1. What is Beer Attenuation?

Apparent attenuation (AA) measures the percentage of sugars that have been converted to alcohol and CO2 during fermentation. It's a key indicator of fermentation efficiency and yeast performance in beer brewing.

2. How Does the Calculator Work?

The calculator uses the apparent attenuation formula:

Where:

• \( OG \) — Original gravity (before fermentation)
• \( FG \) — Final gravity (after fermentation)

Explanation: The equation compares the drop in specific gravity (sugar content) to the theoretical maximum possible attenuation.

3. Importance of Attenuation in Brewing

Details: Attenuation affects beer's alcohol content, body, and sweetness. Different yeast strains have characteristic attenuation ranges that influence beer style and flavor profile.

4. Using the Calculator

Tips: Enter original and final gravity as measured by your hydrometer or refractometer. OG must be greater than FG, and both values must be greater than 1.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical attenuation range?
A: Most ale yeasts attenuate 65-80%, while lager yeasts typically reach 70-85%. Some high-attenuation strains can exceed 90%.

Q2: How does this differ from real attenuation?
A: Apparent attenuation doesn't account for alcohol's effect on specific gravity. Real attenuation is about 20% lower but requires more complex measurement.

Q3: What affects attenuation?
A: Yeast strain health, fermentation temperature, wort composition (fermentable sugars), oxygen levels, and nutrient availability.

Q4: My attenuation seems low - what's wrong?
A: Possible issues include incomplete fermentation, poor yeast health, insufficient oxygen, or too many unfermentable sugars in the wort.

Q5: Can attenuation be too high?
A: Excessive attenuation can create thin, dry beers. Some styles (like dry stouts) benefit from this, while others (like malty ales) don't.