The congener of “ash” is parts of the “burnt” sub category as part of the “peaty” head category.
“Burnt” is a congener that is chemically linked to a lot of chemicals. For an overview one can look at this page on the “the goods cents company” website. This website does not have a “peaty” congener, but it does have one for “smoky”.
Both tar and soot are part of an incomplete combustion process of a fuel like, coal, coke or peat. The minaral left overs from the burning of these fuels are ashes.
The wikipedia site gives more detail into ash and can be found here. https://en.m.wikipedia.org/wiki/Ash
Quote: “Ashes as the end product of incomplete combustion will be mostly mineral, but usually still contain an amount of combustible organic or other oxidizable residues. The best-known type of ash is wood ash, as a product of wood combustion in campfires, fireplaces, etc. The darker the wood ashes, the higher the content of remaining charcoal will be due to incomplete combustion”
Since ash is the product of lots of burning processes there are lots of different compositions of ash. Think about your BBQ ashes, the ashes of a fire place.
A logical connection in the whisky production process is the fire that heats the kiln. M
Like the Laphroaig video says the material which is burnt is reduced to 3 inches of ash. This would explain the mentioning of ash on the Whisky Flavour Wheel.