1.139
11.39
1.139
11.39
The Titratable Acidity Calculator computes the total acid content of a food or beverage sample from an acid-base titration. Unlike pH, which measures the intensity of acidity (H+ concentration), titratable acidity (TA) measures the total quantity of acid present in the sample — both dissociated and undissociated forms. This distinction makes TA a superior measure of flavour impact and preservation potential, as the total acid pool determines how much pH buffering capacity and antimicrobial protection the food possesses.
The procedure for measuring titratable acidity involves adding a known volume of food sample (the aliquot) to a burette filled with standardised sodium hydroxide (NaOH) solution. The NaOH is added dropwise until the endpoint is reached, typically indicated by a permanent colour change with phenolphthalein indicator (from colourless to faint pink at pH 8.1–8.3) or by potentiometric detection at pH 8.1 using a pH meter. The volume of NaOH consumed is recorded and the TA is calculated.
The formula for titratable acidity is: TA (% w/v) = (V_NaOH × N_NaOH × MW_acid) / (V_aliquot × 10). Results are expressed relative to the primary acid present in the food: wine and grape juice TA is expressed as tartaric acid (MW = 150 g/mol), most other fruit products as citric acid (MW = 192 g/mol, using one exchangeable proton, or 64 g/mol per equivalent), yogurt and fermented dairy as lactic acid (MW = 90 g/mol), and vinegar as acetic acid (MW = 60 g/mol). The default value of 134 g/mol corresponds to malic acid expressed per mole (133.1 g/mol), commonly used for apple products.
Regulatory standards set minimum TA values for many products. EU wine regulations require a minimum TA of 3.5 g/L (as tartaric acid) for all wines. Italian law specifies lemon juice must have TA of at least 5 % (as citric acid). US Standards of Identity for orange juice require minimum titratable acidity. These standards ensure product authenticity and consistent flavour quality.
Winemakers use TA alongside pH to characterise must acidity and make blending, acidification, and deacidification decisions. A wine with pH 3.5 and TA 7 g/L is well-balanced for a full-bodied red; a white wine with pH 3.1 and TA 9 g/L would be perceived as aggressively tart. Food product developers use TA to benchmark competitor products and ensure consistent formulations batch-to-batch.
TA (% w/v) = (V_NaOH in mL × N_NaOH × MW_acid in g/mol) / (V_aliquot in mL × 10). The factor of 10 converts the result from g/100 mL to per cent (w/v). Acid content in g/L is TA % multiplied by 10.
A result of 0.65 % w/v titratable acidity as tartaric acid in wine means 6.5 g of tartaric acid per litre. This is within the typical range for a balanced dry red wine (5.5–8.0 g/L). A result above 9 g/L would indicate a tart, potentially acidic wine requiring deacidification before bottling.
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0.72 % citric acid (7.2 g/L) in orange juice — within the expected range of 0.6–1.2 % for fresh orange juice.
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Results
Unusually high at 12.75 g/L — this wine would require deacidification. Typical balanced wine sits at 5.5–8 g/L TA as tartaric acid.
pH measures the intensity of acidity (the concentration of free H+ ions). Titratable acidity measures the total quantity of acid present — both dissociated and undissociated. TA correlates better with perceived sourness because it reflects the total acid reservoir that the palate senses as a drink is consumed and buffered by saliva.
Wine TA is conventionally expressed as tartaric acid (MW = 150 g/mol). Use MW = 150 for European and Australian wine standards. Some US winery labs express TA as sulphuric acid (MW = 49 g/mol) — check which standard applies to your context before reporting results.
Phenolphthalein changes from colourless to pink at pH 8.1–8.3, which corresponds to the theoretical endpoint for complete neutralisation of the common food acids. It provides a sharp, visible colour change in a nearly colourless food sample. For coloured samples (red wine, juice), a potentiometric endpoint at pH 8.2 is preferred.
Plain yogurt typically has TA of 0.6–1.0 % (as lactic acid). Mildly sour yogurt sits at 0.6–0.7 %; strongly sour yogurt reaches 0.9–1.0 %. Most manufacturers target 0.7–0.85 % for commercial plain yogurt.
Prepare NaOH at approximately 0.1 mol/L and standardise against primary standard potassium hydrogen phthalate (KHP, MW = 204.22 g/mol). Dissolve a weighed amount of KHP in water and titrate with NaOH to the phenolphthalein endpoint. Exact normality = g KHP / (V_NaOH x 0.20422).
Italian PDO lemon juice requires TA of at least 5 % (w/v) as citric acid. Typical fresh lemon juice contains 5–8 % citric acid. Commercial lemon juice concentrates may reach 15–20 % TA before dilution.
No. Sugar is neutral (neither acid nor base) and does not consume NaOH during titration. Titratable acidity specifically measures only acid content, so sugar does not interfere with the result.
Apple cider vinegar typically has TA of 4–8 % as acetic acid. The US FDA requires a minimum of 4 % acetic acid (40 grain vinegar) for sale as table vinegar. High-quality apple cider vinegar may reach 6–7 % TA.
Yes, but you must first homogenise the sample and prepare an aqueous extract. Common practice is to blend 10 g of sample with 100 mL distilled water, filter, and use the filtrate as the test solution. Adjust the formula to account for the dilution factor.
Kombucha TA (expressed as acetic acid) is monitored during fermentation to control sourness. Commercial kombucha targets TA of 0.5–0.8 % acetic acid for a well-balanced flavour. Over-fermented kombucha can reach TA above 1.5 %, producing a very sharp, vinegar-like taste.
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