argumate:

the British developed a taste for sherry after they sacked Cadiz and took thousands of barrels back home with them, so Spain ended up exporting a lot of sherry to Britain.

they didn’t want the empty casks back, and it wasn’t profitable to ship them there anyway, so the wily Scots took them and used them to mature whisky and get added color and flavour from the oak and the sherry.

but there’s a shortage of oak sherry casks now because they use stainless steel for export, and whisky keeps going up in price, so it’s actually cost effective for the distilleries to buy their own casks, lease them to the Spanish vineyards to mature sherry in for a couple of years, then take them back to use for whisky.

like so many human culinary tricks what started out as a lazy hack ends up being pursued as a goal in its own right.