Historical Supply Arrangements
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 buyers among Scottish distillers who discovered that wood previously holding sherry affected maturing spirit.
By the 1980s, this arrangement was changing. Spanish producers were adopting stainless steel over oak. 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 bodegas, past stacks of casks in solera systems, the team began documenting what sherry casks were and what made them useful for whisky maturation.
The visit revealed complexities the industry had not fully understood. The type of sherry mattered. The cooperage practices mattered. The oak species created differences in the final whisky character.
In the bodegas of Jerez, surrounded by centuries of tradition and the aroma of ageing wine, an investigation began that would develop understanding of wood maturation.
Quality Verification Challenges
Evidence emerged of questionable commercial practices. Since Victorian times, certain operators had found ways to make ordinary casks appear more valuable, charging premium prices for inferior wood.
As late as 2016, warnings circulated about dishonest practices in cask supply. Some schemes were sophisticated. Others were direct. These practices primarily affected naive or untrained distillers who lacked the expertise or relationships to verify what they were purchasing.
European Oak: A Different Chemistry
European oak contains higher levels of extractable phenolic compounds compared to American white oak. The chemical composition created 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 Supply Crisis to Methodology
The 1985 research in Jerez marked the beginning of an 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 objective was to transform a changing supply system into something sustainable, verifiable, and capable of delivering consistent quality.
Building Supplier Networks
Not all cooperages operated with the same standards. Finding partners who prioritised quality became important. These relationships, built through repeated visits, provided verification that regulations alone could not.
This approach would prove useful when advising new distilleries. How could a start-up operation secure genuine sherry casks? The answer lay in established relationships and direct oversight.