Advanced Alpha Acid Calculator
Advanced Alpha Acid Calculator
Use this tool when:
- You run out of hops half way through weighing and your next packet has a different alpha acid.
- You want to modify a recipe to use a mix of hop varieties.
For a single hop substitution, use the simple Alpha Acid Calculator.
Examples
Example 1 — Running out of hops
Scenario
A recipe calls for 35g of Challenger hops at 7.6% alpha acid.
Using a packet of Challenger at 7.9% alpha acid you begin to weigh out the hops. The packet runs out and the scale only reads 25g.
You reach for your spare packet of Challengers to find that their alpha acid is considerably higher, at 8.7%. So how much extra should we use?
Solution
Enter 7.6 and 35 as the original alpha acid and weight.
Click + Add new hop to add a second replacement row.
Enter 7.9 and 25 for the part-packet you already weighed, then 8.7 as the alpha acid of the new packet.
Click Calculate — the last weight fills in automatically.
Result
You need just short of 8g from the new packet to achieve the same bitterness as the original recipe.
Example 2 — Replacing with a different variety
Scenario
A recipe calls for 13g of Target at 11.4%, 7g of Challenger at 7.6% and 7g of Northdown at 8.3% alpha acid.
You want to keep the bitterness level but replace the Target and Challenger entirely with Styrian Goldings (at 5% alpha acid), leaving the Northdown as-is.
Solution
Enter 11.4 and 13 as the first original hop (Target).
Click + Add original hop and enter 7.6 and 7 for the Challenger.
Enter 5 as the replacement alpha acid (Styrian Goldings).
Click Calculate.
Result
You need a fraction over 40g of Styrian Goldings to make up for the bitterness of the Target and Challenger.
Example 3 — 50/50 split between varieties
Scenario
A recipe calls for 2oz of Hallertauer Hersbrucker at 4.9%.
You have Tettnang at 2.3% and would like to try a 50/50 split between it and the Hersbrucker (which you also have at 4.9%).
With two different alpha acids, how much of each do you need to achieve the same bitterness?
Solution
Enter 4.9 and 2 as the original alpha acid and weight.
Click + Add new hop to add a second replacement row.
Enter 4.9 as the first replacement alpha acid (Hersbrucker) and enter 2.3 as the second (Tettnang).
Since you want equal weights, enter the same weight for the Hersbrucker row — the calculator will work out the Tettnang weight from what remains.
Click Calculate.
Result
You need 1.4oz of each to achieve the same bitterness as the original recipe.
Note: In this example we used ounces. It does not matter which unit you use so long as it is consistent.