Like the last bourbon I just reviewed, Old Grand-Dad is made at Jim Beam and is branded as one of "The Olds" with Old Overholt. I believe this recipe has more rye content than standard Jim Beam. Thanks to @Nozinan for the sample.
The colour is a medium copper. Quite fruity on the nose with pineapple and papaya. There is some toasted oak but not that much - I have a feeling this is pretty young whiskey. It's somewhat mentholated, like Vicks, which I find a little off-putting. Cigarette ash. Bitter dark chocolate. Very herbal and floral (less so with water), this really does strike me as not having as much time in oak as maybe it should have.
A bit more anchored on the palate, with more spices - pepper, rye and cloves - and a nice backbone of soft caramel. Not too sweet. The menthol and herbs that I found overpowering on the nose are here, but not so upfront. A drop of water adds sour cherries and puff pastry. Interesting, but still tastes too young.
The finish is soft with toasted oak and a nice umami note, then develops into mint and cotton candy. For me, this is more interesting than it is fully successful. That strong medicinal nose spanked me just a bit too hard, then before I could utter the safe word it pulled back and redeemed itself with some nice spices and baking notes. Overall, I like it fine but I think it should have been strapped into the barrel just a little longer.
I will say, I let it sit for an hour or so and the "Vicks" note calmed down - but it didn't calm down enough for me. I would still rank it lower than both the 114 and the standard.
: Light and airy nose for bourbon. Definitely rye bread. It says "high rye mashbill," if anyone knows the specific numbers I would be interested. I suppose I could google... anyway. Rye bread, cane sugar, pecans. Light, sweet, nutty. 
@Nozinan Yes, at first I wondered if there was something up with the sample bottle, or even my glass - that big menthol / eucalyptus note was not what I remembered from the 114 (though in that review I do mention a lot of herbal notes). Reading my old review of the 114, I also call it "...bourbon that can slap you silly like your grandpappy might..." Clearly I have a theme running through all of these. And clearly I need deep, deep therapy.