100% fermentable. Cleanest, no flavour impact.

~91% sugar by weight. Very clean and reliable.

~80% fermentable. Subtle character — great for mead and cider. Dissolve in warm water first.

~75% fermentable. Traditional for beer — won't dilute malt character.

~90–97% fermentable. Subtle flavour. Good in seasonal ales and ciders.

Ethanol and water form hydrogen bonds on mixing — the final volume will be ~2–3% less than the sum of the parts at high ABV. This is why the "verified ABV" tile exists — it accounts for arithmetic total, not physical contraction.

Distilled or RO water gives the cleanest result. Tap water with high mineral content can cause permanent hazing (chill haze or louching) in high-proof spirits.

ABV is measured at 20°C. If your spirit is cold or warm when you proof it, your hydrometer reading will be off — use the Gravity tab to correct it first.

Home distillation of spirits is illegal in the UK without a licence. This calculator is intended for proofing down wine, cider, and mead, or for legal distilling contexts (e.g. New Zealand).

Liquid below calibration temp is denser — hydrometer sits higher but reads lower. Corrected SG will be higher than measured.

Liquid above calibration temp is less dense — hydrometer sinks slightly. Corrected SG will be lower than measured.

At 30°C vs 20°C calibration the correction is ~0.002 SG — small, but relevant near the end of fermentation where FG precision affects ABV accuracy.

Chill sample to calibration temperature before measuring if possible — avoids the correction entirely and gives the most accurate reading.

Official rate: 1″/gallon for beer, 3″/gallon for spirits and wine. The honeycomb pattern dramatically increases surface area versus a plain stave, so these rates are lower than you'd use with plain oak.

Alcohol is a solvent — higher ABV pulls oak compounds faster. A spirit at 60% will extract the same flavour in roughly half the time of one at 40%. Dilute to barrel-entry strength (~63%) or lower before oaking for better control.

End-grain and honeycomb-format wood can produce astringency faster than a barrel stave. If you detect a bitter, drying finish, pull the stick immediately — this won't age out easily.

True barrel aging involves slow micro-oxygenation that alternatives can't fully replicate. Gently swirling or briefly uncapping your vessel daily introduces some oxygen and can improve results.

A used stick can be soaked in a different spirit (bourbon, sherry, rum) before re-use to impart layered flavour. Spent sticks contribute much less oak but can still add spirit character.