Updated April 2026.
“On the rocks” is ice in the glass, not a TTB class. Bourbon still must meet and the 80-proof floor. A 1.5-ounce 40% pour is one NIAAA drink before melt; at 45% it is 1.13. Ice dilutes proof as it melts — it does not change how much ethanol you poured. This is not a 2022 top-15 tasting.
Higher-proof bottles hold up longer in the glass. Related: should whiskey be chilled, sipping bourbon, barrel proof.
Rocks vs neat math
| Pour | Ethanol poured | After ice |
|---|---|---|
| 1.5 oz 40% | 1.00 drink | Same ethanol, lower proof |
| 1.5 oz 45% | 1.13 | Same ethanol, lower proof |
| 1.5 oz 50% bonded | 1.25 | Same ethanol, lower proof |
Four 90-proof rocks pours are still about 4.5 drinks. NIAAA binge pattern is a health line, not a target. No 2026 MSRP. Pour math: whiskey drinks.
Sources
- TTB 27 CFR 5.143. NIAAA (December 2025). No invented ranking. Ice melt is physics, not a brand spec.