The Perfect Maturation Cask?
For over a century, the relationship between sherry and Scotch whisky appeared stable. Spanish bodegas shipped their solera matured wines to Britain in oak casks. Once emptied, these casks found eager buyers among Scottish distillers who discovered that wood previously holding sherry created something exceptional in maturing spirit.
By the 1980s, this arrangement was unravelling. Spanish producers were abandoning oak for stainless steel. New regulations mandated bottling at source. The transport cask trade that had sustained the industry for generations was ending.
Spring 1985: Journey to Andalusia
A research delegation travelled to Jerez. Walking through ancient bodegas, past towering stacks of casks in solera systems, the team began documenting what sherry casks actually were and what made them valuable for whisky maturation.
The visit revealed complexities the industry had never fully understood. The type of sherry mattered. The cooperage practices mattered. Even the oak species created profound differences in the final whisky character.
In the bodegas of Jerez, surrounded by centuries of tradition and the rich aroma of ageing wine, a systematic investigation began that would change how the industry understood wood maturation.
The Problem That Wouldn't Go Away
Evidence emerged of a darker reality. Since Victorian times, certain operators had found profitable shortcuts: ways to make ordinary casks appear special, to charge premium prices for inferior wood.
As late as 2016, stern warnings circulated about dishonest practices. Some schemes were sophisticated. Others were brazen. All exploited the same vulnerability: distillers' difficulty in verifying what they were actually buying.
European Oak: A Different Chemistry
European oak contained significantly higher levels of extractable phenolic compounds compared to American white oak. The chemical composition created markedly different flavour profiles.
For generations, the industry had referred to "sherry casks" and "Spanish oak" interchangeably. Not until the early 1990s did reliable methods exist for distinguishing American from European oak in finished casks.
From Crisis to Methodology
The 1985 research in Jerez marked the beginning of a long-term investigation. Over subsequent years, the team visited Spanish and Portuguese bodegas repeatedly, building relationships with cooperages and analysing how different fortified wine styles influenced oak chemistry.
The challenge was clear: transform a collapsing supply system into something sustainable, verifiable, and capable of delivering consistent quality.
Building Trust Networks
Not all cooperages operated with the same standards. Finding partners who prioritised quality over volume became essential. These relationships, built through repeated visits, provided something regulations alone could not: verification.
This approach would prove especially important when advising new distilleries. How could a start-up operation secure genuine sherry casks? The answer lay in personal relationships and direct oversight.