My GF is originally from Jackson area of MI (bit crazy we met in SoCal) and her favorite childhood soda pop was Faygo Rock n Rye. Faygo doesn't generally travel far outside of MI so not many people have had it and the flavor is rather indescribable - you've either had it or you haven't.
I turns out that the flavor is meant to ape the liquor Rock n Rye - which is basically rye whisky with some rock candy added and allowed to sit until mostly dissolved.
I've been enjoying the Bulleit bourbon and decided to give their rye a try. Its quite good. But last month while browsing the BevMO! I spotted a few bottles of Faygo Rock n Rye, and they had the Bulleit rye whiskey. I simply had to do the experiment.
Grabbed a new bottle of Bulleit rye, a couple bottles of Rock n Rye Faygo (which delighted GF), scored some rock candy, and went to work at home.
Opened the rye, poured a generous shot and employed it in the normal way, then replaced the volume in the bottle with chunks of rock candy (about 4-5 oz by weight I think). Corked it, and put it in the cabinet under the bar and left it to sit for a couple weeks.
When I retrieved the bottle most of the rocks were gone and the bottle had a color gradient running from dark amber at the top to nearly clear down around the rocks. Upending it a couple times to mix gently resulted in some very cool visual effects as layers did some cool refractory dances.
So then I poured a shot and tried it - the sweetness was just right, totally killed the burn and really brought the flavor of the rye forward - that yummy rye note from a well done deli sandwich was totally there. I then cracked the Faygo and compared - and it was surprisingly similar. Not the same - no alcohol for instance, but I finally understood what would have lead the Faygo brothers to call that flavor Rock n Rye. And the sweetened Bulleit has become a favorite bedtime nite cap.