SOP: Determination of Total Solids in Vinegar

GIFSQ — Global Institute for Food Safety & Quality

Principle

The total solids are found gravimetrically: a measured volume of vinegar is evaporated to dryness, the residual acid is removed by repeated evaporation with water, and the residue is dried for 2.5 hr at 100° C.

Apparatus required

• Tared silica dish, 5 cm in diameter
• Boiling water bath
• Oven at 100° C
• Desiccator

Reagents

a. Water.

Procedure

Pipette 25 ml of the sample into the tared silica dish

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Evaporate to dryness on a boiling water bath

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Remove the acid which tends to remain in the total solids by three evaporations with water

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Dry for 2.5 hr in an oven at 100° C

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Cool in a desiccator and weigh

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Carry out the determination in duplicate

Calculation

Total solids (%) = (Wt of residue ÷ Volume of sample taken) × 100

Where,

• Wt of residue = weight of the dried residue (g)
• Volume of sample taken = volume of vinegar taken for evaporation (ml)

Precautions

• Do not omit the three evaporations with water; retained acetic acid keeps the residue from reaching a true dry weight.
• Cool the dish in a desiccator before every weighing.

References

Ranganna, S., Handbook of Analysis and Quality Control for Fruit and Vegetable Products, 2nd edition.