ABV Calculator

ABV is calculated by measuring the density change of your liquid before and after fermentation using a hydrometer or refractometer. The density is measured as Specific Gravity (SG).

The standard formula is:

For high-gravity ferments (over 1.090 OG like meads or heavy wines), the standard formula becomes less accurate. Our calculator automatically switches to the advanced high-gravity formula:

The 1/3 sugar break represents the point where yeast has consumed exactly one-third of the total sugar potential in your must.

In modern meadmaking and winemaking, this is a critical threshold. Aeration should stop after the 1/3 sugar break to avoid introducing oxygen into the fermenting must, which could cause off-flavors. It is also the final deadline for staggered nutrient additions (SNA), as yeast cannot safely assimilate nutrients past this point.

Brix is a measurement of the sugar concentration in an aqueous solution (grams of sugar per 100 grams of liquid).

For unfermented must, you can convert Brix directly using the gravity formula. However, once fermentation begins, the presence of alcohol (which is less dense than water) distorts refractometer readings.

Our advanced calculator uses the **Terrill Equation** to correct the reading when you provide the Original Brix. This ensures accurate gravity tracking even with a refractometer mid-ferment.

Hydrometers are calibrated at a specific target temperature (usually 60°F or 68°F). As liquid heats up, it expands and becomes less dense, causing the hydrometer to sink deeper and show a lower gravity reading than the actual density.

Conversely, cold liquid is denser and causes the hydrometer to float higher, reading artificially high. Our calculator uses standard density-temperature polynomial equations to normalize your readings back to your hydrometer's calibration temperature.

Louching (or the "Ouzo effect") is the spontaneous cloudiness or milkiness that occurs when water is added to certain spirits (such as anise-flavored liqueurs or gin). This happens because essential oils and botanical compounds are highly soluble in high-concentration alcohol but insoluble in water.

When the proof is cut below a certain threshold, these oils precipitate out of the alcohol solution and form a microemulsion that scatters light, giving the spirit a cloudy appearance.

High-quality spring water is widely preferred for proofing down spirits because it preserves natural minerals, improves mouthfeel, and avoids the flat taste of demineralized or distilled water (which can also leach minerals from the body over time).

When using spring water, it is best to choose a soft, low-mineral spring water. Heavy minerals like excess calcium, magnesium, or iron can react with botanical oils or barrel compounds, occasionally causing "mineral haze" (cloudiness). Using clean, low-mineral spring water gives you the perfect balance of clarity, health, and flavor.