Let’s say a recipe calls for 2 ounces of Cascade hops at 6% Alpha Acids, but the hops you have are listed at 8% alpha acids. It seems like you should adjust, but how much? That is what this calculator is for.
Also be sure to check out our Homebrew Hops Database that lists 175 hop varieties and their best substitutes.
Important notes for homebrewers
- This keeps the total alpha acids (and thus the approximate bitterness contribution) the same, assuming the same boil time, hop form (pellets vs. whole), and other conditions so utilization stays comparable.
- It works best for bittering additions (longer boils). For late flavor/aroma additions or dry hops, matching the sensory/oil profile matters more than exact AA% matching—the formula alone won’t replicate flavor.
- Always use the actual AA% printed on your hop package, as it varies by crop year, growing conditions, and storage.
- For greater precision (especially if boil times, gravity, or hop form differ), plug the numbers into a full IBU calculator (Tinseth, Rager, etc.) rather than relying solely on AAU matching.
- Small differences often don’t matter much in practice for homebrewing, but larger gaps in AA% (or cohumulone content) can noticeably change bitterness intensity or character.
This simple proportional adjustment is the method recommended for keeping bitterness on target when substituting hops.
Hop Alpha Acid Substitution Calculator
Adjust hop weights to keep the same alpha acid contribution when substituting hops with different AA%.
- Best for bittering additions (same boil time and hop form).
- Use the actual AA% printed on your hop package.
- For late/aroma additions or dry hops, flavor profile matters more than exact AA matching.
- This preserves total alpha acids. For precise IBUs when boil times, gravity, or hop form change, use a full IBU calculator (Tinseth, Rager, etc.).
Disclaimer: This calculator adjusts hop weight to match total alpha acids. It is an approximation intended for bittering additions under similar boil conditions. Actual bitterness (IBUs) can vary due to hop form, utilization, cohumulone levels, hop age, and brewing process. Always taste and adjust recipes as needed. Results are for informational purposes only.