Pickling minimum
Tested canning recipes assume vinegar of at least 5% acetic acid.
Vinegar · Calculator
Vinegar Acidity Calculator
Turn a titration reading into percent acidity, predict how strong your vinegar will get, or dilute it to 5% for pickling.
Live calculator · updates as you type
Your vinegar
What do you want to work out?The test solution is the sodium hydroxide in a wine acid test kit; its strength is printed on the bottle, usually 0.2 N. Dilute 2 mL of vinegar in about 20 mL of distilled water, add a few drops of the indicator, then add test solution until the colour stays pink for 30 seconds.
Result
Acidity (as acetic acid) 4.98%
Label acidity50 grain
Acetic acid per litre50 g/L
Use Table strength; not strong enough for canning recipes
What to do next
What to do with this result
From your titration test.
Free printable
Keep this batch on one page
A batch card made from your numbers, to save as a PDF or receive by email:
- Your result in big type
- These steps with tick-boxes
- Dates to fill in
- An acidity log for each test
Titration readings: 2 mL vinegar sample, 0.2 N sodium hydroxide
| NaOH used | Acidity | Use |
|---|---|---|
| 5.0 mL | 3% | Dressings, cooking |
| 6.7 mL | 4% | Table vinegar |
| 8.3 mL | 5% | Pickling (5%+) |
| 10.0 mL | 6% | Pickling (5%+) |
| 11.7 mL | 7% | Pickling (5%+) |
| 13.3 mL | 8% | Dilute before use |
Know your strength
Is your homemade vinegar strong enough?
Homemade vinegar can be anywhere from 3% to over 7% acidity, and you cannot taste the difference reliably. Test it, then use the result to decide whether it goes into a pickle, a dressing or the next batch.
Use these reference values to interpret your results
- 5%
- 1% ABV ≈ 1%
Rule of thumb
Each 1% alcohol makes up to about 1% acidity; home batches land a little lower.
- 8.3 mL
Test reading
0.2 N sodium hydroxide for a 2 mL sample of 5% vinegar.
Titration formula
Acidity % = mL NaOH × N × 6.005 ÷ sample mLN is the normality of the sodium hydroxide (0.2 in most wine acid kits). 6.005 converts to grams of acetic acid per 100 mL. To dilute: water = volume × (current % ÷ target % − 1).
How to titrate homemade vinegar
You need a wine acid test kit (0.2 N sodium hydroxide, phenolphthalein indicator and a syringe or burette), distilled water and a small glass.
Measure exactly 2 mL of vinegar into the glass, add about 20 mL of distilled water and 3 drops of indicator. Add sodium hydroxide 0.5 mL at a time, swirling, then drop by drop as the pink flashes start to linger. Stop when a faint pink holds for 30 seconds and note how much you used.
Worked example
2 mL sample, 0.2 N sodium hydroxide, 9.0 mL usedAcidity = 9.0 × 0.2 × 6.005 ÷ 2 = 5.4%Strong enough for recipes that call for 5% vinegarWhy pH strips are not enough
Acetic acid is a weak acid, so most of it does not show up as pH. A 3% and a 6% vinegar can read almost the same pH, around 2.5–3. pH tells you vinegar is acidic; titration tells you how much acid is in it, which is the number canning and pickling recipes are built on.
Predicting strength from the starting ABV
Acetic acid bacteria turn alcohol into acid, so the alcohol you start with caps the acidity you can reach.
4–5% ABVBeer or light cider. About 3–4.5% vinegar; mild, for dressings.
6–7% ABVTypical hard cider. About 4.5–6%; the target range for ACV.
8–9% ABVDiluted wine. About 6–8%; dilute the finished vinegar to taste.
Over 10% ABVSlows the bacteria. Dilute wine with water to about 8% first.
Diluting vinegar to a target strength
Strong homemade wine vinegar can reach 7–8%. To bring it to 5%, add water = volume × (current ÷ target − 1). One litre of 7% vinegar needs 400 mL of water. Use distilled or boiled and cooled water, then retest if the vinegar is going into a canning recipe.
If your vinegar tests weak
Below 4% usually means the base was low in alcohol, the batch was not finished, or alcohol evaporated in a warm spot. Taste for any alcohol: if it is still there, give it more weeks. If it is fully sour but weak, use it for dressings and cooking, and start the next batch from a stronger cider or wine. Never use weak vinegar to can or pickle for the shelf.
FAQ
Vinegar Acidity Calculator questions
How do I test the acidity of homemade vinegar?
Titrate it. Dilute 2 mL of vinegar in about 20 mL of distilled water, add a few drops of phenolphthalein, then add 0.2 N sodium hydroxide from a wine acid test kit until the colour stays pink for 30 seconds. Enter the mL used and the calculator gives the acidity as percent acetic acid.
What is the formula for vinegar acidity?
Acidity % = mL of sodium hydroxide × its normality × 6.005 ÷ mL of vinegar sample. The 6.005 comes from the molar mass of acetic acid (60.05 g/mol). With a 2 mL sample and 0.2 N solution, every 1 mL of sodium hydroxide is 0.6% acidity.
Can I use pH strips instead?
Not to get a percentage. pH shows that vinegar is acidic, but vinegars with the same pH can have very different acetic acid content because acetic acid is a weak acid. For pickling and canning you need the titratable acidity, which only titration measures.
How strong does vinegar need to be for pickling?
Tested canning and pickling recipes assume vinegar of at least 5% acidity. If your homemade vinegar is weaker, keep it for dressings and cooking, or use it alongside a commercial 5% vinegar in recipes that are not canned.
How strong will my vinegar be?
In theory each 1% ABV in the base liquid becomes about 1% acetic acid. In an open jar some alcohol evaporates, so a 6% ABV cider usually finishes at about 4.5–5.5%. Wine above about 10% ABV should be diluted first, because high alcohol slows acetic acid bacteria.
How do I dilute vinegar to 5%?
Water to add = vinegar volume × (current acidity ÷ target acidity − 1). One litre of 7% vinegar needs 400 mL of water to reach 5%. You can only lower acidity by diluting; weak vinegar cannot be made stronger with water.
Vinegar guides and tools
Calculators and guides for your next step.
- How to make apple cider vinegar Calculator · From apple juice to finished ACV in about two months.
- How to make wine vinegar Calculator · Leftover wine, a mother and a crock.
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- ABV calculator Calculator · Alcohol by volume of your cider or wine from gravity readings.
