Vinegar Mother Calculator

Calculate expected acetic acid percentage and fermentation time for homemade vinegar. Factor in starting ABV, mother size, vessel volume, and temperature.

Inputs

Starting ABV (%)

Mother Weight (g)

Vessel Volume (mL)

Temperature (°F)

Tab to move between fields

Results

Expected Acetic Acid

5.7%

Days to Finish30 days

Weeks to Finish4.3 weeks

Optimal Temperature77–86°F (25–30°C)

How to Use This Calculator

Enter the starting ABV percentage of the liquid you are converting to vinegar.
Set the weight of mother (acetobacter culture) in grams and total vessel volume in mL.
Enter fermentation temperature in °F.
The calculator shows expected acetic acid percentage, days and weeks to finish, and optimal temperature range.
Cover the vessel with breathable cloth, maintain temperature, and taste regularly starting at the predicted finish date.

How the result changes with Starting ABV (%)

Starting ABV (%)	Expected Acetic Acid
2.4	2.28%
5.9	5.61%
10	9.5%
14	13.3%

What each input means

Starting ABV (%): Alcohol by volume of the starting liquid (wine, cider, etc.). 5–7% is ideal.
Mother Weight (g): Weight of the vinegar mother (SCOBY). Larger mother = faster fermentation.
Vessel Volume (mL): Total volume of the fermentation vessel.
Temperature (°F): Ambient temperature. Optimal range is 77–86°F (25–30°C) for acetobacter activity.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Starting ABV (%) = 6, Mother Weight (g) = 50, Vessel Volume (mL) = 1000, Temperature (°F) = 75 = 4 input(s) provided
Calculate Expected Acetic Acid
5.7 = 5.7
Calculate Days to Finish
Days to Finish
30 = 30
Calculate Weeks to Finish
Weeks to Finish = round((daysToFinish / 7) * 10) / 10
4.3 = 4.3

Engine last updated July 28, 2026. Checked against 2 independently-derived tests — how we verify calculators.

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