I wouldn't call any peated malts THE core malt in any JW blend. JW's are not very peated blends (compared to the likes of Islay Mist and Black Bottle).
As mentioned, the peat component in these major blends changes over time. For Diageo, they have 3 distilleries producing peated whiskies. Caol Ila, Talisker and Lagavulin. As the latter two are smaller and very popular single malts, Caol Ila is the most probably peat part in Diageo's blend. It doesn't have to be these three. Around 2011 Caol Ila was being modernised and Diageo actually rented Bunnahabhain for nearly a year to produce peated malt. Just to keep up with future supplies for blends. When Caol Ila was rebuild in the early seventies, they made peated malt at Brora!
Yes :-)..and that peated Brora malt possibly is the most famous in the history of whisky.
Diageo had three distilleries on Islay and when whisky downtime hit in the 80's they didn't want to shut down the modern efficient one (Caol Ila)On another note, did they shut down Port Ellen because Caol Ila was so efficient? I wonder if we'd all be searching for old Caol Ilas if it had been shuttered back in the day.
This was before many drank single malts. When Port Ellen was operating it didnt have the same name as it has today when all stock is old and rare
I never tasted Caol Ila from before the total rebuild in the early seventies, but I would like to :-). Old Caol Ila. I am looking for that even with the distillery running. For some odd reason there are loads of bottlings out there aged 25-30, but 30+ is rare as a hens teeth, seen a few out the last couple of years though
Glenmorangie 10 is what kickstarted my passion for whisk(e)y.
On point with Diageo, it will be interesting to see if there is a shift in JW's profile in the coming years when Diageo's newest behemoth distillery, Roseisle, becomes one of the primary malts in the blend. Apparently, they can produce all the malts they need for all the JW blends at that one distillery.