Citric Acid — Frequently Asked Questions

Fine granular anhydrous citric acid, often around 30 to 100 mesh, is the usual choice. Its particle size is close to that of sugar and other powders, so it mixes evenly and resists segregation during filling. Very fine powder dissolves fastest but is dustier and more prone to caking, while coarse 8 to 40 mesh granules can separate from finer powders. Keep moisture low and use barrier packaging, because citric acid and bicarbonate in the same blend react if they get damp.

Typically around 0.1 % to 0.3 % of the finished drink, but the level is set by the target pH, the sweetness and the flavour profile rather than a fixed figure. Titratable acidity is normally specified as anhydrous citric acid, so if you buy monohydrate, multiply the anhydrous figure by about 1.094. Sodium citrate is often added to buffer the acid and round off sharpness.

High-methoxyl pectin needs both high soluble solids and low pH to set, typically around pH 3.0 to 3.3 in the finished jam. Citric acid is the usual acid for getting there. Too little acid gives a weak or runny set; too much can cause pre-gelling during filling and syneresis in the jar. Add the acid late in the boil, often as a solution, to avoid breaking down the pectin.

Citric acid is not a strong antioxidant itself, but it chelates the iron and copper ions that catalyse oxidation, so it strengthens antioxidants such as ascorbic acid and tocopherols. It is used this way in oils and fats, in cut fruit and vegetables to slow browning, and in drinks to protect colour and flavour. In the EU and UK it is authorised as an acid, acidity regulator and antioxidant rather than a preservative.

Anhydrous, with a low moisture specification. The water of crystallisation in monohydrate can be released during compression or storage and starts the reaction with the carbonate or bicarbonate before the tablet reaches the glass. Blend and press in low-humidity conditions and pack in moisture-tight tubes or foils.

Ask for the specification for the form and mesh range ordered, the safety data sheet and a certificate of analysis for each batch, plus allergen and GMO statements that include the fermentation substrate if your approval requires it. State whether you need conformity to E330 only or also to FCC, JECFA or a pharmacopoeia, so documents can be checked before the order is confirmed.