cracked in a “crocodile skin” pattern which allows for better interaction between the spirit and the oak, effectively expediting and enhancing the maturation process.

At the M&H distillery, we make wide use of STR casks in a variety of our products. However, the character of these casks tends to be quite intense, with robust aromas and powerful flavors. And so, by means of achieving a balanced flavor profile, we typically use STR casks as a secondary component in our core range of whisky blends, limiting them to up to 25% of the blend. Nevertheless, there are occasions when we come across STR casks that have matured to perfection and truly stand out, and in those cases, we choose to bottle them as single casks or include them in our APEX series.
Check out our Apex Sereis here >>